Kohler ECV940, ECV980, Command PRO ECV940, Command PRO ECV980 Service Manual

Page 1
ECV940 & ECV980
Service Manual
IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating
instruction of equipment that this engine powers.
Ensure engine is stopped and level before performing any maintenance or service.
2 Safety 3 Maintenance
5 Specifi cations 13 Tools and Aids 16 Troubleshooting 20 Air Cleaner/Intake 21 Electronic Fuel Injection (EFI) System 45 Governor System 55 Lubrication System 57 Electrical System 62 Starter System 66 Disassembly/Inspection and Service 83 Reassembly
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KohlerEngines.com
Page 2
Safety
SAFETY PRECAUTIONS
WARNING: A hazard that could result in death, serious injury, or substantial property damage.
CAUTION: A hazard that could result in minor personal injury or property damage.
NOTE: is used to notify people of important installation, operation, or maintenance information.
WARNING
Explosive Fuel can cause res and severe burns.
Do not fi ll fuel tank while engine is hot or running.
Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.
WARNING
Rotating Parts can cause severe injury.
Stay away while engine is in operation.
Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate engine with covers, shrouds, or guards removed.
WARNING
Carbon Monoxide can cause severe nausea, fainting or death.
Avoid inhaling exhaust fumes.
Engine exhaust gases contain poisonous carbon monoxide. Carbon monoxide is odorless, colorless, and can cause death if inhaled.
Accidental Starts can cause severe injury or death.
Disconnect and ground spark plug lead(s) before servicing.
Before working on engine or equipment, disable engine as follows: 1) Disconnect spark plug lead(s). 2) Disconnect negative (–) battery cable from battery.
Hot Parts can cause severe burns.
Do not touch engine while operating or just after stopping.
Never operate engine with heat shields or guards removed.
Cleaning Solvents can cause severe injury or death.
Use only in well ventilated areas away from ignition sources.
Carburetor cleaners and solvents are extremely fl ammable. Follow cleaner manufacturer’s warnings and instructions on its proper and safe use. Never use gasoline as a cleaning agent.
Electrical Shock can cause injury.
Do not touch wires while engine is running.
WARNING
WARNING
WARNING
CAUTION
Damaging Crankshaft and Flywheel can cause personal injury.
Using improper procedures can lead to broken fragments. Broken fragments could be thrown from engine. Always observe and use precautions and procedures when installing fl ywheel.
Failure to utilize or reassemble debris screen as designed could result in debris screen failure and serious personal injury.
High Pressure Fluids can puncture skin and cause severe injury or death.
Do not work on fuel system without proper training or safety equipment.
Fluid puncture injuries are highly toxic and hazardous. If an injury occurs, seek immediate medical attention.
Explosive Fuel can cause fi res and severe burns.
Fuel system ALWAYS remains under HIGH PRESSURE.
Wrap a shop towel completely around fuel pump module connector. Press release button(s) and slowly pull connector away from fuel pump module allowing shop towel to absorb any residual fuel in high pressure fuel line. Any spilled fuel must be completely wiped up immediately.
CAUTION
CAUTION
WARNING
WARNING
2 62 690 05 Rev. --KohlerEngines.com
Page 3
Maintenance
MAINTENANCE INSTRUCTIONS
WARNING
Accidental Starts can cause severe injury or death.
Disconnect and ground spark plug lead(s) before servicing.
Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair establishment or individual; however, warranty repairs must be performed by a Kohler authorized dealer.
MAINTENANCE SCHEDULE
Every 100 Hours or Annually¹
Change oil. Oil lter is recommended. Lubrication System
Remove cooling shrouds and clean cooling areas. Air Cleaner/Intake
Every 150 Hours¹
Check air cleaner element. Air Cleaner/Intake
Replace unique Electronic Fuel Injection (EFI) fuel lter.
Check oil cooler ns, clean as necessary. Lubrication System
Every 200 Hours
Change oil fi lter. Lubrication System
Before working on engine or equipment, disable engine as follows: 1) Disconnect spark plug lead(s). 2) Disconnect negative (–) battery cable from battery.
Every 300 Hours
Replace air cleaner element and check inner element. Air Cleaner/Intake
Every 600 Hours
Replace air cleaner inner element. Air Cleaner/Intake
Replace spark plugs and set gap. Electrical System
1
Perform these procedures more frequently under severe, dusty, dirty conditions.
REPAIRS/SERVICE PARTS
Kohler genuine service parts can be purchased from Kohler authorized dealers. To fi nd a local Kohler authorized dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada).
362 690 05 Rev. -- KohlerEngines.com
Page 4
Maintenance
°F
-20
020324060
50 80 100
°C
-30 -20
-10 0
10 20 30
40
75
10W-30
5W-30
SAE 30
20W-50
OIL RECOMMENDATIONS
We recommend use of Kohler oils for best performance. Other high-quality detergent oils (including synthetic) of API (American Petroleum Institute) service class SJ or higher are acceptable. Select viscosity based on air temperature at time of operation as shown in table below.
FUEL RECOMMENDATIONS
WARNING
Explosive Fuel can cause fi res and severe burns.
Do not fi ll fuel tank while engine is hot or running.
STORAGE
If engine will be out of service for 2 months or more follow procedure below.
1. Add Kohler PRO Series fuel treatment or equivalent to fuel tank. Run engine 2-3 minutes to get stabilized fuel into fuel system (failures due to untreated fuel are not warrantable).
2. Change oil while engine is still warm from operation. Remove spark plug(s) and pour about 1 oz. of engine oil into cylinder(s). Replace spark plug(s) and crank engine slowly to distribute oil.
3. Disconnect negative (-) battery cable.
4. Store engine in a clean, dry place.
Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.
NOTE: E15, E20 and E85 are NOT approved and
should NOT be used; effects of old, stale or contaminated fuel are not warrantable.
Fuel must meet these requirements:
Clean, fresh, unleaded gasoline.
Octane rating of 87 (R+M)/2 or higher.
Research Octane Number (RON) 90 octane minimum.
Gasoline up to 10% ethyl alcohol, 90% unleaded is
acceptable.
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blend (max 15% MTBE by volume) are approved.
Do not add oil to gasoline.
Do not over ll fuel tank.
Do not use gasoline older than 30 days.
4
62 690 05 Rev. --KohlerEngines.com
Page 5
Engine Dimensions
484.61 [19.08]
Specifi cations
Dimensions in millimeters.
Inch equivalents shown in [ ].
152.50 [6.00]
50.00 [1.97]
22.50 [0.89]
FLYWHEEL SIDE
45˚
124.23 [4.89]
45˚ 35˚
428.07 [16.85]
89.75 [3.53]
OIL
FILTER
MOUNTING
HOLE “A”
35˚
30.00 [1.18]
OIL FILL & DIPSTICK
55˚
M8x1.25 4 STUD
45˚
325.25 [12.81]
20.01 [0.79]
62.70 [2.47]
2x Ø 35.00 [1.38]
45.00 [1.77]
406.25 [15.99]
MOUNTING
HOLE “A”
89.80 [3.54]
ENGINE MOUNTING SURFACE
680.87 [26.81]
403.69 [15.89]
168.71 [6.64] SPARK PLUG
STARTER SIDE
60.00 [2.36]
84.06 [3.31]
275.20 [10.83]
120.45
89.80
[4.74]
[3.54]
MOUNTING HOLE “A”
89.80
45˚
[3.54]
45˚
ENGINE MOUNTING SURFACE ( PTO END)
60.00 [2.36]
93.59 [3.68]
Ø 254.00 [10.00]
M8x1.25-6H
25.0 [0.98] DEEP
55˚
7 HOLES
EXHAUST PORT #1
18.00 [0.71]
OIL DRAIN PLUG 1/2 NPT INCH
MOUNTING
HOLE “A”
49.80 [1.96]
ENGINE MOUNTING SURFACE
OIL PRESSURE SWITCH
70.59 [2.78]
EXHAUST PORT #2
VALVE COVER SIDE
KohlerEngines.com
562 690 05 Rev. --
Page 6
Specifi cations
ENGINE IDENTIFICATION NUMBERS
Kohler engine identifi cation numbers (model, specifi cation and serial) should be referenced for effi cient repair, ordering correct parts, and engine replacement.
Model . . . . . . . . . . . . . . . . . . . . . ECV940
EFI Command Engine
Vertical Shaft
Numerical Designation
Specifi cation . . . . . . . . . . . . . . . ECV940-0001
Serial . . . . . . . . . . . . . . . . . . . . . 4323500328
Year Manufactured Code Factory Code Code Year 43 2013 44 2014 45 2015
GENERAL SPECIFICATIONS
3,6
ECV940 ECV980
Bore 90 mm (3.54 in.) Stroke 78.5 mm (3.1 in.) Displacement 999 cc (61 cu. in.) Oil Capacity (refi ll) 2.9 L (3.1 U.S. qt.) Maximum Angle of Operation (@ full oil level)
TORQUE SPECIFICATIONS
3,5
4
ECV940 ECV980
25°
Blower Housing and Sheet Metal
M6 Screw New, Untapped Hole (casting) Used, Tapped Hole (casting) New, Extruded Hole (sheet metal) Used, Extruded Hole (sheet metal) Mounting Clip (valley baffl e)
10.7 N·m (95 in. lb.)
7.3 N·m (65 in. lb.)
2.5 N·m (22 in. lb.)
2.0 N·m (18 in. lb.)
2.5 N·m (22 in. lb.)
Intake Manifold and Air Cleaner
Intake Manifold Mounting Fastener (torque in 2 increments) fi rst to 16.9 N·m (150 in. lb.)
nally to 22.6 N·m (200 in. lb.) Air Cleaner Elbow to Throttle Body Mounting Nut 7.9 N·m (70 in. lb.) Air Cleaner Bracket Mounting Screw (into intake manifold) 11.3 N·m (100 in. lb.) GCU Bracket to Intake Manifold & Air Cleaner Bracket 11.3 N·m (100 in. lb.) Ground Lead to Air Cleaner Bracket 5.6 N·m (50 in. lb.) Fuel Injector Cap Fastener 7.3 N·m (65 in. lb.) Manifold Absolute Pressure (MAP) Sensor Fastener 7.3 N·m (65 in. lb.)
Connecting Rod
Cap Fastener (torque in increments) 11.6 N·m (103 in. lb.)
3
Values are in Metric units. Values in parentheses are English equivalents.
4
Exceeding maximum angle of operation may cause engine damage from insuffi cient lubrication.
5
Lubricate threads with engine oil prior to assembly.
6
Any and all horsepower (hp) references by Kohler are Certifi ed Power Ratings and per SAE J1940 & J1995 hp
standards. Details on Certifi ed Power Ratings can be found at KohlerEngines.com.
6
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Page 7
Specifi cations
TORQUE SPECIFICATIONS
3,5
ECV940 ECV980
Crankcase
Breather Cover Fastener 12.4 N·m (110 in. lb.) Oil Drain Plug 21.4 N·m (16 ft. lb.) Oil Temperature Sensor 7.3 N·m (65 in. lb.) Dipstick Tube Screw 7.7 N·m (68 in. lb.)
Cylinder Head
Fastener (torque in 2 increments) Head Bolt fi rst to 23.7 N·m (210 in. lb.)
nally to 46.9 N·m (415 in. lb.) Pipe Plug 3/4 in. 28.5 N·m (252 in. lb.) Rocker Arm Stud (AVT) 11.3 N·m (100 in. lb.) Rocker Arm Screw (Non-AVT) 15.5 N·m (137 in. lb.) Setscrew, AVT pivot locking 7.7 N·m (69 in. lb.)
Debris Screen
Hex Stud 21.5 N·m (190 in. lb.) Mounting Screw - Hex Flange Screw 20.3 N·m (180 in. lb.) Mounting Screw - Button Head Cap Screw 9.9 N·m (88 in. lb.)
Flywheel
Fan Fastener 10.4 N·m (92 in. lb.) Retaining Screw 69.8 N·m (51 ft. lb.)
Fuel Pump
Module Baffl e to Crankcase Fastener 11.9 N·m (105 in. lb.) Module to Baffl e Fastener 9.2 N·m (81 in. lb.) Pulse Pump Screw (to blower housing) 2.8 N·m (25 in. lb.)
Governor (Electronic)
Governor Control Unit (GCU) to GCU Bracket 2.1 N·m (19 in. lb.) Digital Linear Actuator (DLA) Bracket to GCU Bracket 10.2 N·m (90 in. lb.) DLA to DLA Bracket Screw 7.3 N·m (65 in. lb.)
Governor (Mechanical)
Lever Nut 7.1 N·m (63 in. lb.) Yoke Mounting Screw 2.2 N·m (20 in. lb.)
Ignition
Spark Plug 27 N·m (20 ft. lb.) Coil Fastener 5.1 N·m (45 in. lb.) Crankshaft Position Sensor Screw 11.3 N·m (100 in. lb.) Crankshaft Position Sensor Bracket Screw 9.7 N·m (86 in. lb.) Electronic Control Unit (ECU) to Bracket Screw 6.2 N·m (55 in. lb.) Rectifi er-Regulator Fastener 2.5 N·m (22 in. lb.)
Lifter Feed Chamber Cover
Screw 6.6 N·m (58 in. lb.)
3
Values are in Metric units. Values in parentheses are English equivalents.
5
Lubricate threads with engine oil prior to assembly.
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762 690 05 Rev. --
Page 8
Specifi cations
TORQUE SPECIFICATIONS
3,5
ECV940 ECV980
Muffl er
Retaining Nut 24.4 N·m (216 in. lb.) Screw, intermittent bracket (into weld nut) 13.6 N·m (120 in. lb.) M6 Screw 9.9 N·m (88 in. lb.) M8 Screw 24.4 N·m (216 in. lb.)
Oil Cooler
Mounting Screw 2.3 N·m (21 in. lb.)
Oil Filter Adapter/Housing
Mounting Screw 23.7 N·m (210 in. lb.) Oil Filter Nipple 17.8 N·m (158 in. lb.)
Oil Pan
Fastener 25.6 N·m (227 in. lb.) Oil Temperature Sensor 13.6 N·m (120 in. lb.) Oil Temperature Sensor Reducer Bushing 17.6 N·m (156 in. lb.) Oil Temperature Sensor Nut 2.3 N·m (20 in. lb.)
Oil Pickup Screen
Mounting Screw 11.3 N·m (100 in. lb.) into a new hole
7.7 N·m (68 in. lb.) into a used hole
Oil Pump
Mounting Screw 9.9 N·m (88 in. lb.)
Oil Sentry
TM
Pressure Switch 10.7 N·m (95 in. lb.)
Solenoid (starter)
Mounting Hardware 4.0-6.0 N·m (35-53 in. lb.) Nut, Positive (+) Brush Lead 8.0-11.0 N·m (71-97 in. lb.)
Starter Assembly
Thru Bolt 5.6-9.0 N·m (49-79 in. lb.) Mounting Screw 16 N·m (142 in. lb.) Brush Holder Mounting Screw 2.5-3.3 N·m (22-29 in. lb.)
Stator
Mounting Screw 9.3 N·m (82 in. lb.)
Throttle Control Bracket
Fastener 9.9 N·m (88 in. lb.)
Valve Cover
Fastener 13.6 N·m (120 in. lb.)
3
Values are in Metric units. Values in parentheses are English equivalents.
5
Lubricate threads with engine oil prior to assembly.
8
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Page 9
Specifi cations
CLEARANCE SPECIFICATIONS
3
ECV940 ECV980
Camshaft
End Play 0.3/1.3 mm (0.011/0.051 in.) Running Clearance 0.025/0.063 mm (0.0010/0.0025 in.) Bore I.D.
New Max. Wear Limit
20.000/20.025 mm (0.7874/0.7884 in.)
20.038 mm (0.7889 in.)
Bearing Surface O.D. New Max. Wear Limit
19.962/19.975 mm (0.7859/0.7864 in.)
19.959 mm (0.7858 in.)
Cam Lobe Profi le (minimum dimension, measured from base circle to top of lobe) Exhaust 35 mm (1.3779 in.)
Intake 34.1 mm (1.3425 in.) 35 mm (1.3779 in.)
Connecting Rod
Crankpin End I.D. @ 70°F New Max. Wear Limit
44.030/44.037 mm (1.7334/1.7337 in.)
0.070 mm (0.0028 in.)
Connecting Rod-to-Crankpin Running Clearance New Max. Wear Limit
0.030/0.055 mm (0.0012/0.0022 in.)
0.070 mm (0.0028 in.) Connecting Rod-to-Crankpin Side Clearance 0.30/0.59 mm (0.0118/0.0232 in.) Connecting Rod-to-Piston Pin Running Clearance 0.015/0.028 mm (0.0006/0.0011 in.) Piston Pin End I.D. @ 70°F
New Max. Wear Limit
19.015/19.023 mm (0.7486/0.7489 in.)
19.036 mm (0.7494 in.)
Crankcase
Governor Cross Shaft Bore I.D. (Mechanical Governor) New Max. Wear Limit
8.025/8.050 mm (0.3159/0.3169 in.)
8.088 mm (0.3184 in.)
Crankshaft
End Play (free) 0.30/1.50 mm (0.011/0.059 in.) Bore (in crankcase)
New 45.043/45.068 mm (1.7733/1.7743 in.) Crankshaft Bore (in crankcase)-to-Crankshaft Running Clearance
New 0.043/0.090 mm (0.0017/0.0035 in.) Bore (in oil pan)
New, Without Bearing 50.025/50.00 mm (1.9694/1.9685 in.) Crankshaft to Sleeve Bearing (in oil pan) Running Clearance
New 0.040/0.167 mm (0.0015/0.0065 in.) Oil Pan End Main Bearing Journal
O.D. - New O.D. - Max. Wear Limit Max. Taper Max. Out-of-Round
44.978/45.00 mm (1.770/1.771 in.)
44.90 mm (1.767 in.)
0.022 mm (0.0009 in.)
0.025 mm (0.0010 in.) Connecting Rod Journal
O.D. - New O.D. - Max. Wear Limit Max. Taper Max. Out-of-Round Width
43.982/44.000 mm (1.731/1.732 in.)
43.97 mm (1.731 in.)
0.018 mm (0.0007 in.)
0.025 mm (0.0010 in.)
53.00/53.09 mm (2.0866/2.0901 in.)
3
Values are in Metric units. Values in parentheses are English equivalents.
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962 690 05 Rev. --
Page 10
Specifi cations
CLEARANCE SPECIFICATIONS
3
ECV940 ECV980
Crankshaft Continued
T.I.R. PTO End, Crank in Engine Entire Crank, in V-Blocks
0.279 mm (0.0110 in.)
0.10 mm (0.0039 in.)
Flywheel End Main Bearing Journal O.D. - New O.D. - Max. Wear Limit Max. Taper Max. Out-of-Round
44.978/45.00 mm (1.770/1.771 in.)
44.90 mm (1.767 in.)
0.022 mm (0.0009 in.)
0.025 mm (0.0010 in.)
Crankshaft Bearing (PTO)
New (installed) Max. Wear Limit
45.040/45.145 mm (1.773.1.777 in.)
45.158 mm
Cylinder Bore
I.D. New Max. Wear Limit Max. Taper Max. Out-of-Round
90.000/90.025 mm (3.543/3.544 in.)
90.075 mm (3.546 in.)
0.013 mm (0.00051 in.)
0.013 mm (0.00051 in.)
Cylinder Head
Max. Out-of-Flatness 0.076 mm (0.003 in.)
Governor (Mechanical)
Governor Cross Shaft-to-Crankcase Running Clearance 0.025/0.087 mm (0.0009/0.0034 in.) Cross Shaft O.D.
New
7.963/8.000 mm (0.3135/.3149 in.)
7.936 mm (0.3124 in.)
Max. Wear Limit Governor Gear Shaft-to-Governor Gear Running Clearance 0.070/0.160 mm (0.0027/0.0063 in.) Gear Shaft O.D.
New Max. Wear Limit
5.990/6.000 mm (0.2358/0.2362 in.)
5.977 mm (0.2353 in.)
Ignition
Spark Plug Gap 0.76 mm (0.030 in.) Module Air Gap 0.28/0.33 mm (0.011/0.013 in.)
Piston, Piston Rings, and Piston Pin
Piston-to-Piston Pin Running Clearance 0.006/0.018 mm (0.0002/0.0007 in.) Pin Bore I.D.
New Max. Wear Limit
19.006/17.013 mm (0.7482/0.7485 in.)
19.025 mm (0.7490 in.)
Pin O.D. New Max. Wear Limit
18.995/19.000 mm (0.7478/0.7480 in.)
18.994 mm (0.7478 in.) Top Compression Ring-to-Groove Side Clearance 0.04/0.08 mm (0.0015/0.0031 in.) Middle Compression Ring-to-Groove Side Clearance 0.04/0.08 mm (0.0015/0.0031 in.) Oil Control Ring-to-Groove Side Clearance 0.03/0.19 mm (0.0011/0.0074 in.) Top and Center Compression Ring End Gap
New Bore Used Bore (max.)
3
Values are in Metric units. Values in parentheses are English equivalents.
10
0.30/0.55 mm (0.011/0.021 in.)
0.94 mm (0.037 in.)
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Page 11
Specifi cations
CLEARANCE SPECIFICATIONS
3
ECV940 ECV980
Piston, Piston Rings, and Piston Pin Continued
Thrust Face O.D. New Max. Wear Limit
7
89.953/89.967 mm (3.5414/3.5420 in.)
89.925 mm (3.540 in.)
Piston Thrust Face-to-Cylinder Bore7 Running Clearance New 0.033/0.071 mm (0.0013/0.0028 in.)
Valves and Valve Lifters
Hydraulic Valve Lifter to Crankcase Running Clearance 0.012/0.050 mm (0.0004/0.0019 in.) Intake Valve Stem-to-Valve Guide Running Clearance 0.038/0.076 mm (0.0015/0.0030 in.) Exhaust Valve Stem-to-Valve Guide Running Clearance 0.050/0.088 mm (0.0020/0.0035 in.) Intake Valve Guide I.D.
New Max. Wear Limit
7.038/7.058 mm (0.2771/0.2779 in.)
7.135 mm (0.2809 in.)
Exhaust Valve Guide I.D. New Max. Wear Limit
7.038/7.058 mm (0.2771/0.2779 in.)
7.159 mm (0.2819 in.)
Guide Reamer Size Standard
0.25 mm O.S.
7.048 mm (0.2775 in.)
7.298 mm (0.2873 in.)
Nominal Valve Face Angle 45°
3
Values are in Metric units. Values in parentheses are English equivalents.
7
Measure 11 mm (0.4331 in.) above bottom of piston skirt at right angles to piston pin.
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1162 690 05 Rev. --
Page 12
Specifi cations
GENERAL TORQUE VALUES
English Fastener Torque Recommendations for Standard Applications
Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel
Size Grade 2 Grade 5 Grade 8
Tightening Torque: N·m (in. lb.) ± 20%
8-32 2.3 (20) 2.8 (25) 2.3 (20) 10-24 3.6 (32) 4.5 (40) 3.6 (32) 10-32 3.6 (32) 4.5 (40)
1/4-20 7.9 (70) 13.0 (115) 18.7 (165) 7.9 (70)
1/4-28 9.6 (85) 15.8 (140) 22.6 (200) — 5/16-18 17.0 (150) 28.3 (250) 39.6 (350) 17.0 (150) 5/16-24 18.7 (165) 30.5 (270)
3/8-16 29.4 (260)
3/8-24 33.9 (300)
Tightening Torque: N·m (ft. lb.) ± 20%
5/16-24 40.7 (30)
3/8-16 47.5 (35) 67.8 (50)
3/8-24 54.2 (40) 81.4 (60) — 7/16-14 47.5 (35) 74.6 (55) 108.5 (80) — 7/16-20 61.0 (45) 101.7 (75) 142.5 (105)
1/2-13 67.8 (50) 108.5 (80) 155.9 (115)
1/2-20 94.9 (70) 142.4 (105) 223.7 (165) — 9/16-12 101.7 (75) 169.5 (125) 237.3 (175) — 9/16-18 135.6 (100) 223.7 (165) 311.9 (230)
5/8-11 149.5 (110) 244.1 (180) 352.6 (260)
5/8-18 189.8 (140) 311.9 (230) 447.5 (330)
3/4-10 199.3 (147) 332.2 (245) 474.6 (350)
3/4-16 271.2 (200) 440.7 (325) 637.3 (470)
Grade 2 or 5 Fasteners
Into Aluminum
Metric Fastener Torque Recommendations for Standard Applications
Size
4.8
5.8
Tightening Torque: N·m (in. lb.) ± 10%
M4 1.2 (11) 1.7 (15) 2.9 (26) 4.1 (36) 5.0 (44) 2.0 (18) M5 2.5 (22) 3.2 (28) 5.8 (51) 8.1 (72) 9.7 (86) 4.0 (35) M6 4.3 (38) 5.7 (50) 9.9 (88) 14.0 (124) 16.5 (146) 6.8 (60) M8 10.5 (93) 13.6 (120) 24.4 (216) 33.9 (300) 40.7 (360) 17.0 (150)
Tightening Torque: N·m (ft. lb.) ± 10%
M10 21.7 (16) 27.1 (20) 47.5 (35) 66.4 (49) 81.4 (60) 33.9 (25) M12 36.6 (27) 47.5 (35) 82.7 (61) 116.6 (86) 139.7 (103) 61.0 (45) M14 58.3 (43) 76.4 (56) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)
12
Property Class
8.8
10.9 12.9
Torque Conversions
N·m = in. lb. x 0.113 in. lb. = N·m x 8.85
N·m = ft. lb. x 1.356 ft. lb. = N·m x 0.737
Noncritical
Fasteners
Into Aluminum
62 690 05 Rev. --KohlerEngines.com
Page 13
Tools and Aids
Certain quality tools are designed to help you perform specifi c disassembly, repair, and reassembly procedures. By using these tools, you can properly service engines easier, faster, and safer! In addition, you’ll increase your service capabilities and customer satisfaction by decreasing engine downtime.
Here is a list of tools and their source.
SEPARATE TOOL SUPPLIERS
Kohler Tools Contact your local Kohler source of supply.
TOOLS
Description Source/Part No.
Alcohol Content Tester
For testing alcohol content (%) in reformulated/oxygenated fuels.
Camshaft Endplay Plate
For checking camshaft endplay.
Camshaft Seal Protector (Aegis)
For protecting seal during camshaft installation.
Cylinder Leakdown Tester
For checking combustion retention and if cylinder, piston, rings, or valves are worn. Individual component available: Adapter 12 mm x 14 mm (Required for leakdown test on XT-6 engines)
Dealer Tool Kit (Domestic)
Complete kit of Kohler required tools. Components of 25 761 39-S Ignition System Tester Cylinder Leakdown Tester Oil Pressure Test Kit Rectifi er-Regulator Tester (120 V AC/60Hz)
Dealer Tool Kit (International)
Complete kit of Kohler required tools. Components of 25 761 42-S Ignition System Tester Cylinder Leakdown Tester Oil Pressure Test Kit Rectifi er-Regulator Tester (240 V AC/50Hz)
Digital Vacuum/Pressure Tester
For checking crankcase vacuum. Individual component available: Rubber Adapter Plug
Electronic Fuel Injection (EFI) Diagnostic Software
For Laptop or Desktop PC.
EFI Service Kit
For troubleshooting and setting up an EFI engine. Components of 24 761 01-S Fuel Pressure Tester Noid Light 90° Adapter In-line "T" Fitting Code Plug, Red Wire Code Plug, Blue Wire Shrader Valve Adapter Hose
Flywheel Holding Tool (CS)
For holding fl ywheel of CS series engines.
Flywheel Puller
For properly removing fl ywheel from engine.
Flywheel Strap Wrench
For holding fl ywheel during removal.
SE Tools 415 Howard St. Lapeer, MI 48446 Phone 810-664-2981 Toll Free 800-664-2981 Fax 810-664-8181
Design Technology Inc. 768 Burr Oak Drive Westmont, IL 60559 Phone 630-920-1300 Fax 630-920-0011
Kohler 25 455 11-S
SE Tools KLR-82405
SE Tools KLR-82417
Kohler 25 761 05-S
Design Technology Inc.
DTI-731-03
Kohler 25 761 39-S
Kohler 25 455 01-S Kohler 25 761 05-S Kohler 25 761 06-S Kohler 25 761 20-S
Kohler 25 761 42-S
Kohler 25 455 01-S Kohler 25 761 05-S Kohler 25 761 06-S Kohler 25 761 41-S
Design Technology Inc.
DTI-721-01
Design Technology Inc.
DTI-721-10
Kohler 25 761 23-S
Kohler 24 761 01-S
Design Technology Inc.
DTI-019 DTI-021 DTI-023 DTI-035 DTI-027 DTI-029 DTI-037
SE Tools KLR-82407
SE Tools KLR-82408
SE Tools KLR-82409
1362 690 05 Rev. -- KohlerEngines.com
Page 14
Tools and Aids
TOOLS
Description Source/Part No.
Hydraulic Valve Lifter Tool
For removing and installing hydraulic lifters.
Ignition System Tester
For testing output on all systems, including CD.
Inductive Tachometer (Digital)
For checking operating speed (RPM) of an engine.
Offset Wrench (K and M Series)
For removing and reinstalling cylinder barrel retaining nuts.
Oil Pressure Test Kit
For testing/verifying oil pressure on pressure lubricated engines.
Radiator Tester
For pressure testing radiator and cap on Aegis liquid-cooled engines.
Rectifi er-Regulator Tester (120 volt current) Rectifi er-Regulator Tester (240 volt current)
For testing rectifi er-regulators. Components of 25 761 20-S and 25 761 41-S CS-PRO Regulator Test Harness Special Regulator Test Harness with Diode
Spark Advance Module (SAM) Tester
For testing SAM (ASAM and DSAM) on engines with SMART-SPARK
.
Starter Servicing Kit (All Starters)
For removing and reinstalling drive retaining rings and brushes. Individual component available: Starter Brush Holding Tool (Solenoid Shift)
Triad/OHC Timing Tool Set
For holding cam gears and crankshaft in timed position while installing timing belt.
Valve Guide Reamer (K and M Series)
For properly sizing valve guides after installation.
Valve Guide Reamer O.S. (Command Series)
For reaming worn valve guides to accept replacement oversize valves. Can be used in low-speed drill press or with handle below for hand reaming.
Reamer Handle
For hand reaming using Kohler 25 455 12-S reamer.
Valve Guide Service Kit (Courage, Aegis, Command, OHC)
For servicing worn valve guides.
Kohler 25 761 38-S
Kohler 25 455 01-S
Design Technology Inc.
DTI-110
Kohler 52 455 04-S
Kohler 25 761 06-S
Kohler 25 455 10-S
Kohler 25 761 20-S Kohler 25 761 41-S
Design Technology Inc.
DTI-031 DTI-033
Kohler 25 761 40-S
SE Tools KLR-82411
SE Tools KLR-82416
Kohler 28 761 01-S
Design Technology Inc.
DTI-K828
Kohler 25 455 12-S
Design Technology Inc.
DTI-K830
SE Tools KLR-82415
AIDS Description Source/Part No.
Camshaft Lubricant (Valspar ZZ613) Kohler 25 357 14-S Dielectric Grease (GE/Novaguard G661) Kohler 25 357 11-S Dielectric Grease Loctite® 51360 Kohler Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S Kohler Electric Starter Drive Lubricant (Solenoid Shift) Kohler 52 357 02-S RTV Silicone Sealant
Loctite® 5900® Heavy Body in 4 oz. aerosol dispenser. Only oxime-based, oil resistant RTV sealants, such as those listed, are approved
for use. Loctite® Nos. 5900® or 5910® are recommended for best sealing characteristics.
Spline Drive Lubricant Kohler 25 357 12-S
14 62 690 05 Rev. --KohlerEngines.com
Kohler 25 597 07-S
Loctite® 5910
®
Loctite® Ultra Black 598™
Loctite® Ultra Blue 587™
Loctite® Ultra Copper 5920™
Page 15
Tools and Aids
FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL
A ywheel holding tool can be made out of an old junk ywheel ring gear and used in place of a strap wrench.
1. Using an abrasive cut-off wheel, cut out a six tooth segment of ring gear as shown.
2. Grind off any burrs or sharp edges.
3. Invert segment and place it between ignition bosses on crankcase so tool teeth engage fl ywheel ring gear teeth. Bosses will lock tool and fl ywheel in position for loosening, tightening, or removing with a puller.
A spanner wrench to lift rocker arms or turn crankshaft may be made out of an old junk connecting rod.
1. Find a used connecting rod from a 10 HP or larger engine. Remove and discard rod cap.
2. Remove studs of a Posi-Lock rod or grind off aligning steps of a Command rod, so joint surface is at.
3. Find a 1 in. long capscrew with correct thread size to match threads in connecting rod.
4. Use a fl at washer with correct I.D. to slip on capscrew and approximately 1 in. O.D. Assemble capscrew and washer to joint surface of rod.
1562 690 05 Rev. -- KohlerEngines.com
Page 16
Troubleshooting
TROUBLESHOOTING GUIDE
When troubles occur, be sure to check simple causes which, at fi rst, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank.
Some general common causes of engine troubles are listed below and vary by engine specifi cation. Use these to locate causing factors.
Engine Cranks But Will Not Start
Battery connected backwards.
Blown fuse.
Carburetor solenoid malfunction.
Choke not closing.
Clogged fuel line or fuel lter.
Diode in wiring harness failed in open circuit mode.
DSAI or DSAM malfunction.
Empty fuel tank.
Faulty electronic control unit.
Faulty ignition coil(s).
Faulty spark plug(s).
Fuel pump malfunction-vacuum hose clogged or
leaking.
Fuel shut-off valve closed.
Ignition module(s) faulty or improperly gapped.
Insuf cient voltage to electronic control unit.
Interlock switch is engaged or faulty.
Key switch or kill switch in OFF position.
Low oil level.
Quality of fuel (dirt, water, stale, mixture).
SMART-SPARKTM malfunction.
Spark plug lead(s) disconnected.
Engine Starts But Does Not Keep Running
Faulty carburetor.
Faulty cylinder head gasket.
Faulty or misadjusted choke or throttle controls.
Fuel pump malfunction-vacuum hose clogged or
leaking.
Intake system leak.
Loose wires or connections that intermittently ground
ignition kill circuit.
Quality of fuel (dirt, water, stale, mixture).
Restricted fuel tank cap vent.
Engine Starts Hard
Clogged fuel line or fuel lter.
Engine overheated.
Faulty ACR mechanism.
Faulty or misadjusted choke or throttle controls.
Faulty spark plug(s).
Flywheel key sheared.
Fuel pump malfunction-vacuum hose clogged or
leaking.
Interlock switch is engaged or faulty.
Loose wires or connections that intermittently ground
ignition kill circuit.
Low compression.
Quality of fuel (dirt, water, stale, mixture).
Weak spark.
Engine Will Not Crank
Battery is discharged.
Faulty electric starter or solenoid.
Faulty key switch or ignition switch.
Interlock switch is engaged or faulty.
Loose wires or connections that intermittently ground
ignition kill circuit.
Pawls not engaging in drive cup.
Seized internal engine components.
Engine Runs But Misses
Carburetor adjusted incorrectly.
Engine overheated.
Faulty spark plug(s).
Ignition module(s) faulty or improperly gapped.
Incorrect crankshaft position sensor air gap.
Interlock switch is engaged or faulty.
Loose wires or connections that intermittently ground
ignition kill circuit.
Quality of fuel (dirt, water, stale, mixture).
Spark plug lead(s) disconnected.
Spark plug lead boot loose on plug.
Spark plug lead loose.
Engine Will Not Idle
Engine overheated.
Faulty spark plug(s).
Idle fuel adjusting needle(s) improperly set.
Idle speed adjusting screw improperly set.
Inadequate fuel supply.
Low compression.
Quality of fuel (dirt, water, stale, mixture).
Restricted fuel tank cap vent.
Engine Overheats
Cooling fan broken.
Excessive engine load.
Fan belt failed/off.
Faulty carburetor.
High crankcase oil level.
Lean fuel mixture.
Low cooling system uid level.
Low crankcase oil level.
Radiator, and/or cooling system components clogged,
restricted, or leaking.
Water pump belt failed/broken.
Water pump malfunction.
Engine Knocks
Excessive engine load.
Hydraulic lifter malfunction.
Incorrect oil viscosity/type.
Internal wear or damage.
Low crankcase oil level.
Quality of fuel (dirt, water, stale, mixture).
16 62 690 05 Rev. --KohlerEngines.com
Page 17
Troubleshooting
Engine Loses Power
Dirty air cleaner element.
Engine overheated.
Excessive engine load.
Restricted exhaust.
Faulty spark plug(s).
High crankcase oil level.
Incorrect governor setting.
Low battery.
Low compression.
Low crankcase oil level.
Quality of fuel (dirt, water, stale, mixture).
Engine Uses Excessive Amount of Oil
Loose or improperly torqued fasteners.
Blown head gasket/overheated.
Breather reed broken.
Clogged, broken, or inoperative crankcase breather.
Crankcase over lled.
Incorrect oil viscosity/type.
Worn cylinder bore.
Worn or broken piston rings.
Worn valve stems/valve guides.
Oil Leaks from Oil Seals, Gaskets
Breather reed broken.
Clogged, broken, or inoperative crankcase breather.
Loose or improperly torqued fasteners.
Piston blow by, or leaky valves.
Restricted exhaust.
EXTERNAL ENGINE INSPECTION
NOTE: It is good practice to drain oil at a location away
from workbench. Be sure to allow ample time for complete drainage.
Before cleaning or disassembling engine, make a thorough inspection of its external appearance and condition. This inspection can give clues to what might be found inside engines (and cause) when it is disassembled.
Check for buildup of dirt and debris on crankcase,
cooling fi ns, grass screen, and other external surfaces. Dirt or debris on these areas can cause overheating.
Check for obvious fuel and oil leaks, and damaged
components. Excessive oil leakage can indicate a clogged or inoperative breather, worn or damaged seals or gaskets, or loose fasteners.
Check air cleaner cover and base for damage or
indications of improper fi t and seal.
Check air cleaner element. Look for holes, tears,
cracked or damaged sealing surfaces, or other damage that could allow unfi ltered air into engine. A dirty or clogged element could indicate insuffi cient or improper maintenance.
Check carburetor throat for dirt. Dirt in throat is further
indication that air cleaner was not functioning properly.
Check if oil level is within operating range on dipstick.
If it is above, sniff for gasoline odor.
Check condition of oil. Drain oil into a container; it
should fl ow freely. Check for metal chips and other foreign particles.
Sludge is a natural by-product of combustion; a small
accumulation is normal. Excessive sludge formation could indicate over rich fuel settings, weak ignition, overextended oil change interval or wrong weight or type of oil was used.
CLEANING ENGINE
WARNING
Cleaning Solvents can cause severe injury or death.
Use only in well ventilated areas away from ignition sources.
Carburetor cleaners and solvents are extremely ammable. Follow cleaner manufacturer’s warnings and instructions on its proper and safe use. Never use gasoline as a cleaning agent.
After inspecting external condition of engine, clean engine thoroughly before disassembly. Clean individual components as engine is disassembled. Only clean parts can be accurately inspected and gauged for wear or damage. There are many commercially available cleaners that will quickly remove grease, oil, and grime from engine parts. When such a cleaner is used, follow manufacturer’s instructions and safety precautions carefully.
Make sure all traces of cleaner are removed before engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down lubricating properties of engine oil.
1762 690 05 Rev. -- KohlerEngines.com
Page 18
Troubleshooting
CRANKCASE VACUUM TEST
WARNING
Carbon Monoxide can cause severe nausea, fainting or death.
Avoid inhaling exhaust fumes.
Engine exhaust gases contain poisonous carbon monoxide. Carbon monoxide is odorless, colorless, and can cause death if inhaled.
A partial vacuum should be present in crankcase when engine is operating. Pressure in crankcase (normally caused by a clogged or improperly assembled breather) can cause oil to be forced out at oil seals, gaskets, or other available spots.
Crankcase vacuum is best measured with either a water manometer or a vacuum gauge. Complete instructions are provided in kits.
To test crankcase vacuum with manometer:
1. Insert rubber stopper into oil fi ll hole. Be sure pinch clamp is installed on hose and use tapered adapters to connect hose between stopper and one manometer tube. Leave other tube open to atmosphere. Check that water level in manometer is at 0 line. Make sure pinch clamp is closed.
2. Start engine and run no-load high speed.
3. Open clamp and note water level in tube.
Level in engine side should be a minimum of 10.2
cm (4 in.) above level in open side.
If level in engine side is less than specifi ed (low/no
vacuum), or level in engine side is lower than level in open side (pressure), check for conditions in table below.
4. Close pinch clamp before stopping engine.
Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate engine with covers, shrouds, or guards removed.
To test crankcase vacuum with vacuum/pressure gauge:
1. Remove dipstick or oil fi ll plug/cap.
2. Install adapter into oil fi ll/dipstick tube opening,
3. Run engine and observe gauge reading. Analog tester–needle movement to left of 0 is a
Digital tester–depress test button on top of tester. Crankcase vacuum should be a minimum of 10.2 cm
Rotating Parts can cause severe injury. Stay away while engine is in operation.
upside down over end of a small diameter dipstick tube, or directly into engine if a tube is not used. Insert barbed gauge fi tting into hole in stopper.
vacuum, and movement to right indicates a pressure.
(4 in.) of water. If reading is below specifi cation, or if pressure is present, check table below for possible causes and conclusions.
WARNING
Condition Conclusion
Crankcase breather clogged or inoperative. NOTE: If breather is integral part of valve cover and
cannot be serviced separately, replace valve cover and recheck pressure.
Disassemble breather, clean parts thoroughly, check sealing surfaces for fl atness, reassemble, and recheck pressure.
Seals and/or gaskets leaking. Loose or improperly torque fasteners.
Piston blow by or leaky valves (confi rm by inspecting components).
Restricted exhaust. Check exhaust screen/spark arrestor (if equipped). Clean
Replace all worn or damaged seals and gaskets. Make sure all fasteners are tightened securely. Use appropriate torque valves and sequences when necessary.
Recondition piston, rings, cylinder bore, valves and valves guides.
or replace as needed. Repair or replace any other damaged/restricted muffl er or exhaust system parts.
18 62 690 05 Rev. --KohlerEngines.com
Page 19
Troubleshooting
COMPRESSION TEST
For Command Twins: A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s)
before removing them. Be sure choke is off, and throttle is wide open during test. Compression should be at least 160 psi and should not vary more than 15% between cylinders.
All other models: These engines are equipped with an automatic compression release (ACR) mechanism. It is diffi cult to obtain an
accurate compression reading because of ACR mechanism. As an alternative, use cylinder leakdown test described below.
CYLINDER LEAKDOWN TEST
A cylinder leakdown test can be a valuable alternative to a compression test. By pressurizing combustion chamber from an external air source you can determine if valves or rings are leaking, and how badly.
Cylinder leakdown tester is a relatively simple, inexpensive leakdown tester for small engines. This tester includes a quick-connect for attaching adapter hose and a holding tool.
1. Run engine for 3-5 minutes to warm it up.
2. Remove spark plug(s) and air fi lter from engine.
3. Rotate crankshaft until piston (of cylinder being tested) is at top dead center (TDC) of compression stroke. Hold
engine in this position while testing. Holding tool supplied with tester can be used if PTO end of crankshaft is accessible. Lock holding tool onto crankshaft. Install a 3/8 in. breaker bar into hole/slot of holding tool, so it is perpendicular to both holding tool and crankshaft PTO.
If fl ywheel end is more accessible, use a breaker bar and socket on fl ywheel nut/screw to hold it in position. An
assistant may be needed to hold breaker bar during testing. If engine is mounted in a piece of equipment, it may be possible to hold it by clamping or wedging a driven component. Just be certain that engine cannot rotate off of TDC in either direction.
4. Install adapter into spark plug hole, but do not attach it to tester at this time.
5. Turn regulator knob completely counterclockwise.
6. Connect an air source of at least 50 psi to tester.
7. Turn regulator knob clockwise (increase direction) until gauge needle is in yellow set area at low end of scale.
8. Connect tester quick-connect to adapter hose. While fi rmly holding engine at TDC, gradually open tester valve.
Note gauge reading and listen for escaping air at combustion air intake, exhaust outlet, and crankcase breather.
Condition Conclusion
Air escaping from crankcase breather. Ring or cylinder worn. Air escaping from exhaust system. Defective exhaust valve/improper seating. Air escaping from intake. Defective intake valve/improper seating. Gauge reading in low (green) zone. Piston rings and cylinder in good condition. Gauge reading in moderate (yellow) zone. Engine is still usable, but there is some wear present.
Customer should start planning for overhaul or replacement.
Gauge reading in high (red) zone. Rings and/or cylinder have considerable wear. Engine
should be reconditioned or replaced.
1962 690 05 Rev. -- KohlerEngines.com
Page 20
Air Cleaner/Intake
AIR CLEANER
These systems are CARB/EPA certifi ed and components should not be altered or modifi ed in any way.
A
D
A Air Cleaner Housing B Inner Element C Retaining Clip D Element E End Cap F Dust Ejector Valve
NOTE: Operating engine with loose or damaged air
cleaner components could cause premature wear and failure. Replace all bent or damaged components.
NOTE: Paper element cannot be blown out with
compressed air.
1. Unhook retaining clips and remove end cap(s).
2. Check and clean inlet screen (if equipped).
3. Pull air cleaner element out of housing and replace. Check condition of inner element; replace when dirty.
4. Check all parts for wear, cracks, or damage, and that ejector area is clean.
5. Install new element(s).
6. Reinstall end cap(s) with dust ejector valve/screen down; secure with retaining clips.
C
B
E
F
BREATHER TUBE
Ensure both ends of breather tube are properly connected.
AIR COOLING
WARNING
Hot Parts can cause severe burns. Do not touch engine while operating or just
after stopping.
Never operate engine with heat shields or guards removed.
NOTE: Operating engine with a restricted air intake
screen or radiator, damaged/ broken fan assembly, or missing fan shroud will cause engine damage due to over heating.
Proper cooling is essential. To prevent over heating, clean screens, cooling fi ns, and other external surfaces of engine. Avoid spraying water at wiring harness or any electrical components. See Maintenance Schedule.
62 690 05 Rev. --KohlerEngines.com20
Page 21
EFI SYSTEM
WARNING
Explosive Fuel can cause fi res and severe burns.
Do not fi ll fuel tank while engine is hot or running.
Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.
Typical electronic fuel injection (EFI) system and related components include:
Fuel pump/module and lift pump.
Fuel lter.
High pressure fuel line.
Fuel line(s).
Fuel injectors.
Throttle body/intake manifold.
Electronic control unit (ECU).
Ignition coils.
Engine (oil) temperature sensor.
Throttle position sensor (TPS).
Crankshaft position sensor.
Oxygen sensor.
Manifold absolute pressure sensor (MAP).
Wire harness assembly & af liated wiring.
Malfunction indicator light (MIL) - optional.
Intake air temperature sensor.
FUEL RECOMMENDATIONS
Refer to Maintenance.
FUEL LINE
Low permeation fuel line must be installed on all Kohler Co. engines to maintain EPA and CARB regulatory compliance.
OPERATION
NOTE: When performing voltage or continuity tests,
avoid putting excessive pressure on or against connector pins. Flat pin probes are recommended for testing to avoid spreading or bending terminals.
EFI system is designed to provide peak engine performance with optimum fuel effi ciency and lowest possible emissions. Ignition and injection functions are electronically controlled, monitored and continually corrected during operation to maintain ideal air/fuel ratio.
Central component of system is Engine Control Unit (ECU) which manages system operation, determining best combination of fuel mixture and ignition timing for current operating conditions.
A lift fuel pump is used to move fuel from tank through an in-line fuel fi lter and fuel line. Fuel is then pumped to fuel pump module. Fuel pump module regulates fuel pressure to a system operating pressure of 39 psi. Fuel is delivered from fuel pump module through high pressure fuel line into injectors, which inject fuel into intake ports. ECU controls amount of fuel by varying length of time that injectors are on. This can range from 2 to over 12 milliseconds depending on fuel requirements. Controlled injection of fuel occurs every other crankshaft revolution, or once for each 4-stroke cycle. When intake valve opens, air/fuel mixture is drawn into combustion chamber,compressed, ignited, and burned.
ECU controls amount of fuel being injected and ignition timing by monitoring primary sensor signals for engine temperature, speed (RPM), and throttle position (load). These primary signals are compared to preprogrammed maps in ECU computer chip, and ECU adjusts fuel delivery to match mapped values. After engine reaches operating temperature, an exhaust gas oxygen sensor provides feedback to ECU based upon amount of unused oxygen in exhaust, indicating whether fuel mixture being delivered is rich or lean. Based upon this feedback, ECU further adjusts fuel input to re-establish ideal air/fuel ratio. This operating mode is referred to as closed loop operation. EFI system operates closed loop when all three of following conditions are met:
Oil temperature is greater than 50°C (122°F).
Oxygen sensor has warmed suf ciently to provide a
signal (minimum 400°C, 752°F).
Engine operation is at a steady state (not starting,
warming up, accelerating, etc.).
During closed loop operation ECU has ability to readjust temporary and learned adaptive controls, providing compensation for changes in overall engine condition and operating environment, so it will be able to maintain ideal air/fuel ratio. This system requires a minimum engine oil temperature greater than 60°C (140°F) to properly adapt. These adaptive values are maintained as long as ECU is not reset.
During certain operating periods such as cold starts, warm up, acceleration, high load, etc., a richer air/fuel ratio is required and system operates in an open loop mode. In open loop operation oxygen sensor output is used to ensure engine is running rich, and controlling adjustments are based on primary sensor signals and programmed maps only. This system operates open loop whenever three conditions for closed loop operation (above) are not being met.
ECU is brain or central processing computer of entire EFI system. During operation, sensors continuously gather data which is relayed through wiring harness to input circuits within ECU. Signals to ECU include: ignition (on/off), crankshaft position and speed (RPM), throttle position, oil temperature, intake air temperature, exhaust oxygen levels, manifold absolute pressure, and battery voltage.
2162 690 05 Rev. -- KohlerEngines.com
Page 22
EFI SYSTEM
ECU compares input signals to programmed maps in its memory to determine appropriate fuel and spark requirements for immediate operating conditions. ECU then sends output signals to set injector duration and ignition timing.
ECU continually performs a diagnostic check of itself, each of sensors, and system performance. If a fault is detected, ECU can turn on a Malfunction Indicator Light (MIL) (if equipped) on equipment control panel, store fault code in its fault memory, and go into a default operating mode. Depending on signifi cance or severity of fault, normal operation may continue. A technician can access stored fault code using a blink code diagnosis ashed out through MIL. An optional computer software diagnostic program is also available, see Tools and Aids.
ECU requires a minimum of 6.0 volts to operate. To prevent engine over-speed and possible failure, a
rev-limiting feature is programmed into ECU. If maximum RPM limit (4500) is exceeded, ECU suppresses injection signals, cutting off fuel fl ow. This process repeats itself in rapid succession, limiting operation to preset maximum.
Wiring harness used in EFI system connects electrical components, providing current and ground paths for system to operate. All input and output signaling occurs through two special all weather connectors that attach and lock to ECU. Connectors are Black and Grey and keyed differently to prevent being attached to ECU incorrectly.
Condition of wiring, connectors, and terminal connections is essential to system function and performance. Corrosion, moisture, and poor connections are as likely cause of operating problems and system errors as an actual component. Refer to Electrical System for additional information.
EFI system is a 12 VDC negative ground system, designed to operate down to a minimum of 6.0 volts. If system voltage drops below this level, operation of voltage sensitive components such as ECU, fuel pump, ignition coils, and injectors will be intermittent or disrupted, causing erratic operation or hard starting. A fully charged, 12 volt battery with a minimum of 350 cold cranking amps is important in maintaining steady and reliable system operation. Battery condition and state of charge should always be checked fi rst when troubleshooting an operational problem.
Keep in mind that EFI-related problems are often caused by wiring harness or connections. Even small amounts of corrosion or oxidation on terminals can interfere with milliamp currents used in system operation.
Cleaning connectors and grounds will solve problems in many cases. In an emergency situation, simply disconnecting and reconnecting connectors may clean up contacts enough to restore operation, at least temporarily.
If a fault code indicates a problem with an electrical component, disconnect ECU connector and test for continuity between component connector terminals and corresponding terminals in ECU connector using an ohmmeter. Little or no resistance should be measured, indicating that wiring of that particular circuit is OK.
Crankshaft position sensor is essential to engine operation; constantly monitoring rotation and speed (RPM) of crankshaft. There are 23 consecutive teeth cast into fl ywheel. One tooth is missing and is used to reference crankshaft position for ECU. Inductive crankshaft position sensor is mounted 0.20-0.70 mm (0.008-0.027 in.) from fl ywheel.
During rotation, an AC voltage pulse is created within sensor for each passing tooth. ECU calculates engine speed from time interval between consecutive pulses. Gap from missing tooth creates an interrupted input signal, corresponding to specifi c crankshaft position near BDC for cylinder #1. This signal serves as a reference for control of ignition timing by ECU. Synchronization of inductive speed pickup and crankshaft position takes place during fi rst two revolutions each time engine is started. Sensor must be properly connected at all times. If sensor becomes disconnected for any reason, engine will quit running.
Throttle position sensor (TPS) is used to indicate throttle plate angle to ECU. Since throttle (by way of governor) reacts to engine load, angle of throttle plate is directly related to load on engine.
Mounted on throttle body and operated directly off end of throttle shaft, TPS works as a potentiometer, varying voltage signal to ECU in direct correlation to angle of throttle plate. This signal, along with other sensor signals, is processed by ECU and compared to internal preprogrammed maps to determine required fuel and ignition settings for amount of load.
Correct position of TPS is established and set at factory. Do not loosen TPS or alter mounting position unless absolutely required by fault code diagnosis. If TPS is loosened or repositioned, appropriate TPS Learn Procedure must be performed to re-establish baseline relationship between ECU and TPS.
Engine (oil) temperature sensor is used by system to help determine fuel requirements for starting (a cold engine needs more fuel than one at or near operating temperature).
Mounted in crankcase next to breather cover, it has a temperature-sensitive resistor that extends into oil ow. Resistance changes with oil temperature, altering voltage sent to ECU. Using a table stored in its memory, ECU correlates voltage drop to a specifi c temperature. Using fuel delivery maps, ECU then knows how much fuel is required for starting at that temperature.
Intake Air Temperature (IAT) sensor is a thermally sensitive resistor that exhibits a change in electrical resistance with a change in its temperature.
When sensor is cold, resistance of sensor is high. As sensor warms up, resistance drops and voltage signal increases. From voltage signal, ECU can determine temperature of intake air.
Purpose of an air temperature sensor is to help ECU calculate air density. Higher air temperature less dense air becomes. As air becomes less dense ECU knows that it needs to lessen fuel fl ow to achieve correct air/fuel ratio. If fuel ratio was not changed engine would become rich, possibly losing power and consuming more fuel.
Oxygen sensor functions like a small battery, generating a voltage signal to ECU based upon difference in oxygen content between exhaust gas and ambient air.
22
62 690 05 Rev. --KohlerEngines.com
Page 23
EFI SYSTEM
Tip of sensor, protruding into exhaust gas, is hollow. Outer portion of tip is surrounded by exhaust gas, with inner portion exposed to ambient air. When oxygen concentration on one side of tip is different than that of other side, a voltage signal up to 1.0 volt is generated and sent to ECU. Voltage signal tells ECU if engine is straying from ideal fuel mixture, and ECU then adjusts injector pulse accordingly.
Oxygen sensor functions after being heated to a minimum of 400°C (752°F). A heater inside sensor heats electrode to optimum temperature in about 10 seconds. Oxygen sensor receives ground through wire, eliminating need for proper grounding through muffl er. If problems indicate a bad oxygen sensor, check all connections and wire harness. Oxygen sensor can also be contaminated by leaded fuel, certain RTV and/or other silicone compounds, fuel injector cleaners, etc. Use only those products indicated as O2 Sensor Safe.
Manifold absolute pressure (MAP) sensor provides immediate manifold pressure information to ECU. MAP measures difference in pressure between outside atmosphere and vacuum level inside intake manifold and monitors pressure in manifold as primary means of detecting load. Data is used to calculate air density and determine engine's mass air fl ow rate, which in turn determines required ideal fueling. MAP also stores instant barometric pressure reading when key is turned ON.
Fuel injectors mount into intake manifold, and high pressure fuel line attaches to them at top end. Replaceable O-rings on both ends of injector prevent external fuel leakage and also insulate it from heat and vibration. A special clip connects each injector to high pressure fuel line and holds it in place. O-rings and retaining clip must be replaced any time fuel injector is separated from its normal mounting position.
When key switch is on, fuel pump module will pressurize high pressure fuel line to 39 psi, and voltage is present at injector. At proper instant, ECU completes ground circuit, energizing injector. Valve needle in injector is opened electromagnetically, and pressure in high pressure fuel line forces fuel down through inside. Director plate at tip of injector contains a series of calibrated openings which directs fuel into manifold in a cone-shaped spray pattern.
Injectors have sequential fueling that open and close once every other crankshaft revolution. Amount of fuel injected is controlled by ECU and determined by length of time valve needle is held open, also referred to as injection duration or pulse width. Time injector is open (milliseconds) may vary in duration depending on speed and load requirements of engine.
A high-voltage, solid-state, battery ignition system is used with EFI system. ECU controls ignition output and timing through transistorized control of primary current delivered to coils. Based on input from crankshaft position sensor, ECU determines correct fi ring point for speed at which engine is running. At proper instant, it interrupts fl ow of primary current in coil, causing electromagnetic fl ux fi eld to collapse. Flux collapse induces an instantaneous high voltage in coil secondary which is strong enough to bridge gap on spark plug. Each coil fi res every other revolution.
EFI engines are equipped with either a 20 or 25 amp charging system to accommodate combined electrical demands of ignition system and specifi c application. Charging system troubleshooting information is provided in Electrical System.
An electric fuel pump module and a lift pump (two types) are used to transfer fuel in EFI system. Two types of lift pumps are: a pulse fuel pump or a low pressure electric fuel pump. Pumping action is created by either oscillation of positive and negative pressures within crankcase through a hose, or by direct lever/pump actuation off rocker arm movement. Pumping action causes diaphragm on inside of pump to pull fuel in on its downward stroke and to push it into fuel pump module on its upward stroke. Internal check valves prevent fuel from going backward through pump. Fuel pump module receives fuel from lift pump, increases and regulates pressure for fuel injectors.
Fuel pump module is rated for a minimum output of 13.5 liters per hour and regulated at 270 kilo pascals (39 psi).
When key switch is turned ON and all safety switch requirements are met, ECU activates fuel pump module for about six seconds, which pressurizes system for start-up. If key switch is not promptly turned to start position, engine fails to start, or engine is stopped with key switch ON (as in case of an accident), ECU switches off pump preventing continued delivery of fuel. In this situation, MIL will go on, but it will go back off after 4 cranking revolutions if system function is OK. Once engine is running, fuel pump remains on.
Precision components inside fuel pump module are not serviceable. DO NOT attempt to open fuel pump module. Damage to components will result and warranty will be void. Because fuel pump module is not serviceable, engines are equipped with a special 10-micron EFI fuel lter to prevent harmful contamination from entering module.
If there are two fi lters in system, one before lift pump will be a standard 51-75 micron fi lter, and one after lift pump will be special 10-micron fi lter. Be sure to use an approved 10-micron fi lter for replacement.
High pressure fuel line is an assembly of hoses, injector caps and a fuel connector to fuel pump module. High pressure fuel line feeds fuel to top of injectors through injector caps. Caps are fastened to intake manifold and injectors are locked into place. A small retaining clip provides a secondary lock.
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EFI SYSTEM
High pressure fuel line is serviced as a complete assembly to prevent tampering and safety hazards. Components are not individually serviceable.
Vent hose assembly is intended to vent fuel vapor out of fuel pump module and direct fuel vapor into throttle body. All EFI engines are equipped with an engine mounted purge port on #2 cylinder barrel baffl e. This capped purge port can be used by OEM to vent fuel tanks or used in conjunction with a carbon canister kit for Tier III evaporative emissions compliance. Purge port connects to vent hose assembly and directs all fuel vapor into throttle body. If purge port remains unused, port must remain capped to prevent dirt from entering engine.
EFI engines have no carburetor, so throttle function (regulate incoming combustion airfl ow) is achieved with a throttle valve in a separate throttle body attached to intake manifold. Throttle body/intake manifold provides mounting for fuel injectors, throttle position sensor, MAP sensor, intake air temperature sensor, high pressure fuel line, idle speed screw, and air cleaner assembly.
Idle speed is only adjustment that may be performed on EFI system. Standard idle speed setting for EFI engines is 1500 RPM, but certain applications might require a different setting. Check equipment manufacturer’s recommendation.
For starting and warm up, ECU will adjust fuel and ignition timing, based upon ambient temperature, engine temperature, and loads present. In cold conditions, idle speed will probably be different than normal for a few moments. Under other conditions, idle speed may actually start lower than normal, but gradually increase to established setting as operation continues. Do not attempt to circumvent this warm up period, or readjust idle speed during this time. Engine must be completely warmed up, in closed loop operating mode for accurate idle adjustment.
IMPORTANT NOTES!
Cleanliness is essential and must be maintained at all
times when servicing or working on EFI system. Dirt, even in small quantities, can cause signifi cant problems.
Clean any joint or fi tting with parts cleaning solvent
before opening to prevent dirt from entering system.
Always depressurize fuel system through fuel
connector on fuel pump module before disconnecting or servicing any fuel system components.
Never attempt to service any fuel system component
while engine is running or ignition switch is ON.
Do not use compressed air if system is open. Cover
any parts removed and wrap any open joints with plastic if they will remain open for any length of time. New parts should be removed from their protective packaging just prior to installation.
Avoid direct water or spray contact with system
components.
Do not disconnect or reconnect ECU wiring harness
connector or any individual components with ignition on. This can send a damaging voltage spike through ECU.
Do not allow battery cables to touch opposing
terminals. When connecting battery cables attach positive (+) cable to positive (+) battery terminal fi rst, followed by negative (-) cable to negative (-) battery terminal.
Never start engine when cables are loose or poorly
connected to battery terminals.
Never disconnect battery while engine is running.
Never use a quick battery charger to start engine.
Do not charge battery with key switch ON.
Always disconnect negative (-) battery cable before
charging battery, and also unplug harness from ECU before performing any welding on equipment.
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EFI SYSTEM
ELECTRICAL COMPONENTS Electronic Control Unit (ECU) Pinout of ECU
Black Connector
Pin # Function
1 Ignition Coil #1 Ground 2 Battery Ground 3 Diagnostic Communication Line 4 Speed Sensor input 5 Fuel Injector Output #1 Ground 6 Fuel Injector Output #2 Ground 7 Oxygen Sensor Heater 8 Intake Air Temperature (IAT) sensor input
9 Fuel Pump Ground 10 Ground for IAT, TPS, MAP, O2 and Oil Sensors 11 Manifold Absolute Pressure (MAP) sensor input 12 Throttle Position Sensor (TPS) input 13 Speed Sensor Ground 14 Oil Temperature Sensor input 15 Ignition Switch (Switched +12V) 16 Power for TPS and MAP Sensors (+5V) 17 Oxygen Sensor (O2) input 18 Battery Power (Permanent +12V)
Grey Connector
Pin # Description
1 Not Used 2 Not Used 3 Malfunction Indicator Light (MIL) Ground 4 Not Used 5 Not Used 6 GCU Tach Output 7 Not Used 8 Not Used
9 Battery Ground 10 Ignition Coil #2 Ground 11 Not Used 12 Not Used 13 Not Used 14 Safety Switch Ground 15 Not Used 16 ECU 17 Fuel Pump Control (+12V) 18 Not Used
Pinout of ECU
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EFI SYSTEM
Never attempt to disassemble ECU. It is sealed to prevent damage to internal components. Warranty is void if case is opened or tampered with in any way.
All operating and control functions within ECU are preset. No internal servicing or readjustment may be performed. If a problem is encountered, and you determine ECU to be faulty, contact your source of supply.
ECU pins are coated at factory with a thin layer of electrical grease to prevent fretting and corrosion. Do not attempt to remove grease from ECU pins.
Relationship between ECU and throttle position sensor (TPS) is very critical to proper system operation. If TPS or ECU is changed, or mounting position of TPS is altered, appropriate TPS Learn Procedure must be performed to restore synchronization.
Any service to ECU, TPS/Throttle Body (including idle speed increase over 300 RPM), or fuel pump module replacement should include ECU Reset.
This will clear all trouble codes, all closed loop learned offsets, all max values, and all timers besides permanent hour meter.
This system will NOT reset when battery is disconnected!
ECU Reset Procedure
1. Turn key/ignition OFF.
2. Install Red wire jumper from Kohler EFI service kit on to service port (connect white wire to black wire in 4 way diagnostic port).
3. Turn key/ignition ON, then OFF and count 10 seconds.
4. Turn key/ignition ON, then OFF and count to 10 seconds a second time.
5. Remove Red wire jumper. Turn key/ignition ON, then OFF and count to 10 seconds a third time. ECU is reset.
A TPS Learn Procedure must be performed after ECU Reset.
TPS Learn Procedure
1. Turn idle screw clockwise one full turn prior to key/ ignition ON after ECU Reset.
2. Start engine, run at low idle until engine is warm.
3. Idle speed must be above 1500 RPM. If below 1500 RPM, turn idle screw up to 1700 RPM and then shut down engine and perform ECU Reset again.
4. Adjust idle speed down to 1500 RPM. Allow engine to dwell at 1500 RPM for about 3 seconds.
5. After this, adjust idle speed to fi nal specifi ed speed setting.
6. Turn key/ignition OFF and count to 10 seconds.
Learn procedure is complete.
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EFI SYSTEM
Sensor
U
B
Intake Air
M G
T
G
S
AM
F
R
M
Q
V
A
M
K
C
I
B
AP
A
W
J
W
K
J
M
M
F
E
M
G L
L
M
M
H
F
D B
H
AJ
AI
AH
AG
AF
AE
AD
O Rectifi er-Regulator
Stator
Crankshaft Position
Temperature Sensor
AI
Sensor
Oil Temperature
EFI Oil Temperature
Manifold Absolute
Sensor (some models)
AH
AM
only
Pressure Sensor
Electronic Governor
AG
O
Wiring Diagram
AL
H
H
M
N
Y
AK
M B
B
B
F
B
G
X
AC
AB
AA
Z
A Red B Red/Black C Red/White D Yellow E Light Green
F Dark Green G Dark Blue H Purple I Pink J Ta n
K White L Grey M Black N
Throttle Position
P 30A Fuse Q Battery R Fuel Pump S 6-Terminal Connector T Starter Motor
Z Fuel Injector #1 AA Fuel Injector #2 AB Ignition Coil #1 AC Ignition Coil #2 AD
U Oil Pressure Switch V MIL W 10A Fuse X Black Connector Y Grey Connector
Sensor
AE Oxygen Sensor AF
AJ Diagnostic Connector AK Grey/Blue AL
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EFI SYSTEM
Crankshaft Position Sensor
A sealed, non-serviceable assembly. If Fault Code diagnosis indicates a problem within this area, test and correct as follows.
1. Remove #2 side cylinder shroud to access. Check mounting and air gap of sensor. It must be 0.20-0.70 mm (0.008-0.027 in.).
2. Inspect wiring and connections for damage or problems.
3. Make sure engine has resistor type spark plugs.
4. Disconnect Black connector from ECU.
5. Connect an ohmmeter between #4 and #13 pin terminals. A resistance value of 325-395 Ω at room temperature (20°C, 68°F) should be obtained. If resistance is correct, check mounting, air gap, ywheel teeth (damage, run-out, etc.), and fl ywheel key.
6. Disconnect crankshaft position sensor connector from wiring harness. Test resistance between terminals. A reading of 325-395 Ω should again be
obtained.
a. If resistance is incorrect, remove screws securing
sensor to mounting bracket and replace sensor.
b. If resistance in step 5 was incorrect, but
resistance of sensor alone was correct, test wire harness circuits between sensor connector terminals and corresponding pin terminals (#4 and #13) in main connector. Correct any observed problem, reconnect sensor, and perform step 5 again.
7. When fault is corrected and engine starts, clear fault codes following ECU Reset procedure.
Throttle Position Sensor (TPS) Resistance Table
Throttle
Position
Closed A & C 1400-1800 Yes
Full with
Stop Pin
Full without
Stop Pin
Any A & B 3000-7000 Yes
TPS is a sealed, non-serviceable assembly. If diagnosis indicates a bad sensor, complete replacement is necessary. If a blink code indicates a problem with TPS, it can be tested as follows:
1. Counting number of turns, back out idle speed adjusting screw (counterclockwise) until throttle plates can be closed completely. Write this number down for reference later.
2. Disconnect Black connector from ECU, but leave TPS mounted to throttle body.
3. a. Use an ohmmeter and connect red (positive)
ohmmeter lead to Black pin 12 terminal and black (negative) ohmmeter lead to Black pin 10 terminal to test.
Between Terminal
A & C 3200-4100 Yes
A & C 4600-5200 Yes
Resistance
Value (Ω)
Continuity
b. Hold throttle closed and check resistance. It
should be 1400-1800 Ω.
4. Leave leads connected to pin terminals as described in step 3. Rotate throttle shaft slowly to full throttle position. Monitor dial during rotation for indication of any momentary short or open circuits. Note resistance at full throttle position. It should be 4600-5200 Ω without a stop pin, or 3200-4100 Ω with a stop pin.
5. Disconnect main wiring harness connector from TPS, leaving TPS assembled to throttle body. Refer to Resistance Table and perform resistance checks indicated between terminals in TPS switch, with throttle in positions specifi ed.
If resistance values in steps 3, 4, and 5 are within
specifi cations, go to step 6.
If resistance values are not within specifi cations, or a
momentary short or open circuit was detected during rotation (step 4), TPS needs to be replaced, go to step 7.
6. Check TPS circuits (input, ground) between TPS plug and main harness connector for continuity, damage, etc. Input pin is 12 and ground is pin 10.
a. Repair or replace as required. b. Turn idle speed screw back in to its original
setting.
c. Reconnect connector plugs, start engine and
retest system operation.
7. #1 side fuel injector electrical connector may be removed to access fastening screws. Remove two mounting screws from TPS. Save screws for reuse. Remove and discard faulty TPS. Install replacement TPS and secure with original mounting screws.
a. Reconnect Black and TPS connector plugs.
Reconnect electrical connector to #1 side fuel injector.
b. Perform TPS Learn Procedure integrating new
sensor to ECU.
Engine (Oil) Temperature Sensor
A sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem with temperature sensor, it can be tested as follows:
1. Remove temperature sensor from crankcase and cap or block sensor hole.
2. Wipe sensor clean and allow it to reach room temperature (25°C, 77°F).
3. Unplug Black connector from ECU.
4. With sensor still connected, check temperature sensor circuit resistance between Black pin 10 and 14 terminals. Value should be 9000-11000 Ω.
5. Unplug sensor from wire harness and check sensor resistance separately across two pins. Resistance value should again be 9000-11000 Ω.
a. If resistance is out of specifi cations, replace
temperature sensor.
b. If it is within specifi cations, proceed to Step 6.
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EFI SYSTEM
6. Check circuits (input, ground), from wire harness connector to sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 14 in wire harness connector (as in step 4). Connect other lead to terminal #1 in sensor plug. Continuity should be indicated. Repeat test between Black pin 10 and terminal #2 in sensor plug.
Intake Air Temperature Sensor
A non-serviceable component. Complete replacement is required if it is faulty. Sensor and wiring harness can be checked as follows. Carefully unseat both clips securing main fuel line to air cleaner bracket to access sensor.
1. Remove temperature sensor from throttle body.
2. Allow it to reach room temperature (20°C, 68°F).
3. Unplug Black connector from ECU.
4. With sensor still connected, check temperature sensor circuit resistance between Black pin 10 and 8 pin terminals. Value should be 3100-3900 Ω.
5. Unplug sensor from wire harness and check sensor resistance separately across two pins. Resistance value should again be 3100-3900 Ω.
a. If resistance is out of specifi cations, replace
temperature sensor.
b. If it is within specifi cations, proceed to Step 6.
6. Check circuits (input, ground), from main harness connector to sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 8 in main harness connector (as in step 4). Connect other lead to terminal #1 in sensor plug. Continuity should be indicated. Repeat test between Black pin 10 and terminal #2 in sensor plug.
7. Reinstall sensor and reposition main fuel line back into clips on air cleaner bracket.
Oxygen Sensor (O2)
Components
Pin A
Pin D
Cutaway Oxygen Sensor Components (O2)
Pin B
Pin C
D
E
A
B
A Protection Shield B
C Lower Insulator D
E Upper Insulator F
G
Temperature must be controlled very accurately and gas constituents measured to a high degree of accuracy for absolute sensor measurements. This requires laboratory equipment to determine a good or bad sensor in fi eld. Furthermore, as with most devices, intermittent problems are diffi cult to diagnose. Still, with a good understanding of system and sensor, it is possible to diagnose many sensor problems in fi eld.
Using diagnostic software connected to ECU is a useful technique for observing sensor performance. However, user must understand that such software reads a signal generated by ECU. If there is an ECU or wiring problem, readings could be misinterpreted as a sensor problem. Digital nature of signal to software means that it is not reading continuous output of sensor. A voltmeter can also be used as an effective tool in diagnosing sensors. It is advisable to use an electronic meter such as a digital voltmeter. Simple mechanical meters may place a heavy electrical load on sensor and cause inaccurate readings. Since resistance of sensor is highest at low temperatures, such meters will cause largest inaccuracies when sensor is in a cool exhaust.
Visual Inspection
1. Look for a damaged or disconnected sensor-to­engine harness connection.
2. Look for damage to sensor lead wire or associated engine wiring due to cutting, chaffi ng or melting on a hot surface.
3. Disconnect sensor connector and look for corrosion in connector.
4. Try reconnecting sensor and observe if problem has cleared.
5. Correct any problems found during visual check.
High Temp
Water Seal
C
F
Planar Element
and Heater
Stainless Steel
Housing
Terminal Connection
to Element
G
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EFI SYSTEM
Sensor Signal Observation NOTE: Do not cut into or pierce sensor or engine
wiring to make this connection. Sensor
produces a very small signal. Corrosion or damage to wiring could lead to an incorrect signal because of repairs or contamination to sensor.
1. Using a voltmeter or diagnostic software observe voltage before engine is started. With key ON, voltage should read about 1.0 volt. This voltage is generated by ECU. If it is not present, disconnect sensor and observe voltage at harness connector. If voltage is now present, there is a short in sensor or associated wiring and corrective action should be taken. If voltage still is not present, there is a problem with ECU or engine harness.
2. Reconnect sensor and start engine. Run engine at suffi cient speed to bring sensor up to operating temperature. Maintain for 1 to 2 minutes to ensure that engine has gone closed loop. Once in closed loop, sensor voltage should cycle between about 100 to 250 mv (low speed idle) and 700 to 900 mv (high speed no load). If this cycling is not observed, a determination must be made, if problem is with engine or sensor.
3. Check engine harness for battery voltage on heater circuit.
Removal Inspection
NOTE: Apply anti-seize compound only to threads.
Anti-seize compound will affect sensor performance if it gets into lower shield of sensor.
1. If sensor has heavy deposits on lower shield, engine, oil, or fuel may be source.
2. If heavy carbon deposits are observed, incorrect engine fuel control may be occurring.
3. If sensor is at room temperature, measure between signal leads, black wire (Pin C) and grey wire (Pin D) attached to sensor. If resistance is less than one megohm, sensor has an internal short.
4. With sensor at room temperature measure heater circuit resistance, purple wire (Pin A) and white wire (Pin B), resistance should be 8.1-11.1 Ω.
5. If a damaged sensor is found, identify root cause, which may be elsewhere in application. Refer to Troubleshooting-Oxygen Sensor (O2) table.
6. A special "dry to touch" anti-seize compound is applied to all new oxygen sensors at factory. If recommended mounting thread sizes are used, this material provides excellent anti-seize capabilities and no additional anti-seize is needed. If sensor is removed from engine and reinstalled, anti-seize compound should be reapplied. Use an oxygen sensor safe type anti-seize compound. It should be applied according to directions on label.
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Troublshooting-Oxygen Sensor (O2)
Condition Possible Cause Conclusion
Low voltage output. Shorted sensor or sensor circuit.
Shorted lead wire. Wiring shorted to ground.
Contamination of air reference. Remove source of external
Air leak at sensor or gasket, sensor upper shield damage.
High voltage output. Silica poisoning. Replace sensor.
Contaminated gasoline. Use high quality fuel. Engine problem; misfi re. Correct cause of misfi re. Excessive rich air/fuel ratio. Check for high fuel pressure
Wiring shorted to voltage. Repair wiring.
Open circuit, no activity from sensor. Broken element.
Sensor dropped. Hard blow to engine or exhaust
system. Defective sensor. Thermal shock.
Slow time response. Open heater circuit.
Improper handling. Carbon deposits.
Improper fueling. Correct fueling. Incorrect or contaminated fuel. Use high quality fuel. Excessive engine oil consumption
causing exhaust contamination or other exhaust side contamination.
Heater circuit open/shorted or out of specifi cation.
Manifold Absolute Pressure Sensor (MAP)
A sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem with manifold absolute pressure sensor, it can be tested as follows:
1. Make sure all connections are making proper contact and are free of dirt and debris. Remove blower housing. Slide locking tab out and pull off manifold absolute pressure connector. Turn key switch to ON and check with a volt meter by contacting red lead to pin 1 and black lead to pin 2. There should be 5 volts present, indicating ECU and wiring harness are functioning.
2. Check continuity in wire harness. Ohms between Pin 3 at sensor connector and Black pin 11 connector at ECU should be near zero ohms. If no continuity is measured or very high resistance, replace wire harness.
3. Check to make sure intake manifold is not loose and MAP sensor is not loose. Loose parts would allow a vacuum leak, making MAP sensor report misleading information to ECU.
a. Tighten all hardware and perform an ECU Reset
and a TPS Learn Procedure to see if MIL will display a fault with MAP sensor again. If MIL fi nds a fault with MAP sensor, replace it.
Replace sensor or repair wiring.
contamination, protect air reference area.
Use recommended torque at installation, replace gasket or sensor.
Revise application exhaust. Shield sensor from damage.
Leaking injector Liquid fuel in vent line
Replace sensor.
Replace sensor.
Correct engine condition.
Repair short in harness wires, replace sensor.
EFI SYSTEM
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EFI SYSTEM
Fuel Injectors
WARNING
Explosive Fuel can cause fi res and severe burns.
Fuel system ALWAYS remains under HIGH PRESSURE.
Wrap a shop towel completely around fuel pump module connector. Press release button(s) and slowly pull connector away from fuel pump module allowing shop towel to absorb any residual fuel in high pressure fuel line. Any spilled fuel must be completely wiped up immediately.
Details
B
C
E
F
H
A Electrical Connection B Upper O-ring C Solenoid Winding D Armature E Valve Housing F Valve Seat
G Valve End H Lower O-ring
I Director Plate
NOTE: Do not apply voltage to fuel injector(s).
Excessive voltage will burn out injector(s). Do not ground injector(s) with ignition ON. Injector(s) will open/turn on if relay is energized.
NOTE: When cranking engine with injectors
disconnected, fault codes will be registered in ECU and will need to be cleared using software fault clear or an ECU Reset and TPS Learn Procedure.
Injector problems typically fall into three general categories: electrical, dirty/clogged, or leakage. An electrical problem usually causes one or both of injectors to stop functioning. Several methods may be used to check if injectors are operating.
1. With engine running at idle, listen for a buzzing or clicking sound.
A
D
G
I
2. Disconnect electrical connector from an injector and listen for a change in idle performance (only running on one cylinder) or a change in injector noise or vibration.
If an injector is not operating, it can indicate either a bad injector, or a wiring/electrical connection problem. Check as follows:
1. Disconnect electrical connector from both injectors. Plug a 12 volt noid light into one connector.
2. Make sure all safety switch requirements are met. Crank engine and check for fl ashing of test light. Turn key OFF for at least 10 seconds between tests to allow ECU to go to sleep and reawake. Repeat test at other connector.
a. If fl ashing occurs, use an ohmmeter (Rx1 scale)
and check resistance of each injector across two terminals. Proper resistance is 11-13 Ω. If injector resistance is correct, check whether connector and injector terminals are making a good connection. If resistance is not correct, replace injector.
Check all electrical connections, connectors, and wiring harness leads if resistance is incorrect.
Injector leakage is very unlikely, but in those rare instances it can be internal (past tip of valve needle), or external (weeping around injector O-rings). Loss of system pressure from leakage can cause hot restart problems and longer cranking times. To check for leakage it will be necessary to loosen or remove blower housing which may involve removing engine from unit. Refer to Disassembly for removal of injector.
1. Remove manifold mounting bolts and separate throttle body/manifold from engine leaving TPS, high pressure fuel line, injectors and fuel line connections intact. Discard old gaskets.
2. Position manifold assembly over an appropriate container to capture fuel and turn key switch ON to activate fuel pump and pressurize system. Do not turn switch to START position.
NOTE: Fuel pump module pins are coated with a thin
layer of electrical grease to prevent fretting and corrosion. Do not attempt to remove electrical grease from fuel pump module pins.
3. If either injector exhibits leakage of more than two to four drops per minute from tip, or shows any sign of leakage around outer shell, turn ignition switch OFF and replace injector as follows.
4. Depressurize fuel system.
5. Clean any dirt accumulation from sealing/mounting area of faulty injector(s) and disconnect electrical connector(s).
6. Pull retaining clip off top of injector(s). Remove screw holding injector(s) from manifold.
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EFI SYSTEM
7. Reverse appropriate procedures to install new injector(s) and reassemble engine. Use new O-rings and retaining clips any time an injector is removed (new replacement injectors include new O-rings and retaining clips). Lubricate O-rings lightly with clean engine oil. Use installation tool provided with O-rings to install new upper O-ring. Place tool into fuel injector inlet. Place one side of O-ring into O-ring groove and roll O-ring over tool onto fuel injector. Torque screw securing fuel injector caps and blower housing mounting screws to 7.3 N·m (65 in. lb.), and intake manifold and air cleaner mounting screws to
10.5 N·m (93 in. lb.). An ECU Reset will need to be completed.
Injector problems due to dirt or clogging are generally unlikely due to design of injectors, high fuel pressure, and detergent additives in gasoline. Symptoms that could be caused by dirty/clogged injectors include rough idle, hesitation/stumbling during acceleration, or triggering of fault codes related to fuel delivery. Injector clogging is usually caused by a buildup of deposits on director plate, restricting fl ow of fuel, resulting in a poor spray pattern. Some contributing factors to injector clogging include higher than normal operating temperatures, short operating intervals, and dirty, incorrect, or poor quality fuel. Cleaning of clogged injectors is not recommended; they should be replaced. Additives and higher grades of fuel can be used as a preventative measure if clogging has been a problem.
Ignition Coil
If a coil is determined to be faulty, replacement is necessary. An ohmmeter may be used to test wiring and coil windings.
NOTE: Do not ground primary coil with ignition ON as
they may overheat or spark.
NOTE: Always disconnect spark plug lead from spark
plug before performing following tests.
NOTE: If ignition coil(s) are disabled and an ignition
fault is registered, system will automatically disable corresponding fuel injector drive signal. Fault must be corrected to ignition coil
and ECU power (switch) must be turned OFF for 10 seconds for injector signal to return. This is a safety measure to prevent bore washing and oil dilution.
Testing
Using an ohmmeter set on Rx1 scale, check resistance in circuits as follows:
1. To check cylinder coil 1 (starter side), disconnect Black connector from ECU and test between Black pins 1 and 15. To check cylinder coil 2 (oil fi lter side), disconnect Grey connector from ECU and test between Grey pins 10 and 17. Wiring and coil primary circuits are OK if readings are 0.5-0.8 
2. If reading(s) are not within specifi ed range, check and clean connections and retest.
3. If reading(s) are still not within specifi ed range, test coils separately from main harness as follows:
a. Remove screw retaining coil to housing and
disconnect primary leads connector.
b. Connect an ohmmeter set on Rx1 scale to
primary terminals of coil. Primary resistance should be 0.5-0.8 Ω.
c. Connect an ohmmeter set on Rx10K scale
between spark plug boot terminal and B+ primary terminal. Secondary resistance should be 6400­7800 Ω.
d. If secondary resistance is not within specifi ed
range, coil is faulty and needs to be replaced.
FUEL COMPONENTS
WARNING
Explosive Fuel can cause fi res and severe burns.
Fuel system ALWAYS remains under HIGH PRESSURE.
Wrap a shop towel completely around fuel pump module connector. Press release button(s) and slowly pull connector away from fuel pump module allowing shop towel to absorb any residual fuel in high pressure fuel line. Any spilled fuel must be completely wiped up immediately.
Fuel Pump
Fuel pump module is not serviceable and must be replaced if determined to be faulty. If a fuel pump problem is suspected, make certain pump is being activated, all electrical connections are properly secured, fuses are good, and a minimum of 7.0 volts is being supplied. If during cranking, voltage drops below 7.0 volts, a reduction of fuel pressure may occur resulting in a lean starting condition. If required, testing of fuel pump may be conducted.
1. Relieve fuel pressure at fuel pump module. Fuel pump module may need to be loosened or pulled away from engine. Disconnect fuel coupler from fuel pump module and insert pressure test jumper (from Kohler EFI Service Kit) between high pressure fuel line and fuel pump module.
2. Connect black hose of Pressure Tester. Route clear hose into a portable gasoline container or equipment fuel tank.
3. Turn on key switch to activate pump and check system pressure on gauge. It may take several key cycles to compress air introduced into system and reach regulated pressure. If system pressure of 39 psi ± 3 is observed, wiring, fuel pump, and regulator are working properly. Turn key switch OFF and depress valve button on tester to relieve system pressure.
a. If pressure is too high or too low, replace fuel
pump module.
4. If pump did not activate (step 3), disconnect plug from fuel pump. Connect a DC voltmeter across terminals in plug, turn on key switch and observe if a minimum of 7 volts is present during six second prime process.
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EFI SYSTEM
5. If no voltage is observed, connect red lead of meter to red wire of plug and black lead to a good ground while key is still ON.
6. If voltage is between 7 and 14, turn key switch OFF and connect an ohmmeter between terminals on pump to check for continuity.
a. If there was no continuity between pump terminals, replace fuel pump. b. If voltage was below 7, test wiring harness.
7. If voltage at plug was good, and there was continuity across pump terminals, reconnect plug to pump, making sure you have a good connection. Turn on key switch and listen for pump to activate.
a. If pump starts, repeat steps 2 and 3 to verify correct pressure. b. If pump still does not operate, replace it.
High Pressure Fuel Line
High pressure fuel line is mounted to bracket on intake manifold and #2 side baffl es. No specifi c servicing is required unless operating conditions indicate that it needs replacement. Thoroughly clean area around all joints and relieve any pressure before starting any disassembly. Detach by removing two mounting screws, wire ties, and injector retaining clips.
Purge Port and Vent Hose Assembly
No specifi c servicing is required for vent hose assembly or purge port unless operating conditions indicate replacement is required. All components are serviced individually. Abrasion sleeves on hoses should be reused or replaced when servicing vent hoses. Please note vent hose routing and replicate after service or component replacement to prevent pinching or abrasion of vent hoses. Only Kohler replacement parts can be used because fi tting is specifi c to system and must be maintained. Visit KohlerEngines.com for recommended Kohler replacement parts.
Throttle Body/Intake Manifold Assembly
NOTE: ECU Reset is required if throttle body is replaced. Throttle body is serviced as an assembly, with throttle shaft, TPS, throttle plate, and idle speed adjusting screw
installed. Throttle shaft rotates on needle bearings (non-serviceable), capped with seals to prevent air leaks.
TROUBLESHOOTING
Troubleshooting Guide
Condition Possible Cause
Fuel pump not running.
Faulty spark plugs.
Old/stale fuel.
Incorrect fuel pressure.
Crankshaft position sensor loose or faulty.
Engine Starts Hard
or Fails to Start
When Cold.
TPS set incorrect (ECU Reset and TPS Learn).
TPS faulty.
Engine temp sensor faulty.
Faulty coils.
Low system voltage.
Faulty injectors.
Faulty battery.
Loose or corroded connections.
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Troubleshooting Guide
Condition Possible Cause
Faulty spark plugs.
Fuel pump not running.
Fuel pressure low.
Engine Starts Hard
or Fails to Start
When Hot.
Engine Stalls or
Idles Roughly
(cold or warm).
Engine Misses,
Hesitates, or Stalls
Under Load.
Low Power
Insuffi cient fuel delivery.
TPS set incorrect (ECU Reset and TPS Initialization).
Crankshaft position sensor loose or faulty.
TPS faulty.
Engine temp sensor faulty.
Faulty injectors.
Faulty spark plugs.
Insuffi cient fuel delivery.
TPS set incorrect.
TPS faulty.
Faulty engine temperature sensor.
Faulty injectors.
Fuel injector(s), fuel fi lter, fuel line, or fuel pick-up dirty/restricted.
Dirty air cleaner.
Insuffi cient fuel pressure or fuel delivery.
Vacuum (intake air) leak.
Improper governor setting, adjustment or operation.
TPS faulty, mounting problem or TPS Initialization Procedure incorrect.
Bad coil(s), spark plug(s), or wires.
Faulty/malfunctioning ignition system.
Dirty air fi lter.
Insuffi cient fuel delivery.
Improper governor adjustment.
Plugged/restricted exhaust.
One injector not working.
Basic engine problem exists.
TPS faulty or mounting exists.
Throttle plate in throttle body not fully opening to WOT stop (if equipped).
EFI SYSTEM
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EFI SYSTEM
Function Test
WARNING
High Pressure Fluids can puncture skin and cause severe injury or death.
Do not work on fuel system without proper training or safety equipment.
Fluid puncture injuries are highly toxic and hazardous. If an injury occurs, seek immediate medical attention.
Function of fuel system is to provide suffi cient delivery of fuel at system operating pressure of 39 psi ± 3. If an engine starts hard, or turns over but will not start, it may indicate a problem with EFI fuel system. A quick test will verify if system is operating.
1. Disconnect and ground spark plug leads.
2. Complete all safety interlock requirements and crank engine for approximately 3 seconds.
3. Remove spark plugs and check for fuel at tips.
a. If there is fuel at tips of spark plugs fuel pump and
injectors are operating.
b. If there is no fuel at tips of spark plugs, check
following:
1. Make sure fuel tank contains clean, fresh,
proper fuel.
2. Make sure that vent in fuel tank is open.
3. Make sure fuel tank valve (if equipped) is fully
opened.
4. Make sure battery is supplying proper voltage.
5. Check that fuses are good, and that no
electrical or fuel line connections are damaged or broken.
6. Test fuel pump module operation as described
earlier under Fuel Pump.
Fault Codes Example of Diagnostic Display
One second pause
(1)
One second pause
One second pause
(7)
Three second pause
(6)
One second pause
(1)
(0)
(0)
End Code 61
Fault
Code
0107
Diagnostic Fault Code Summary
Fault Code Connection or Failure Description
0031 Oxygen Sensor Heater Circuit High Voltage 0032 Oxygen Sensor Heater Circuit Low Voltage 0107 Manifold Absolute Pressure Sensor Circuit Low Voltage or Open 0108 Manifold Absolute Pressure Sensor Circuit High Voltage 0112 Intake Air Temperature Sensor Circuit Low Voltage 0113 Intake Air Temperature Sensor Circuit High Voltage or Open 0117 Coolant/Oil Temperature Sensor Circuit Low Voltage 0118 Coolant/Oil Temperature Sensor Circuit High Voltage or Open 0122 Throttle Position Sensor Circuit Low Voltage or Open 0123 Throttle Position Sensor Circuit High Voltage 0131 Oxygen Sensor 1 Circuit Low Voltage, or Open 0132 Oxygen Sensor 1 Circuit High Voltage 0171 Maximum Adaptation Limit Exceeded 0172 Minimum Adaptation Limit Exceeded 0174 Lean Fuel Condition at High Load (Open Loop) 0201 Injector 1 Circuit Malfunction 0202 Injector 2 Circuit Malfunction
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0230 Fuel Pump Module Circuit Low Voltage or Open 0232 Fuel Pump Module Circuit High Voltage 0336 Crankshaft Position Sensor Noisy Signal 0337 Crankshaft Position Sensor No Signal 0351 Cylinder 1 Ignition Coil Malfunction 0352 Cylinder 2 Ignition Coil Malfunction 0562 System Voltage Low 0563 System Voltage High 1693 Tach Output (ECU) Low 1694 Tach Output (ECU) High
61 End of Code Transmission
ECU continuously monitors engine operation against preset performance limits. If operation is outside limits, ECU activates MIL, if equipped, and stores a diagnostic code in its fault memory. If component or system returns to proper function, ECU will turn off MIL. If MIL stays illuminated, it warns customer a fault is currently happening, and dealer service is required. Upon receipt, dealer technician can access fault code(s) to help determine what portion of system is malfunctioning.
Codes are accessed through key switch and displayed as blinks or fl ashes of MIL. Access codes as follows:
1. Check that battery voltage is above 11 volts.
2. Start with key switch OFF.
3. Turn key switch to ON and OFF, then ON and OFF,
then ON, leaving it on in third sequence. Do not start engine. Time between sequences must be less than
2.5 seconds.
4. MIL will blink a series of times. Number of times MIL
blinks represents a number in blink code.
5. A sequence of four digits make up a fault code.
There is a one (1) second pause between blinks of a fault code. There is a three (3) second pause between separate fault codes. After fault code(s) are blinked a two digit 61 is blinked to indicate program has completed.
a. It’s a good idea to write down codes as they
appear, as they may not be in numerical sequence.
b. Code 61 will always be last code displayed,
indicating end of code transmission. If code 61 appears immediately, no other fault codes are present.
After problem has been corrected, fault codes may be cleared by following ECU Reset and TPS Learn Procedures.
Diagnostic Fault Code Summary lists fault codes, and what they correspond to. Diagnostic Code Summary is a list of individual codes with an explanation of what triggers them, what symptoms might be expected, and probable causes.
EFI SYSTEM
A MIL may not be provided with engine. If equipment manufacturer has not added a MIL to equipment, one can be added easily for quick diagnostics. Main engine to vehicle connection will have a tan wire which is ground for MIL. Either incandescent or LED type bulbs can be used for MIL as long as they do not draw more than 0.1 amps. Bulb needs to be rated at 1.4 Watts or less, or needs to have a total resistance of 140 Ω or more. LEDs typically draw less than 0.03 amps. Attach +12 volts to positive terminal of bulb and attach ground terminal of bulb to tan wire.
Diagnostic Code Summary Code 0031
Component: Oxygen Sensor Heater Fault: O2S Heater Circuit High Voltage Condition: System voltage too high, shorted
connection or faulty sensor.
Conclusion: Oxygen Sensor Related
Sensor connector or wiring problem.
Sensor damaged.
Pin circuit wiring or connectors at Black
7.
ECU Related
ECU-to-harness connection problem.
Code 0032
Component: Oxygen Sensor Heater Fault: O2S Heater Circuit Low Voltage Condition: System voltage too low, open connection
or faulty sensor.
Conclusion: Engine Wiring Harness Related
Pin circuit wiring or connectors. ECU black pin 7 or broken wire.
Oxygen Sensor Related
Sensor connector or wiring problem.
Poor system ground from ECU to engine or battery to engine.
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EFI SYSTEM
Code 0107
Component: Manifold Absolute Pressure Sensor Fault: MAP Circuit Low Voltage or Open Condition: Intake manifold leak, open connection or
faulty sensor.
Conclusion: MAP Sensor Related
Sensor malfunction.
Vacuum leaks from loose manifold or
sensor.
Wire Harness Related
Poor grounding or open circuit.
Wire harness and connectors loose,
damaged or corroded.
Pin circuit wiring or connectors at Black
10, 11 and 16.
Bad TPS Learn.
Code 0108
Component: Manifold Absolute Pressure Sensor Fault: MAP Circuit High Voltage Condition: Intake manifold leak, shorted connection
or faulty sensor.
Conclusion: MAP Sensor Related
Sensor malfunction.
Vacuum leaks from loose manifold or
sensor.
Wire Harness Related
Poor grounding.
Pin circuit wiring or connectors at Black
11.
Bad TPS Learn.
Code 0112
Component: Intake Air Temperature Sensor Fault: Intake Air Temperature Sensor Circuit
Low Voltage
Condition: Shorted connection, faulty sensor or
shorted wire.
Conclusion: Temperature Sensor Related
Sensor wiring or connection.
Engine Wiring Harness Related
Pin circuits Black 10 and Black 8 may
be damaged or routed near noisy signal (coils, alternator, etc.).
ECU-to-harness connection problem.
Code 0113
Component: Intake Air Temperature Sensor Fault: Intake Air Temperature Sensor Circuit
High Voltage or Open
Condition: Shorted connection, faulty sensor, broken
wire or connection.
Conclusion: Temperature Sensor Related
Sensor wiring or connection.
Engine Wiring Harness Related
Pin circuits ECU Black pin 10 and 8
may be damaged.
ECU-to-harness connection problem or
broken wire.
Code 0117
Component: Coolant/Oil Sensor Fault: Coolant/Oil Temperature Sensor Circuit
Low Voltage
Condition: Shorted connection, faulty sensor or
shorted wire.
Conclusion: Temperature Sensor Related
Sensor wiring or connection.
Engine Wiring Harness Related
Pin circuits Black 10 and Black 14
maybe damaged or routed near noisy signal (coils, stator, etc.).
ECU-to-harness connection problem.
Code 0118
Component: Coolant/Oil Sensor Fault: Coolant/Oil Temperature Sensor Circuit
High Voltage or Open
Condition: Shorted connection, faulty sensor, open
connection or broken wire.
Conclusion: Temperature Sensor Related
Sensor wiring or connection.
Engine Wiring Harness Related
Pin circuits ECU Black pin 10 and 14
may be damaged.
ECU-to-harness connection problem or
broken wire.
System Related
Engine is operating above 176°C
(350°F) temperature sensor limit.
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EFI SYSTEM
Code 0122
Component: Throttle Position Sensor (TPS) Fault: TPS Circuit Low Voltage or Open Condition: Open connection, broken wire or faulty
sensor.
Conclusion: TPS Related
TPS bad or worn internally.
Engine Wiring Harness Related
Broken or shorted wire in harness. ECU Black pin 10 to TPS pin 1. ECU Black pin 12 to TPS pin 3. ECU Black pin 16 to TPS pin 2.
Throttle Body Related
Throttle shaft inside TPS worn, broken,
or damaged.
Throttle plate loose or misaligned.
Throttle plate bent or damaged
allowing extra airfl ow past, or restricting movement.
ECU Related
Circuit providing voltage or ground to
TPS damaged.
TPS signal input circuit damaged.
Code 0123
Component: Throttle Position Sensor (TPS) Fault: TPS Circuit High Voltage Condition: Shorted connection or faulty sensor. Conclusion: TPS Sensor Related
Sensor connector or wiring.
Sensor output affected or disrupted by
dirt, grease, oil, wear.
Sensor loose on throttle body manifold.
Code 0131
Component: Oxygen Sensor Fault: O2S 1 Circuit Low Voltage Condition: Open connection, broken wire or faulty
sensor.
Conclusion: Oxygen Sensor Related
Sensor connector or wiring problem.
Sensor contaminated, corroded or
damaged.
Poor ground path.
Pin circuit wiring or connectors.
ECU Black pin 10 or 17.
TPS Learn Procedure Incorrect
Lean condition (check oxygen sensor
signal with VOA and see Oxygen Sensor section).
Engine wiring harness related such as a cut wire, broken or pinched.
Code 0132
Component: Oxygen Sensor Fault: O2S 1 Circuit High Voltage Condition: Shorted connection or faulty sensor. Conclusion: Oxygen Sensor Related
Sensor connector or wiring problem.
Sensor contaminated or damaged.
Poor ground path.
Pin circuit wiring or connectors.
ECU Black pin 10 or Black pin 17.
Engine Wiring Harness Related
Difference in voltage between sensed
voltage and actual sensor voltage.
Short in wire harness.
Throttle Body Related
Throttle shaft or bearings worn/
damaged.
Engine Wiring Harness Related
ECU pins Black 10, 12 and 16
damaged (wiring, connectors).
ECU pins Black 10, 12 and 16 routed
near noisy electrical signal (coils, alternator).
Intermittent 5 volt source from ECU
(pin Black 16).
ECU-to-harness connection problem.
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EFI SYSTEM
Code 0171
Component: Fuel System Fault: Maximum adaptation limit exceeded Condition: Fuel inlet screen/fi lter plugged, low
pressure at high pressure fuel line, TPS malfunction, shorted connection, faulty sensor, low fuel or wrong fuel type.
Conclusion: Oxygen Sensor Related
Corrosion or poor connection.
Sensor contaminated or damaged.
Air leak into exhaust.
Poor ground path.
Pin circuit wiring or connectors.
ECU Black pin 10 or Black pin 17.
TPS Sensor Related
Throttle plate position incorrect during
Learn procedure.
TPS problem or malfunction.
Engine Wiring Harness Related
Difference in voltage between sensed
voltage and actual sensor voltage.
Problem in wiring harness.
ECU-to-harness connection problem.
Systems Related
Ignition (spark plug, plug wire, ignition
coil).
Fuel (fuel type/quality, injector, fuel
pressure too low, fuel pump module or lift pump).
Combustion air (air cleaner dirty/
restricted, intake leak, throttle bores).
Base engine problem (rings, valves).
Exhaust system leak (muf er, ange,
oxygen sensor mounting boss, etc.).
Fuel in crankcase oil.
Code 0172
Component: Fuel System Fault: Minimum adaptation limit exceeded Condition: Too high pressure at high pressure fuel
line, TPS malfunction, shorted connection, faulty sensor or fuel pump module failure.
Conclusion: Oxygen Sensor Related
Sensor connector or wiring.
Sensor contaminated or damaged.
Poor ground path.
Pin circuit wiring or connectors.
ECU Black pin 10 or 17.
TPS Sensor Related
Throttle plate position incorrect during
Learn procedure.
TPS problem or malfunction.
Engine Wiring Harness Related
Difference in voltage between sensed
voltage and actual sensor voltage.
Problem in wiring harness.
ECU-to-harness connection problem.
Systems Related
Ignition (spark plug, plug wire, ignition
coil).
Fuel (fuel type/quality, injector, fuel
pressure too high, fuel pump module or lift pump).
Combustion air (air cleaner dirty/
restricted).
Base engine problem (rings, valves).
Fuel in crankcase oil.
Fuel pump module is over lled.
Lift pump diaphragm is ruptured.
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EFI SYSTEM
Code 0174
Component: Fuel System Fault: Lean fuel condition Condition: Fuel inlet screen/fi lter plugged, low
pressure at high pressure fuel line, TPS malfunction, shorted connection or faulty sensor.
Conclusion: TPS Learn Incorrect
Lean condition (check oxygen sensor
signal with VOA and see Oxygen Sensor).
Engine Wiring Harness Related
Pin circuit wiring or connectors. ECU pin Black 10, 12, 16 and 17.
Low Fuel Pressure
Plugged lters.
Bad lift pump.
Oxygen Sensor Related
Sensor connector or wiring problem.
Exhaust leak.
Poor ground.
Poor system ground from ECU to engine, causing rich running while indicating lean.
Fuel pump module connection. See Fuel Components.
Code 0201
Component: Fuel Injector Fault: Injector 1 Circuit Malfunction Condition: Injector damaged or faulty, shorted or
open connection.
Conclusion: Injector Related
Injector coil shorted or opened.
Code 0202
Component: Fuel Injector Fault: Injector 2 Circuit Malfunction Condition: Injector damaged or faulty, shorted or
open connection.
Conclusion: Injector Related
Injector coil shorted or opened.
Engine Wiring Harness Related
Broken or shorted wire in harness. ECU pin Black 6.
Wiring from Ignition.
ECU Related
Circuit controlling injector #2 damaged.
Code 0230
Component: Fuel Pump Fault: Circuit Low Voltage or Open Condition: Shorted or open connection. Conclusion: Fuel Pump Related
Fuel pump module open or shorted
internally.
Engine Wiring Harness related
Broken or shorted wire in harness. ECU pin Black 9 or Grey 17.
ECU Related
ECU is damaged.
Code 0232
Component: Fuel Pump Fault: Circuit High Voltage Condition: Shorted connection. Conclusion: Fuel Pump Related
Fuel pump module damaged internally.
Engine Wiring Harness Related
Broken or shorted wire in harness. ECU pin Black 5.
Wiring from Ignition.
ECU Related
Circuit controlling injector #1 damaged.
Charging Output System Too High.
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EFI SYSTEM
Code 0336
Component: Crankshaft Position Sensor Fault: Crankshaft Position Sensor Noisy Signal Condition: Air gap incorrect, loose sensor, faulty/bad
battery, shorted or faulty connection, faulty sensor or faulty sensor grounding.
Conclusion: Crankshaft Position Sensor Related
Sensor connector or wiring.
Sensor loose or air gap incorrect.
Crankshaft Position Sensor Wheel Related
Damaged teeth.
Gap section not registering.
Engine Wiring Harness Related
Pin circuit wiring or connectors. ECU pin Black 4 and Black 13.
ECU-to-harness connection problem.
Ignition System Related
Non-resistor spark plug(s) used.
Faulty or disconnected ignition coil or
secondary lead.
Code 0337
Component: Crankshaft Position Sensor Fault: Crankshaft Position Sensor No Signal Condition: Air gap incorrect, loose sensor, open or
shorted connection or faulty sensor.
Conclusion: Crankshaft Position Sensor Related
Sensor connector or wiring.
Sensor loose or air gap incorrect.
Crankshaft Position Sensor Wheel Related
Damaged teeth.
Engine Wiring Harness Related
Pin circuit wiring or connectors. ECU pin Black 4 or Black 13.
ECU-to-harness connection problem.
Code 0352
Component: Ignition Coil Fault: Cylinder 2 Ignition Coil Malfunction Condition: Broken wire in harness (may not be
visible), shorted connection or faulty sensor.
Conclusion: Engine Wiring Harness Related
Connection to ignition or fuse.
Pin circuit wiring or connectors.
ECU pin Grey 10.
ECU-to-harness connection problem.
Ignition System Related
Incorrect spark plug(s) used.
Poor connection to spark plug.
Code 0562
Component: System Voltage Fault: System Voltage Low Condition: Faulty voltage regulator, bad fuse or
shorted connection.
Conclusion: Corroded Connections
Bad Stator
Bad Battery
Low output charging system.
Poor magnet in ywheel.
Bad or missing fuse.
Code 0563
Component: System Voltage Fault: System Voltage High Condition: Faulty voltage regulator or shorted
connection.
Conclusion: Faulty Rectifi er-Regulator
Bad Stator.
Bad Battery.
If code is stored in fault history and starts normally. Clear code, no other service required.
Code 0351
Component: Ignition Coil Fault: Cylinder 1 Ignition Coil Malfunction Condition: Broken wire in harness (may not be
visible), shorted connection or faulty sensor.
Conclusion: Engine Wiring Harness Related
Connection to ignition or fuse.
Pin circuit wiring or connectors.
ECU pin Black 1.
ECU-to-harness connection problem.
Ignition System Related
Incorrect spark plug(s) used.
Poor connection to spark plug.
42
Code 1693
Component: Tach Output (ECU) Fault: Tach Circuit Low Condition: Tachometer output circuit short to ground. Conclusion: Bad Tach Wire (grounded).
GCU circuit short to ground.
Code 1694
Component: Tach Output (ECU) Fault: Tach Circuit High Condition: Tachometer output circuit short to battery. Conclusion: ECU or GCU circuit error.
Code 61
Component: End of Code Transmission
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EFI SYSTEM
Troubleshooting Flow Chart
Following fl ow chart provides an alternative method of troubleshooting EFI system. Chart will enable you to review entire system in about 10-15 minutes. Using chart, accompanying diagnostic aids (listed chart), and any signaled fault codes, you should be able to quickly locate any problems within system.
Flow Chart Diagnostic Aids
Diagnostic Aid #1 SYSTEM POWER
(MIL does not illuminate when key is turned ON) NOTE: MIL is installed by vehicle OEM. Twelve volt
supply to bulb will be part of vehicle wire harness. Kohler key switch model will have MIL on engine with 12V supply to bulb.
Conclusion
Battery
Main system fuse
MIL light bulb burned out
MIL electrical circuit problem
Pin circuits Grey 3.
Ignition switch
Permanent ECU power circuit problem
Pin circuit Black 18.
Switched ECU power circuit problem Pin circuit Black 15.
ECU grounds
ECU
Diagnostic Aid #2 FAULT CODES
Refer to Diagnostic Fault Code Summary.
Diagnostic Aid #3 RUN/ON
(MIL remains ON while engine is running)*
Condition
NOTE: Either incandescent or LED type bulbs can be
used for MIL as long as they do not draw more than 0.1 amps. Bulb needs to be rated at 1.4 Watts or less, or needs to have a total resistance of 140 Ω or more. LEDs typically draw less than
0.03 amps.
All current fault codes will turn on MIL when engine is running.
Diagnostic Aid #4 CRANKSHAFT POSITION SENSOR
(MIL does not turn off during cranking)
Condition
Crankshaft position sensor
Crankshaft position sensor circuit problem, pin circuits
Black 4 and Black 13.
Crankshaft position sensor/toothed wheel air gap
Toothed wheel
Flywheel key sheared
ECU
Diagnostic Aid #6 IGNITION SYSTEM
(no spark)
Condition
Spark plug
Plug wire
Coil
Coil circuit(s), pin circuits Grey 10 and Black 1.
ECU grounds
ECU
Vehicle safety interlocks, ground signal on safety wire.
Diagnostic Aid #7 FUEL SYSTEM ELECTRICAL
(no fuel delivery)
Condition
No fuel
Air in high pressure fuel line
Fuel valve shut OFF
Fuel lter/line plugged
Injector circuit(s), pin circuits Black 5 and Black 6
Injector
ECU grounds
ECU
Lift pump not working
Diagnostic Aid #8 FUEL SYSTEM
(fuel pressure)
Low Fuel Pressure-Condition
Low fuel
Fuel lter plugged
Fuel supply line plugged
Lift fuel pump - insuf cient fuel supply
Fuel pump (lift or module) - internally plugged
Low Fuel Pressure-Condition
Pressure regulator not functioning properly inside fuel
pump module.
Diagnostic Aid #9 BASIC ENGINE
(cranks but will not run)
Condition
Refer to basic engine troubleshooting charts within
Troubleshooting, Electronic Fuel Injection System and Electrical System.
Diagnostic Aid #5 FUEL PUMP
(fuel pump not turning on)
Condition
Main fuse
Fuel pump circuit problem, pin circuits Black 9 and
Grey 17.
Fuel pump module
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EFI SYSTEM
EFI Diagnostic Flow Diagram
START OF TEST
KEY ON
PROCEED TO START OF TEST FOR RETEST
MALFUNCTION
INDICATOR LIGHT
ON
ARE FAULT CODES
PRESENT?
NO
DOES ENGINE START?
NO
CRANK ENGINE.
DOES MIL GO OFF?
YES
KEY OFF AND KEY ON
LISTEN FOR FUEL PUMP.
DOES FUEL PUMP CYCLE
ON THEN OFF AFTER 1–2
SECONDS
YES
WHILE CRANKING, CHECK
IGNITION SYSTEM
1
2
?
YES MIL GOES OFF?
.
YES
NO
NO
YES
NO
NO
REFER TO DIAGNOSTIC AID #1
SYSTEM POWER
DIAGNOSTIC FAULT CODE SUMMARY
CRANKSHAFT POSITION SENSOR
REFER TO
CLEAR CODES
REFER TO DIAGNOSTIC AID #3
OPERATE AT VARIOUS SPEED/
REFER TO DIAGNOSTIC AID #4
REFER TO DIAGNOSTIC AID #5
RUN/ON
LOAD CONDITIONS
ARE FAULT CODES
PRESENT?
NO
END OF TEST
FUEL PUMP
REFER TO DIAGNOSTIC
YES
FAUL T CODE SUMMAR Y
CLEAR CODES
PROCEED TO START OF TEST FOR RETEST
SPARK?
YES
WHILE CRANKING, CHECK
INJECTOR FUEL DELIVERY.
WET SPARK PLUG?
YES
INSTALL IN-LINE PRESSURE
GAUGE AND KEY ON.
FUEL PRESSURE
IN SPECIFICATION?
1. After turning key to OFF, wait 10 seconds before turning to ON to allow ECU to go to sleep.
2. Fuel pump module can be heard or a vibration can be felt to establish pump cycle. Fuel pump module will run for one 4-6 second cycle when ECU wakes up after being asleep.
44
YES
NO
NO
NO
REFER TO DIAGNOSTIC AID #6
IGNITION SYSTEM
REFER TO DIAGNOSTIC AID #7
FUEL SYSTEM ELECTRICAL
REFER TO DIAGNOSTIC AID #8
FUEL SYSTEM
REFER TO DIAGNOSTIC AID #9
BASIC ENGINE
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GOVERNOR
These engines are equipped with an electronic governor or a mechanical governor.
ELECTRONIC GOVERNOR Components
A
D
E
Governor System
B
J
Governor Control
A
E Connector F
I Throttle Linkage J
Electronic governor regulates engine speed at varying loads. Typical electronic governor includes:
Digital linear actuator (DLA).
Throttle linkage.
Linkage spring.
Linkage retaining clip.
Governor control unit (GCU).
Digital Linear Actuator (DLA)
Energizing bi-directional digital linear actuator coils in proper sequence, causes threaded shaft to move out of, or back into rotor, in precise linear increments. When power is removed, actuator shaft remains in position. DLA must initialize (fully extend) to move throttle plate to closed position, and partially open for starting. Correct adjustment of DLA is critical to achieve full range of throttle plate movement. See Adjustment.
Unit (GCU)
F
H
G
I
B
Digital Linear
Actuator (DLA)
Throttle Body
Assembly
Plastic Linkage
Retaining Clip
A
B
C
DLA Throttle Plate
C
G
Governor control unit (GCU) senses engine speed by pulse voltage inputs from EFI ECU module. GCU regulates engine speed by variable input voltage from a customer-supplied source.
NOTE: Actual speeds depend on application. Refer to
Potentiometer Specifi cations
Mounting Screws
Throttle Body Lever
Adapter
equipment manufacturer’s recommendations.
Wiper Voltage Engine Speed (RPM)
0-1 Low Speed Endpoint
1-9 Variable Speed Endpoint
9-16 High Speed Endpoint
D Wiring Harness
H Linkage Spring
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Page 46
Governor System
Linkage
NOTE: Throttle linkage spring must be in place and
installed correctly to ensure proper throttle operation and performance.
Throttle linkage spring will fully open throttle plate if linkage becomes detached from DLA. This will create an overspeed condition causing engine to shut down. DLA shaft will have to be manually screwed back into body, and then retracted before reassembling linkage.
Adjustment
DLA Details
B
B
A
C
A
E
G
F
D
C
4. Place clevis shaft into actuator. Rotate clevis shaft clockwise 3 full turns, applying slight pressure, until you feel clevis shaft keyway make contact with key in actuator. When clevis shaft is installed properly at of clevis will be aligned with two mounting holes.
NOTE: Continuing to rotate clevis shaft after it has
made contact with keyway will damage keyway or actuator.
5. Confi rm that key and keyway are in alignment, by hand, press clevis shaft into actuator. It will take a reasonable amount of pressure to do this. If shaft will not move inward, do not force it. Remove clevis shaft and repeat previous step.
6. Reinstall DLA into bracket, torque screws to 7.3 N·m (65 in. lb.), and connect linkage.
GCU/Harness Diagnostics and Troubleshooting
NOTE: It is important to use proper sized probes to
perform these tests. Probes that are incorrect size can damage connector or harness plug.
Ground and Power Tests
1. Switch key to OFF position.
2. Remove GCU from bracket and unplug wiring harness.
These two tests check for power and ground supply to GCU. If either test fails, check if harness, electrical connections, or electrical system need repair.
A DLA B Mounting Holes
C Clevis D Keyway
E Clevis Shaft F Rubber Boot
G Keys
DLA must be in fully retracted position during assembly. Full range of throttle plate movement will not be achieved if DLA is partially extended when assembled. Loosen DLA mounting plate screws located on side of actuator plate. With throttle linkage secured with a retaining clip at end of DLA shaft, slide DLA bracket assembly back until throttle plate is fully open. Torque mounting plate screws to 10.2 N·m (90 in. lb.).
Proper link/spring assembly is critical. Insert spring hook tab of spring through DLA clevis hole until it exits opposite side, and tab of spring is allowed to snap into position. Hook opposite “hook” end of spring through throttle body lever adapter hole before inserting z-bend of link into throttle body lever adapter. Pay close attention not to stretch/over extend spring or damage to spring may occur.
If clevis shaft becomes overextended or disconnected from actuator reinstall as follows:
1. Disconnect linkage and remove DLA from bracket.
2. Remove clevis shaft completely out of DLA.
3. Reinstall rubber boot onto DLA if required.
Test 1 Probe Location
A
A Probe Location for Ground Test 1.
Test 1: Identify probe location in connector. Using a continuity tester, check for a good ground. If ground is faulty, inspect unit ground, battery ground, connectors, and wiring harness. Clean or fi x connections or replace any faulty parts.
If test 1 checks OK, locate probe location in connector, and check using test 2.
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Page 47
Governor System
Test 2 Probe Location
A
A Probe Location for Voltage Test 2.
Test 2: Identify probe location in connector. Using a 12 volt meter test for voltage. Turn key switch to ON position. Voltage should be within +/- 1 volt of battery voltage. If voltage is within +/- 1 volt of battery voltage, harness is OK, replace GCU. If not within +/- 1 volt of battery voltage, check connections and replace wiring harness if necessary.
Ohms Tests
1. Remove GCU from bracket and unplug wiring harness.
These two tests are for measuring resistance of DLA circuit that sends a signal to GCU. If either test fails, DLA is no good and should be replaced. If both tests are good, DLA is neither shorted or open, it is good. Another component, connection, or input is most likely at fault.
Test 2 Probe Location
A
A Probe Locations for OHMs Test 2.
Test 2: Identify probe locations in connector. Using a digital multi-meter set to lowest scale (0-200 ohms), place probes onto harness making sure of a good connection. Resistance should be between 47.7 and
58.3 ohms. If either test 1 or 2 fail resistance test, fault could also
be caused by a break/cut in wiring harness. Inspect and test for a potential harness issue prior to replacing DLA assembly.
Speed Control Input
Test 1 Probe Location
A
A Probe Locations for OHMs Test 1.
Test 1: Identify probe locations in connector. Using a digital multi-meter set to lowest scale (0-200 ohms), place probes onto harness making sure of a good connection. Resistance should be between 47.7 and
58.3 ohms.
If test 1 checks OK, locate wire ends in connector and check using test 2.
A
A Red Wire with Yellow Tracer.
This connection is a single wire red with yellow tracer.
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Page 48
Governor System
GCU Blink Code Tests
A
A Green LED Light B Yellow LED Light
GCU Blink Codes for Software Stored Codes - Activated when key is turned to ON position.
Failure Condition Possible Causes Response
Speed Error BLINKS ON
Watchdog Interrupt RFI interference Ground to kill,
Overspeed (Over 4500 RPM for 0.5 seconds sustained)
Excessive Battery Voltage (> 18v for
0.5 seconds)
B
Overtemp
Software bug
Lightning
External noise on ECU input Ground to kill,
Frozen throttle plate
DLA failure
Mechanical bindage
Open battery voltage on B+ 24 V battery (not compatible with system, 12 V battery only)
Speed control issues can also be diagnosed utilizing on-board Blink Code diagnostic lights equipped in GCU. These GCUs store blink codes/trouble codes, that can be quickly diagnosed using blink code charts.
close throttle plate
close throttle plate
Ground to kill, close throttle plate
Response
Time
1 second delay
0.5 seconds
LED Diagnostics
Yellow LED Green LED
BLINKS BLINKS
ON ON
OFF ON
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Page 49
Governor System
GCU Blink Codes for Software Running Codes - Activated when engine is running.
Response
Failure Condition Possible Causes Response
Running Normally None BLINKS BLINKS
RPM Too High Mechanical bindage None ON BLINKS
RPM Too Low Mechanical bindage None ON BLINKS
Missing Pulse (Normal RPM)
Missing Pulse (RPM Too High)
Missing Pulse (RPM Too Low)
Sleep Mode Power at GCU with no ECU
Watchdog Interrupt RFI interference Ground to kill,
Overspeed (Over 4500 RPM for 0.5 seconds sustained)
Excessive Battery Voltage (> 18v for
0.5 seconds)
Faulty ECU Faulty ECU wiring
Faulty ECU Faulty ECU wiring
Faulty ECU Faulty ECU wiring
System shutdown 30 minutes OFF OFF
pulses (left in run mode)
Overtemp
Software bug
Lightning
External noise on ECU input
Frozen throttle plate
DLA failure
Mechanical bindage 1 second
Open battery voltage on B+ 24 V battery (not compatible with system, 12 V battery only)
close throttle plate
Ground to kill, close throttle plate
Time
N/A BLINKS OFF
delay
0.5 seconds
LED Diagnostics
Yellow LED Green LED
BLINKS ON
ON ON
OFF ON
ON OFF
OFF OFF
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Page 50
Governor System
Electronic Governor Troubleshooting Flow Chart
Turn off key switch.
Do Not Touch Digital Linear Actuator (DLA)
NOTE: DLA is not a solenoid. It is a precision electronic motor. Do not exert force to center clevis shaft!
Visually inspect DLA and Linkage. See illustrations on page 45.
Confi rm that:
Fail if
Pass if
1. Clevis shaft and boot in place.
2. Clip attached.
3. DLA wire attached.
Clevis shaft and boot are out of DLA.
Arm and boot installation as follows, see illustrations on pages 45 and 46.
1. Remove DLA from bracket.
2. Pull clevis shaft completely out of DLA.
3. Reinstall boot on DLA if required.
4. Do Not push or force clevis shaft into body, it must fi rst be threaded and correctly aligned. Improper installation can permanently damage DLA.
5. Lightly insert clevis shaft into body of DLA.
6. Thread 3 full turns or until you feel internal key touch. Flat surface clevis should be in alignment with DLA mounting holes.
7. Firmly push DLA to bottom.
8. Connect clip.
9. Connect wire.
Proper link/spring assembly is critical. Insert spring
Start/test run unit for engine speed control operation.
Fail
hook tab of spring through DLA clevis hole until it exits opposite side, and tab of spring is allowed to snap into position (see page 45). Hook opposite "hook" end of spring through throttle lever hole before inserting z-bend of link into throttle lever. Pay close attention not to stretch/over extend spring or damage to spring may occur.
Pass
Go to 12 Volt Power Test on next page.
50 62 690 05 Rev. --KohlerEngines.com
Test control system of equipment. Refer to Equipment Manufacturer’s diagnostic procedures for control system.
Page 51
Governor System
Electronic Governor Troubleshooting Flow Chart Continued
Locate Speed Control input wire. This connection is a single wire red with yellow tracer.
12 Volt Power Test
Start engine in normal manner as described in Owner’s Manual. (Engine will initially operate at speed it was last run or shut down, then will go to idle).
See illustration on page 47.
Unplug and connect a jumper wire to red wire with a yellow tracer on engine wire harness.
Attach open end of jumper wire to positive (+) battery terminal.
Engine speed increases (if it was at low speed).
Fail
Engine speed does not change.
Review GCU blink codes with chart on page 49 to identify if a system condition is present.
Proceed to Ground/Power and OHMs test for GCU. Refer to page 46.
Remove GCU and unplug wiring harness. See illustration on page 45.
GCU Circuit Test.
Pass
Operation Input Voltage: 0-1 Volts at Idle/9+ Volts at High Speed.
Kohler electronic governor system tests OK. Test control system of equipment. Refer to Equipment Manufacturer’s diagnostic procedures for control system.
Inspect wiring harness for broken wire or bad connections. (Repair/Replace as required).
Test supply ground circuit to GCU using a continuity OHM/tester. Refer to page 46.
Continued on next page
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Governor System
Electronic Governor Troubleshooting Flow Chart Continued
Turn key switch to ON position. Test supply voltage to GCU using volt meter. Refer to page 47 (battery voltage +/- 1 volt) Note: Prevent Damage to Connector. Do Not Use Oversized Probe Tips.
Proceed to DLA Circuit Test.
Test 1: Identify wire ends in connector. Using a digital multi-meter set to lowest scale (0-200 ohms) place probes onto harness making sure of a good connection. Resistance should be between 47.7 and 58.3 ohms. Refer to page 47.
Test 2: Identify wire ends in connector. Using a digital multi-meter set to lowest scale (0-200 ohms) place probes onto harness making sure of a good connection. Resistance should be between 47.7 and 58.3 ohms. Refer to page 47.
If either test fails, DLA is no good and should be replaced. If both tests are good, DLA is neither shorted or open, and should be good. Another component, connection, or input is most likely at fault.
Basic Electrical Diagram of Electronic Governor System
B+
10
8
12
13
Power
Device Ground
Speed Signal
Green LED Light
Yellow LED Light
DLA Driver Controls
14
*
*
1 2 6 7
ECU Speed Output (speed signal)
ECU
2B
2A
1A
1B
Application Supplied Speed Control Input
Operation Input Voltage: 0-1 Volts at Idle/9+ Volts at High Speed
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DLA
Page 53
Governor System
MECHANICAL GOVERNOR
Governed speed setting is determined by position of throttle control. It can be variable or constant, depending on engine application.
Governor is designed to hold engine speed constant under changing load conditions. Governor gear/fl yweight mechanism is mounted inside crankcase and is driven off gear on camshaft.
Components
I
J
K
J
K
Inside Engine
A Throttle Lever B Control Bracket C Throttle Linkage D Linkage Spring
E Governor Gear Shaft F Governor Lever G Governor Spring H Idle Spring
I Governor Gear J Flyweight K Regulating Pin
This governor design works as follows:
Centrifugal force acting on rotating governor gear assembly causes fl yweights to move outward as speed
increases. Governor spring tension moves them inward as speed decreases.
As yweights move outward, they cause regulating pin to move outward.
Regulating pin contacts tab on cross shaft causing shaft to rotate.
One end of cross shaft protrudes through crankcase. Rotating action of cross shaft is transmitted to throttle lever of
throttle body through external linkage.
When engine is at rest, and throttle is in FAST position, tension of governor spring holds throttle plate open. When
engine is operating, governor gear assembly is rotating. Force applied by regulating pin against cross shaft tends to close throttle plate. Governor spring tension and force applied by regulating pin balance each other during operation, to maintain engine speed.
When load is applied and engine speed and governor gear speed decreases, governor spring tension moves
governor lever to open throttle plate wider. This allows more fuel into engine, increasing engine speed. As speed reaches governed setting, governor spring tension and force applied by regulating pin will again offset each other to hold a steady engine speed.
B
C
D
A
E
F
G
H
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Page 54
Governor System
Governor Adjustments
NOTE: Do not tamper with governor setting. Overspeed is hazardous and could cause personal injury.
Initial Adjustment Procedure
Make this adjustment whenever governor arm is loosened or removed from cross shaft. Adjust as follows:
1. Make sure throttle linkage is connected to governor arm and throttle lever on throttle body.
2. Loosen nut holding governor lever to cross shaft.
3. Move governor lever toward throttle body as far as it will go (wide open throttle) and hold in this position.
4. Insert a long thin rod or tool into hole on cross shaft and rotate shaft counterclockwise (viewed from end) as far as it will turn, then torque nut to 7.1 N·m (63 in. lb.).
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Page 55
Lubrication System
This engine uses a full pressure lubrication system which delivers oil under pressure to crankshaft, camshaft, connecting rod bearing surfaces, and hydraulic valve lifters.
A high-effi ciency gerotor oil pump maintains high oil fl ow and oil pressure, even at low speeds and high operating temperatures. A pressure relief valve limits maximum pressure of system. Oil pan must be removed to service oil pickup, pressure relief valve, and oil pump.
Lubrication Components
D
A
C
G
F
I
A Oil Filter B Back Side C Oil Cooler D Cylinder Shroud E Oil Drain Plug
F Oil Fill Tube G Oil Fill/Dipstick H Pressure Switch I
OIL RECOMMENDATIONS
Refer to Maintenance.
CHECK OIL LEVEL
NOTE: To prevent extensive engine wear or damage,
never run engine with oil level below or above operating range indicator on dipstick.
Ensure engine is cool. Clean oil fi ll/dipstick areas of any debris.
1. Remove dipstick; wipe oil off.
2. Reinsert dipstick into tube; rest cap on tube, do not
thread cap onto tube.
3. Remove dipstick; check oil level. Level should be at
top of indicator on dipstick.
4. If oil is low on indicator, add oil up to top of indicator
mark.
5. Reinstall and secure dipstick.
CHANGE OIL AND FILTER
Change oil while engine is warm.
1. Clean area around oil fi ll cap/dipstick and drain plug.
2. Clean area around oil fi lter; remove fi lter; wipe off
3. Place new fi lter in shallow pan with open end up. Fill
4. Apply a thin fi lm of clean oil to rubber gasket on new
5. Refer to instructions on oil fi lter for proper
6. Fill crankcase with new oil. Level should be at top of
7. Reinstall oil fi ll cap/dipstick and tighten securely.
8. Start engine; check for oil leaks. Stop engine; correct
9. Dispose of used oil and fi lter in accordance with
E
B
Oil Temperature
Switch
Remove drain plug and oil fi ll cap/dipstick. Allow oil to drain completely.
mounting surface. Reinstall drain plug and torque to
21.4 N·m (16 ft. lb.).
with new oil until oil reaches bottom of threads. Allow 2 minutes for oil to be absorbed by fi lter material.
lter.
installation.
indicator on dipstick.
leaks. Recheck oil level.
local ordinances.
B
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Page 56
Lubrication System
OIL COOLER
NOTE: Oil cooler is mounted under cylinder shroud.
Removal of cylinder shroud is necessary to access oil cooler.
1. Clean fi ns with a brush or compressed air.
2. Remove screws securing oil cooler and tilt to clean back side.
3. Reinstall oil cooler and torque to 2.3 N·m (21 in. lb.).
OIL SENTRY
(if equipped)
This switch is designed to prevent engine from starting in a low oil or no oil condition. Oil Sentry™ may not shut down a running engine before damage occurs. In some applications this switch may activate a warning signal. Read your equipment manuals for more information.
Oil Sentry™ pressure switch is installed in oil pan pressure port. On engines not equipped with Oil Sentry™ installation hole is sealed with a 1/8-27 N.P.T.F. pipe plug.
Installation
1. Apply pipe sealant with Tefl on® (Loctite® PST® 592™ Thread Sealant or equivalent) to threads of switch.
2. Install switch into tapped hole in oil pan.
3. Torque switch to 10.7 N·m (95 in. lb.).
Testing
Compressed air, a pressure regulator, pressure gauge, and a continuity tester are required to test switch.
1. Connect continuity tester across blade terminal and metal case of switch. With 0 psi pressure applied to switch, tester should indicate continuity (switch closed).
2. Gradually increase pressure to switch. As pressure increases through range of 7-11 psi tester should indicate a change to no continuity (switch open). Switch should remain open as pressure is increased to 90 psi maximum.
3. Gradually decrease pressure through range of 7-11 psi. Tester should indicate a change to continuity (switch closed) down to 0 psi.
4. Replace switch if it does not operate as specifi ed.
62 690 05 Rev. --KohlerEngines.com56
Page 57
Electrical System
SPARK PLUGS
CAUTION
Electrical Shock can cause injury. Do not touch wires while engine is running.
Spark Plug Component and Details
A
B
C
Inspection
Inspect each spark plug as it is removed from cylinder head. Deposits on tip are an indication of general condition of piston rings, valves, and carburetor.
Normal and fouled plugs are shown in following photos:
Normal
Plug taken from an engine operating under normal conditions will have light tan or gray colored deposits. If center electrode is not worn, plug can be set to proper gap and reused.
Worn
D
A Wire Gauge B Spark Plug C Ground Electrode D Gap
NOTE: Do not clean spark plug in a machine using
abrasive grit. Some grit could remain in spark plug and enter engine causing extensive wear and damage.
Engine misfi re or starting problems are often caused by a spark plug that has improper gap or is in poor condition.
Engine is equipped with following spark plugs:
Gap 0.76 mm (0.03 in.) Thread Size 14 mm Reach 19.1 mm (3/4 in.) Hex Size 15.9 mm (5/8 in.)
Refer to Maintenance for Repairs/Service Parts.
Service
Clean out spark plug recess. Remove plug and replace.
1. Check gap using wire feeler gauge. Adjust gap to
0.76 mm (0.03 in.).
2. Install plug into cylinder head.
3. Torque plug to 27 N·m (20 ft. lb.).
On a worn plug, center electrode will be rounded and gap will be greater than specifi ed gap. Replace a worn spark plug immediately.
Wet Fouled
A wet plug is caused by excess fuel or oil in combustion chamber. Excess fuel could be caused by a restricted air cleaner, a carburetor problem, or operating engine with too much choke. Oil in combustion chamber is usually caused by a restricted air cleaner, a breather problem, worn piston rings, or valve guides.
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Page 58
Electrical System
Carbon Fouled
Soft, sooty, black deposits indicate incomplete combustion caused by a restricted air cleaner, over rich carburetion, weak ignition, or poor compression.
Overheated
BATTERY
A 12-volt battery with 400 cold cranking amps (cca) is generally recommended for starting in all conditions. A smaller capacity battery is often suffi cient if an application is started only in warmer temperatures. Refer to following table for minimum capacities based on anticipated ambient temperatures. Actual cold cranking requirement depends on engine size, application, and starting temperatures. Cranking requirements increase as temperatures decrease and battery capacity shrinks. Refer to equipment's operating instructions for specifi c battery requirements.
Battery Size Recommendations
Temperature Battery Required
Above 32°F (0°C) 200 cca minimum
0°F to 32°F (-18°C to 0°C) 250 cca minimum
-5°F to 0°F (-21°C to -18°C) 300 cca minimum
-10°F (-23°C) or below 400 cca minimum
If battery charge is insuffi cient to turn over engine, recharge battery.
Battery Maintenance
Regular maintenance is necessary to prolong battery life.
Chalky, white deposits indicate very high combustion temperatures. This condition is usually accompanied by excessive gap erosion. Lean carburetor settings, an intake air leak, or incorrect spark timing are normal causes for high combustion temperatures.
Battery Test
To test battery, follow manufacturer's instructions.
58
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Page 59
Electrical System
BATTERY CHARGING SYSTEM
NOTE: Observe following guidelines to avoid damage to electrical system and components:
Make sure battery polarity is correct. A negative (-) ground system is used.
Disconnect recti er-regulator plug and/or wiring harness plug before doing any electric welding on equipment
powered by engine. Also, disconnect all other electrical accessories in common ground with engine.
Prevent stator (AC) leads from touching or shorting while engine is running. This could damage stator.
These engines are equipped with a 20 or 25 amp regulated charging system.
20/25 Amp Regulated Charging System
D
A
B
A Battery B Starter C Fuse D Recti er-Regulator
E Connector Block F
Stator
Stator is mounted on crankcase behind fl ywheel. Follow procedures in Disassembly and Reassembly if stator replacement is necessary.
Rectifi er-Regulator
NOTE: When installing rectifi er-regulator, take note of terminal markings and install plug(s) accordingly. NOTE: Disconnect all electrical connections attached to rectifi er-regulator. Testing may be performed with rectifi er-
regulator mounted or loose. Repeat applicable test procedure 2 or 3 times to determine condition of part.
Rectifi er-regulator is mounted on blower housing. To replace, disconnect plug(s), remove mounting screws, and ground wire or metal grounding strap.
Testing rectifi er-regulator may be performed as follows, using appropriate rectifi er-regulator tester. To test 20/25 amp rectifi er-regulators:
1. Connect tester ground lead (with spring clamp) to body of rectifi er-regulator.
2. Connect red lead from tester to middle terminal labeled B+.
3. Connect black leads from tester to both outer AC terminals on rectifi er-regulator.
4. Plug tester into proper AC outlet/power for tester being used. Turn on power switch. POWER light should be illuminated and one of four status lights may be lit as well. This does not represent condition of part.
5. Press TEST button until a click is heard and then release. Momentarily one of four status lights will illuminate indicating partial condition of part.
Flywheel Stator
Assembly
C
F
E
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Page 60
Electrical System
Condition Conclusion
20/25 amp
OK (green) light comes on and stays steady. Disconnect tester black lead attached to 1 AC terminal
and reconnect it to other AC terminal. Repeat test. If OK (green) light comes on again, part is good and may be used.
NOTE: A fl ashing LOW light can also occur as a result of
an inadequate ground lead connection. Make certain connection location is clean and clamp is secure.
Other lights come on.
Troubleshooting Guide
20/25 Amp Battery Charging System
NOTE: Always zero ohmmeter on each scale before
testing to ensure accurate readings. Voltage tests should be made with engine running at 3600 RPM - no load. Battery must be good and fully charged.
When problems occur in keeping battery charged or battery charges at too high a rate, problem can usually be found somewhere in charging system or with battery.
To test charging system for no charge to battery:
1. Insert an ammeter in B+ lead from rectifi er-regulator. With engine running at 3600 RPM and B+ (at terminal on rectifi er-regulator) to ground using a DC voltmeter.
If voltage is 13.8 volts or more, place a minimum
load of 5 amps (turn on lights if 60 watts or more, or place a 2.5 ohm, 100 watt resistor across battery terminals) on battery to reduce voltage. Observe ammeter.
Rectifi er-regulator is faulty and should not be used.
Condition Conclusion
Resistance is 0.064/0.2 ohms.
Resistance is 0 ohms. Stator is shorted; replace. Resistance is infi nity
ohms.
4. With engine stopped, measure resistance from each stator lead to ground using an ohmmeter.
Condition Conclusion
Resistance is infi nity ohms (no continuity).
Resistance (or continuity) measured.
To test charging system for battery continuously charging at high rate:
1. With engine running at 3600 RPM, measure voltage from B+ lead to ground using a DC voltmeter.
Stator is OK.
Stator is open; replace.
Stator is OK (not shorted to ground).
Stator leads are shorted to ground; replace.
Condition Conclusion
Charge rate increases when load is applied.
Charge rate does not increase when load is applied.
2. Remove connector from rectifi er-regulator. With engine running at 3600 RPM, measure AC voltage across stator leads using an AC voltmeter.
Condition Conclusion
Voltage is 28 volts or more.
Voltage is less than 28 volts.
3. With engine stopped, measure resistance across stator leads using an ohmmeter.
Charging system is OK and battery was fully charged.
Test stator and rectifi er- regulator (steps 2 and 3).
Stator is OK. Rectifi er- regulator is faulty; replace.
Stator is faulty; replace. Test stator further using an ohmmeter (steps 3 and 4).
Condition Conclusion
Voltage is 14.7 volts or less.
Voltage is more than 14.7 volts.
Charging system is OK. Battery is unable to hold charge; service or replace.
Faulty rectifi er-regulator; replace.
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Page 61
FUSES
This engine has 3 blade type automotive fuses. Replacement fuses must have same rating as blown fuse. Use fuse chart below to determine correct fuse.
Wire Color Fuse Rating
2 Purple Wires 30-amp Fuse
1 Red Wire w/ Black Stripe 1 Red Wire w/ White Stripe
2 Red Wires 10-amp Fuse
Fuse Replacement
1. Shut engine off and remove key.
2. Locate fuse holders.
3. Remove fuse cover and pull out fuse.
4. Inspect fuse for a solid fusible link or a broken
fusible link. Replace fuse if fusible link is broken. If you are not sure if fusible link is broken, replace fuse.
5. Insert fuse into fuse holder until it is seated properly.
Install fuse cover.
10-amp Fuse
Electrical System
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Page 62
Starter System
NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool down period between
starting attempts. Failure to follow these guidelines can burn out starter motor.
NOTE: If starter is engaged while fl ywheel is rotating, starter pinion and fl ywheel ring gear may clash and damage
starter.
NOTE: If starter does not crank engine, shut off starter immediately. Do not make further attempts to start engine
until condition is corrected. NOTE: Do not drop starter or strike starter frame. Doing so can damage starter. Engines in this series use solenoid shift starters.
Troubleshooting-Starting Diffi culties
Condition Possible Cause Conclusion
Starter does not energize. Battery Check specifi c gravity of battery. If low, recharge or replace
battery as necessary.
Wiring Clean corroded connections and tighten loose connections.
Replace wires in poor condition and with frayed or broken insulation.
Starter energizes but turns slowly.
Starter Switch
or Solenoid
Battery Check specifi c gravity of battery. If low, recharge or replace
Brushes Check for excessively dirty or worn brushes and commutator.
Transmission
or
Engine
By-pass switch or solenoid with a jumper wire. If starter cranks normally, replace faulty components. Remove and perform individual solenoid test procedure.
battery as necessary.
Clean using a coarse cloth (not emery cloth). Replace brushes if excessively or unevenly worn.
Make sure clutch or transmission is disengaged or placed in neutral. This is especially important on equipment with hydrostatic drive. Transmission must be exactly in neutral to prevent resistance which could keep engine from starting.
Check for seized engine components such as bearings, connecting rod, and piston.
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Page 63
Starter System
SOLENOID SHIFT STARTERS
When power is applied to starter electric solenoid moves drive pinion out onto drive shaft and into mesh with ywheel ring gear. When pinion reaches end of drive shaft it rotates fl ywheel and cranks engine.
When engine starts and start switch is released, starter solenoid is deactivated, drive lever moves back, and drive pinion moves out of mesh with ring gear into retracted position.
Solenoid Shift Starter Components
H
G
F
E
D
C
B
A
T
I
J
K
L
M
N
O
P
Q
R
S
Starter Disassembly
NOTE: Do not reuse old retainer. NOTE: Do not soak armature or use solvent when
cleaning. Wipe clean using a soft cloth, or use compressed air.
1. Remove hex nut and disconnect positive (+) brush lead/bracket from solenoid terminal.
2. Remove head screws securing solenoid to starter.
3. Unhook plunger pin from drive lever. Remove gasket from recess in housing.
4. Remove thru (larger) bolts.
5. Remove commutator end plate assembly, containing brush holder, brushes, springs, and locking caps. Remove thrust washer from inside commutator end.
6. Remove frame from armature and drive end cap.
7. Remove drive lever pivot bushing and backing plate (if equipped) from end cap.
8. Take out drive lever and pull armature out of drive end cap.
9. Remove thrust washer from armature shaft.
10. Push stop collar down to expose retaining ring.
11. Remove retainer from armature shaft. Save stop collar.
12. Remove drive pinion assembly from armature.
13. Clean parts as required.
Inspection
Drive Pinion
Check and inspect following areas:
Pinion teeth for abnormal wear or damage.
Surface between pinion and clutch mechanism for
nicks or irregularities which could cause seal damage.
Check drive clutch by holding clutch housing and
rotating pinion. Pinion should rotate in only 1 direction.
Brushes and Springs Detail
U
A Tube B Washer C Armature D Drive E Stop F Retaining Ring G Collar H Drive End Cap
I Screw J Plunger
K Spring L Lever
M Plate N Plug
O Solenoid P Frame and Field Q Brush Holder R Nut
Commutator End
S
U Bolt
Plate
T
Screw
A
A Wear Limit Length
Inspect both springs and brushes for wear, fatigue, or damage. Measure length of each brush. Minimum length for each brush is 7.6 mm (0.300 in.). Replace brushes if they are worn, undersize, or condition is questionable.
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Starter System
Armature Components and Details
A
B
A Commutator O.D. B Mica Insulation
C
E
D
C Insulation Check D Armature Coil E Continuity Check
1. Clean and inspect commutator (outer surface). Mica insulation must be lower than commutator bars (undercut) to ensure proper operation of commutator.
2. Use an ohmmeter set to Rx1 scale. Touch probes between 2 different segments of commutator, and check for continuity. Test all segments. Continuity must exist between all or armature is bad.
3. Check for continuity between armature coil segments and commutator segments. There should be no continuity. If continuity exists between any 2 armature is bad.
4. Check armature windings/insulation for shorting.
Shift Fork
Check that shift fork is complete, and pivot and contact areas are not excessively worn, cracked, or broken.
Brush Replacement
4 brushes and springs are serviced as a set. Use a new Kohler brush and spring kit if replacement is necessary.
1. Perform steps 1-5 in Starter Disassembly.
2. Remove screws securing brush holder assembly to
end cap (plate). Note orientation for reassembly later. Discard old brush holder assembly.
3. Clean component parts as required.
New brushes and springs come preassembled in a
brush holder with a protective sleeve that will also serve as an installation tool.
4. Perform steps 10-13 in Starter Reassembly
sequence. If starter has been disassembled, installation must be done after armature, drive lever, and frame are installed.
Starter Reassembly
NOTE: Always use a new retainer. Do not reuse old
retainers that have been removed.
NOTE: Correctly installed, center pivot section of drive
lever will be fl ush or below machined surface of housing.
1. Apply drive lubricant to armature shaft splines. Install drive pinion onto armature shaft.
2. Install and assemble stop collar/retainer assembly.
a. Install stop collar down onto armature shaft with
counter bore (recess) up.
b. Install a new retainer in larger (rear) groove of
armature shaft. Squeeze with a pliers to compress it in groove.
c. Slide stop collar up and lock it into place, so
recess surrounds retainer in groove. If necessary, rotate pinion outward on armature splines against retainer to help seat collar around retainer.
3. Install offset thrust (stop) washer so smaller offset of washer faces retainer/collar.
4. Apply a small amount of oil to bearing in drive end cap, and install armature with drive pinion.
5. Lubricate fork end and center pivot of drive lever with drive lubricant. Position fork end into space between captured washer and rear of pinion.
6. Slide armature into drive end cap and at same time seat drive lever into housing.
7. Install rubber grommet into matching recess of drive end cap. Molded recesses in grommet should be out, matching and aligned with those in end cap.
8. Install frame, with small notch forward, onto armature and drive end cap. Align notch with corresponding section in rubber grommet. Install drain tube in rear cutout, if it was removed previously.
9. Install fl at thrust washer onto commutator end of armature shaft.
10. Starter reassembly when replacing brushes/brush holder assembly:
a. Hold starter assembly vertically on end housing,
and carefully position assembled brush holder assembly, with supplied protective tube, against end of commutator/armature. Mounting screw holes in metal clips must be up/out. Slide brush holder assembly down into place around commutator, and install positive (+) brush lead grommet in cutout of frame. Protective tube may be saved and used for future servicing.
Starter reassembly when not replacing brushes/
brush holder assembly:
a. Carefully unhook retaining caps from brush
assemblies. Do not lose springs.
b. Position brushes back in their slots so they are
ush with I.D. of brush holder assembly. Insert brush installation tool (with extension), or use tube described above from a prior brush installation, through brush holder assembly, so holes in metal mounting clips are up/out.
64 62 690 05 Rev. --KohlerEngines.com
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Starter System
c. Install brush springs and snap on retainer caps. d. Hold starter assembly vertically on end housing, and carefully place tool (with extension) and assembled
original brush holder assembly onto end of armature shaft. Slide brush holder assembly down into place around commutator, install positive (+) brush lead grommet in cutout of frame.
11. Install end cap onto armature and frame, aligning thin raised rib in end cap with corresponding slot in grommet of positive (+) brush lead.
12. Install thru bolts and brush holder mounting screws. Torque bolts to 5.6-9.0 N·m (49-79 in. lb.) and brush holder mounting screws to 2.5-3.3 N·m (22-29 in. lb.).
13. Hook plunger behind upper end of drive lever and install spring into solenoid. Insert mounting screws through holes in drive end cap. Use these to hold solenoid gasket in position, then mount solenoid. Torque screws to
4.0-6.0 N·m (35-53 in. lb.).
14. Connect positive (+) brush lead/bracket to solenoid and secure with nut. Torque nut to 8-11 N·m (71-97 in. lb.). Do not overtighten.
Solenoid Tests
NOTE: DO NOT leave 12 volt test leads connected to solenoid for any time over what is necessary for performing
each of individual tests. Internal damage to solenoid may occur.
Disconnect all leads from solenoid including positive brush lead attached to lower stud terminal. Remove mounting hardware and separate solenoid from starter for testing.
To test solenoid pull-in coil/plunger: Actuation
1. Use a 12 volt power supply and 2 test leads.
2. Connect 1 lead to fl at spade S/start terminal on solenoid. Momentarily connect other lead to lower large post terminal.
When connection is made solenoid should energize
(audible click) and plunger retract. Repeat test several times.
Continuity
1. Use an ohmmeter set to audible or Rx2K scale, and connect 2 ohmmeter leads to 2 large post terminals.
2. Perform solenoid pull-in coil/plunger actuation test and check for continuity. Ohmmeter should indicate continuity. Repeat test several times.
To test solenoid hold-in coil: Function
1. Connect a 12 volt test lead to fl at spade S/start terminal on solenoid and other lead to body or mounting surface of solenoid.
2. Manually push plunger IN and check if coil holds plunger retracted. Do not allow test leads to remain connected to solenoid for a prolonged period of time.
Continuity
1. Use an ohmmeter set to audible or Rx2K scale, and connect 2 ohmmeter leads to 2 large post terminals.
2. Perform preceding solenoid hold-in coil function test and check for continuity. Meter should indicate continuity. Repeat test several times.
Condition Conclusion
Solenoid fails to activate. Replace solenoid. No continuity is indicated. Plunger fails to stay retracted.
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Disassembly/Inspection and Service
WARNING
Accidental Starts can cause severe injury or death.
Disconnect and ground spark plug lead(s) before servicing.
External Engine Components
S
R
M
N
L
K
O
H
D
Before working on engine or equipment, disable engine as follows: 1) Disconnect spark plug lead(s). 2) Disconnect negative (–) battery cable from battery.
S
Q
P
A
I
B
J
A Dipstick B Oil Drain Plug C Oil Fill Tube D Valley Baf e
E Spark Plug Lead F Barrel Baf e G Starter Assembly H Ignition Coil
Fuel Pump Module
I
M Electrical Connector N Evap Line O
Q Oil Filter R
Baffl e
F
B
E
F
G
J Fuel Filter K Fuel Pump Module L Fuel Pump
High Pressure Fuel
Line Connector
Blower Housing with
Fixed Guard
S Cylinder Shroud
C
P Oil Cooler
D
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Disassembly/Inspection and Service
Clean all parts thoroughly as engine is disassembled. Only clean parts can be accurately inspected and gauged for wear or damage. There are many commercially available cleaners that will quickly remove grease, oil and grime from engine parts. When such a cleaner is used, follow manufacturer’s instructions and safety precautions carefully.
Make sure all traces of cleaner are removed before engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down lubricating properties of engine oil.
NOTE: This disassembly sequence removes some
components in subassemblies to enable technician to perform internal engine servicing. Do not disconnect every EFI and electronic governor component.
Disconnect Spark Plug Leads
NOTE: Pull on boot only, to prevent damage to spark
plug lead.
1. Disconnect leads from spark plugs.
2. Shut off fuel supply.
Drain Oil from Crankcase and Remove Oil Filter
1. Clean oil fi lter and housing area. Remove and discard oil fi lter.
2. Remove dipstick and 1 oil drain plug.
3. Allow ample time for oil to drain from crankcase.
Remove Muffl er
Remove exhaust system and attaching hardware from engine. On engines equipped with a port liner, remove it now.
Remove Fuel Pump Module/Fuel Pump Assembly
WARNING
Explosive Fuel can cause fi res and severe burns.
Do not fi ll fuel tank while engine is hot or running.
Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.
1. Remove evap line & clips from fuel line clips and separate from fuel pump module.
2. Lift grey locking tab and squeeze to disconnect electrical connector from fuel pump module.
3. Wrap a shop towel completely around high pressure fuel line connector.
4. Press release button and slowly pull connector away from fuel pump module, allowing shop towel to absorb any residual fuel in high pressure fuel line. Any spilled fuel must be wiped up immediately.
5. Remove pulse line from crankcase fi tting.
6. Remove 3 screws securing fuel pump module baffl e to crankcase. Remove fuel pump module, baffl e, and fuel pump keeping all fuel lines connected.
Separate parts only if additional service is required.
Refer to page 82.
Do not cut any Oetiker clamps unless fuel lines and/
or fuel fi lter are being replaced.
Remove Cylinder Shrouds and Blower Housing
1. Remove top mounting screw and loosen shoulder screws on each side. Lift off cylinder shrouds.
2. Remove mounting screws and separate blower housing from backing shroud assembly. One screw also secures oil fi ll/dipstick tube. Fixed guard (if equipped) may be removed with blower housing.
If engine has pulse/lift pump mounted to blower
housing, remove two mounting screws.
3. Remove lower mounting screw and pull oil fi ll tube out of crankcase.
Remove Electric Starter Motor
1. Disconnect leads from starter.
2. Remove screws and starter.
Remove #1 Barrel and Valley Baffl es
1. Remove mounting screws from #1 barrel baffl e. Disconnect wiring harness from coil (#1 starter side). Let barrel baffl e hang (with coil installed).
2. Carefully remove clip securing wires to #1 valley baffl e. Remove 3 screws, then valley baffl e.
Remove Governor Springs, Linkage, and Lever (Mechanical Governor Only)
1. Unhook idle and governor springs from control bracket and governor lever. Note color, location, and position of each.
2. Disconnect throttle linkage and linkage spring from governor lever.
3. Loosen nut and remove governor lever from cross shaft.
Remove Oil Cooler
NOTE: New clamps are recommended any time
disassembly is performed, or if clamps have been loosened (expanded) several times.
1. Remove oil cooler mounting screws. Do not lose any washers (if used).
2. Note orientation of clamps before disassembling for proper clearance during reassembly. Loosen clamps and disconnect hoses from oil cooler. Cap hoses as required to prevent dirt infi ltration.
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Disassembly/Inspection and Service
Remove #2 Barrel and Valley Baffl es
1. Disconnect wiring harness lead from coil (#2 oil cooler side).
3. Remove screws and #2 side valley baffl e.
4. If necessary, carefully depress clip & remove coil from barrel baffl e.
2. Carefully depress back of high pressure fuel line mounting clip and separate from #2 barrel baffl e. Remove 5 screws (2 internal, 3 external), then remove barrel baffl e (with coil installed).
Flywheel/Backing Shroud/Intake and Throttle Body/Air Cleaner Assembly Components
G
A
B
C
D
E
F
H
K
L
I
J
M
N
O
P
A Special Washer B Debris Screen C Stiffener D Flywheel Screw
E Washer F
I Stator J
Flywheel/Fan/Hex
Stud Assembly
Rectifi er-Regulator
Connector
M Breather Hose N Oil Sentry
TM
Backing Shroud/
G
K
O
Oil Temperature
Intake Manifold/
Air Cleaner
MAP Sensor
Connector
Sensor
H Speed Sensor
L Ground Lead
P Reducer Bushing
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Disassembly/Inspection and Service
Remove Speed Sensor
1. Remove two bracket mounting screws and speed
sensor from backing shroud. Keep leads in place and let bracket and speed sensor lay on backing shroud.
2. Unplug connector from rectifi er-regulator. Remove
wiring harness ground lead from rectifi er-regulator mounting screw (outside edge). Rectifi er-regulator does not need to be removed from backing shroud.
3. Remove lead from oil temperature sensor (in oil
pan). Remove switch from oil pan only if replacing.
4. Remove screw securing harness bracket and ground
lead to #1 cylinder boss.
5. Remove other end of ground lead from #1 cylinder
boss screw. Be sure to keep washer.
Remove Debris Screen
Remove screws and special washers securing debris screen to studs in fl ywheel; then remove stiffener. Hex studs and cooling fan can stay attached to fl ywheel.
Remove Flywheel/Fan/Hex Stud Assembly
NOTE: Always use a fl ywheel strap wrench or holding
tool to hold fl ywheel when loosening or tightening fl ywheel screw. Do not use any type of bar or wedge to hold fl ywheel. Use of such tools could cause fl ywheel to become cracked or damaged.
NOTE: Always use a fl ywheel puller to remove fl ywheel
from crankshaft. Do not strike crankshaft or ywheel, as these parts could become cracked or damaged.
1. Use a fl ywheel strap wrench or holding tool to hold
ywheel and loosen screw securing fl ywheel to crankshaft.
2. Remove screw and washer.
3. Use a puller to remove fl ywheel from crankshaft.
4. Remove woodruff key from crankshaft.
Inspection
Inspect fl ywheel for cracks and fl ywheel keyway for damage. Replace fl ywheel if it is cracked. Replace ywheel, crankshaft, and key if fl ywheel key is sheared or keyway is damaged.
Inspect ring gear for cracks or damage. Kohler does not provide ring gear as a serviceable part. Replace fl ywheel if ring gear is damaged.
Remove Backing Shroud Assembly
1. Remove screws securing stator to backing shroud.
Keep leads in place and let stator lay on backing shroud.
2. Carefully slide lock tab outward. Press down on lock
tab to release, then separate connectors.
3. Remove screws securing backing shroud to
crankcase. Set backing shroud/harness assembly to #1 starter side.
Remove Intake and Throttle Body/Air Cleaner Assembly
1. Disconnect lead from Oil Sentry wire, red terminal). Remove switch from oil pan only
switch. (Green
if replacing.
2. Disconnect oil temperature sensor connector. Unless sensor is damaged or malfunctioning, disassembly from crankcase is unnecessary.
3. Remove breather hose from breather cover. (Other end is connected to throttle body assembly.)
4. Loosen but do not remove throttle body/intake manifold. Support manifold and remove this assembly when fi nal intake manifold bolt is taken out, along with backing plate assembly.
Assembly includes air cleaner, hose, elbow, throttle
body, intake manifold, fuel rail assembly, injectors, MAP sensor, intake air temperature sensor, ECU, and brackets. If equipped with electronic governor it also includes GCU, DLA, and electronic governor wiring harness.
Separate parts only if additional service is required.
Refer to pages 80-82.
Remove Oil Filter Housing
Oil Filter Housing Components
A
B
C
D
E
F
G
H
I
A Oil Filter Nipple B Cup
C Valve Spring D Cup Spring
E Oil Filter Valve F Screw
G Oil Filter Housing H Pin
I O-Ring
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Disassembly/Inspection and Service
NOTE: Further disassembly of oil fi lter housing
assembly is not required unless being serviced individually. Follow substeps a, b, and c.
1. Remove screw securing oil fi lter housing and individual O-rings to crankcase. Carefully separate parts.
Cylinder Head Components
C
B
G
H
D
F
Perform following only if oil fi lter housing assembly
requires individual servicing. a. Remove nipple from cup and oil fi lter housing. b. Remove oil fi lter cup and spring from housing. c. Remove rubber valve and spring from cup.
Style B Style A
M
L
N
V
W
Z
Y
U
E
I
J
K
A
A Gasket B Valve C Cylinder Head D Pipe Plug
E Guide Plate F Spacer G Washer H Spark Plug
I Valve Stem Seal J Valve Spring K Valve Spring Retainer L Hydraulic Lifter
M Valve Spring Keeper N Push Rod O Rocker Arm P Rocker Arm Pivots
Q Rocker Stud R Valve Cover Seal S Valve Cover T Grommet
U
Y Rocker Arm Screw Z
Remove Spark Plugs
Remove spark plug from each cylinder head.
Hydraulic Lifter
Style A (Ribbed)
V
Hydraulic Lifter
Style B (Smooth)
Non-adjustable Valve
Train (Non-AVT)
Q
O
P
X
W Adjusting Nut X
Remove Valve Covers
1. Remove screw and grommet securing each valve
cover.
2. Remove valve cover and seal from each cylinder
head. Note locations of individual valve covers if
they are different.
R
S
Adjustable Valve
T
Train (AVT)
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Disassembly/Inspection and Service
Remove Cylinder Heads and Hydraulic Lifters
NOTE: Exhaust lifters are located on output shaft side of
engine while intake lifters are located on fan side of engine. Cylinder head number is embossed on outside of each cylinder head.
1. Non-adjustable Valve Train a. Remove rocker arm screws, rocker arm pivots
and rocker arms. Adjustable Valve Lash a. Loosen set screws and remove adjusting nuts on
rocker arm pivot studs. b. Remove rocker arm pivot and rocker arms.
2. Remove pipe plug from cylinder head to access
screw in center location.
3. Remove screws securing each cylinder head. Note
locations of washers and spacer.
4. Mark position of push rods as either intake or
exhaust and cylinder #1 or #2. Push rods should always be reinstalled in same positions.
5. Carefully remove push rods, cylinder head, and head
gasket.
6. Repeat procedure for other cylinder head.
7. Remove lifters from lifter bores. Use a hydraulic lifter
tool. Do not use a magnet to remove lifters. Mark lifters by location, as either intake or exhaust and cylinder #1 or #2. Hydraulic lifters should always be reinstalled in same position.
Inspection
Check base surface of hydraulic lifters for wear or damage. If lifters need to be replaced, apply a liberal coating of Kohler lubricant to base of each new lifter before it is installed.
Bleeding Lifters Style A (Ribbed)
To prevent a possible bent push rod or broken rocker arm, it is important to bleed any excess oil out of lifters before they are installed.
1. Cut a 50-75 mm (2-3 in.) piece from end of an old push rod and chuck it in a drill press.
2. Lay a rag or shop towel on table of drill press and place lifter, open end up, on towel.
3. Lower chucked push rod until it contacts plunger in lifter. Slowly pump plunger 2 or 3 times to force oil out of feed hole in side of lifter.
Bleeding Lifters Style B (Smooth)
To prevent a possible bent push rod or broken rocker arm, it is important to bleed any excess oil out of lifters before they are installed.
1. Lay a rag or shop towel on table of drill press. Place an 8 mm (5/16 in.) socket on towel with well end up, then place open end of lifter on socket. Ensure socket does not contact lifter ball surface.
2. Place some material, such as wood, plastic, or aluminum on top of lifter to protect lifter fi nish.
3. Lower drill press chuck until it contacts material on lifter. Slowly pump lifter 2 or 3 times to force oil out of feed hole in side of lifter.
Disassemble Cylinder Heads
NOTE: These engines use valve stem seals on intake and exhaust valves. Use a new seal whenever valves are
1. Non-adjustable Valve Train Remove screws, rocker arm pivots, and rocker arms from cylinder head. Adjustable Valve Train Remove adjusters, rocker arm pivots, and rocker arms from cylinder head. Remove pivot studs and guide plate as
2. Compress valve springs using a valve spring compressor.
3. Once valve spring is compressed, remove following items:
4. Repeat above procedure for other cylinder head. Do not interchange parts from 1 cylinder head to another.
removed, or if seal is deteriorated in any way. Never reuse an old seal.
required.
Valve spring keepers.
Valve spring retainers.
Valve springs.
Valve spring caps.
Intake and exhaust valves (mark position).
Valve stem seals.
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Disassembly/Inspection and Service
Inspection and Service Valve Details
EXHAUST VALVE INTAKE VALVE
F F
E E
C
G G
D
INT
H H
EXH
D
Dimension Intake Exhaust
A Seat Angle 89° 89°
B Seat Taper 30° 30°
C Guide Depth 8.5 mm (0.334 in.) 8.5 mm (0.334 in.)
D Guide I.D. 7.038/7.058 mm (0.2771/0.2779 in.) 7.038/7.058 mm (0.2771/0.2779 in.)
E Valve Head Diameter 38.625/38.685 mm (1.5206/1.5230 in.) 31.625/31.825 mm (1.2450/1.2549 in.)
F Valve Face Angle 45° 45°
G Valve Margin (Min.) 1.0 mm (0.0393 in.) 1.0 mm (0.0393 in.)
H Valve Stem Diameter 6.982/7.000 mm (0.2749/0.2756 in.) 6.970/6.988 mm (0.2744/0.2751 in.)
A
B
After cleaning, check fl atness of cylinder head and corresponding top surface of crankcase using a surface plate or piece of glass and feeler gauge. Maximum allowable out of fl atness is 0.076 mm (0.003 in.).
Carefully inspect valve mechanism parts. Inspect valve springs and related hardware for excessive wear or distortion. Check valves and valve seat area or inserts for evidence of deep pitting, cracks, or distortion. Check clearance of valve stems in guides.
Hard starting or loss of power accompanied by high fuel consumption may be symptoms of faulty valves. Although these symptoms could also be attributed to worn rings, remove and check valves fi rst. After removal, clean valve heads, faces, and stems with a power wire brush.
Then, carefully inspect each valve for defects such as a warped head, excessive corrosion, or a worn stem end. Replace valves found to be in bad condition.
Valve Guides
If a valve guide is worn beyond specifi cations, it will not guide valve in a straight line. This may result in burnt valve faces or seats, loss of compression, and excessive oil consumption.
To check valve guide-to-valve stem clearance, thoroughly clean valve guide and, using a split-ball gauge, measure inside diameter of guide. Then, using an outside micrometer, measure diameter of valve stem at several points on stem where it moves in valve guide. Use largest stem diameter to calculate clearance by subtracting stem diameter from guide diameter. If intake clearance exceeds 0.038/0.076 mm (0.0015/0.0030 in.) or exhaust clearance exceeds 0.050/0.088 mm (0.0020/0.0035 in.), determine if valve stem or guide is responsible for excessive clearance.
Maximum (I.D.) wear on intake valve guide is 7.135 mm (0.2809 in.) and 7.159 mm (0.2819 in.) for exhaust guide. Guides are not removable but can be reamed
0.25 mm (0.010 in.) oversize. Valves with 0.25 mm oversize stems must then be used.
If guides are within limits but valve stems are worn beyond limits, install new valves.
Valve Seat Inserts
Hardened steel alloy intake and exhaust valve seat inserts are press fi tted into cylinder head. Inserts are not replaceable but can be reconditioned if not too badly pitted or distorted. If cracked or badly warped, cylinder head should be replaced.
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Disassembly/Inspection and Service
Recondition valve seat inserts following instructions provided with valve seat cutter being used. Final cut should be made with an 89° cutter as specifi ed for valve seat angle. Cutting proper 45° valve face angle as specifi ed, and proper valve seat angle (44.5°, half of full 89° angle), will achieve desired 0.5° (1.0° full cut) interference angle where maximum pressure occurs on outside diameters of valve face and seat.
Lapping Valves
Reground or new valves must be lapped in, to provide proper fi t. Use a hand valve grinder with a suction cup for fi nal lapping. Lightly coat valve face with a fi ne grade
Breather/Oil Pan Components
of grinding compound, then rotate valve on its seat with grinder. Continue grinding until a smooth surface is obtained on seat and on valve face. Thoroughly clean cylinder head in soap and hot water to remove all traces of grinding compound. After drying cylinder head, apply a light coating of SAE 10 oil to prevent rusting.
Valve Stem Seals
These engines use valve stem seals on intake and exhaust valves. Always use new seals when valves are removed from cylinder head. Seals should also be replaced if deteriorated or damaged in any way. Never reuse an old seal.
M
L
K
D
F
I
H
A
J
E
C
F
G
B
A Oil Pan B Gerotor Gears C Oil Pump O-Ring D Oil Pump Housing
E Pickup Tube F Inlet Seal G Pickup Screen H Drain Plug
N
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Disassembly/Inspection and Service
1,4
3
2
Crankshaft Bearing
I
M Breather Assembly N Oil Seal
(PTO)
J Oil Pan Gasket K Breather Filter L Breather Gasket
Remove Breather Assembly
1. Carefully remove harness clip from #1 valley baffl e (if not already removed).
2. Remove fasteners securing breather assembly and gasket to crankcase.
3. Carefully break gasket seal and remove breather and fi lter. Do not pry on sealing surfaces as it could cause damage resulting in leaks. Note assembly and orientation of parts.
Remove Oil Pan Assembly
1. Remove screws securing oil pan to crankcase.
2. Locate protruding tabs on oil pan. Carefully tap to break gasket seal. Do not pry on sealing surfaces as this could cause leaks. Separate oil pan from crankcase. Remove old gasket.
Inspection
Inspect oil seal in oil pan and remove it if it is worn or damaged.
Inspect crankshaft bearing surface for wear or damage. Replace bearing or oil pan assembly if required.
Oil Pump Assembly
Disassembly
1. Remove screws securing oil pump housing including screw for pickup screen.
2. Remove oil pump housing and pickup screen from oil pan.
3. Remove oil pump gerotor gears from oil pan recess.
4. Remove oil pickup by pulling it free from oil pump body.
5. Relief valve is a one-piece style, staked to oil pump housing; removal should not be attempted, nor is internal servicing possible. If a problem with relief valve is encountered, oil pump should be replaced.
Inspection
Inspect oil pump housing, gerotor gears, and oil pan recess for nicks, burrs, wear, or any visible damage. Inspect inlet seal for pickup tube in housing. If any parts are worn or damaged, replace seal, oil pump or oil pan as required.
Reassembly
Torque Sequence
3
1,4
2
1. Make sure recess in oil pan for oil pump gerotor gears is clean.
2. Lubricate oil pump gerotor gears with grease (Lubriplate® 100 or equivalent), and install into recess.
3. Lightly lubricate with oil and install inlet seal into oil pump housing until it is fully seated.
4. Install O-ring in groove of oil pump housing. Use a small quantity of grease to hold it in place.
5. Lightly lubricate I.D. of inlet seal with oil and carefully insert end of pickup tube through seal into oil pump housing.
6. Install oil pump housing with pickup tube, over oil pump boss and gears. Align all 3 screw locations.
7. Check alignment of parts and torque oil pump housing screws 9.9 N·m (88 in. lb.) using sequence below:
a. Install fastener into screw location 1 and lightly
tighten to position pump.
b. Install fastener into screw location 2 and fully
torque to recommended value.
c. Install fastener into screw location 3 and fully
torque to recommended value.
d. Finish torquing fastener in screw location 1 to
recommended value.
8. Install and torque pickup screen mounting screw to
11.3 N·m (100 in. lb.) into new hole or 7.7 N·m (68 in. lb.) into used hole.
74 62 690 05 Rev. --KohlerEngines.com
Page 75
Disassembly/Inspection and Service
Crankcase Components
M
O
L
K
J
Remove Camshaft
Remove camshaft and shim (if used).
Inspection
A
B
I
N
D
C
E
G
H
F
Check lobes of camshaft for wear or damage. Inspect cam gear for badly worn, chipped, or missing teeth. Replacement of camshaft will be necessary if any of these conditions exist.
Remove Connecting Rods with Pistons and Rings
NOTE: If a carbon ridge is present at top of either
cylinder bore, use a ridge reamer tool to remove ridge before attempting to remove piston.
NOTE: Cylinders are numbered on crankcase. Use
numbers to mark each end cap, connecting rod and piston for reassembly. Do not mix end caps and connecting rods.
1. Remove screws securing closest connecting rod end
cap. Remove end cap.
2. Carefully remove connecting rod and piston
assembly from cylinder bore.
3. Repeat above procedures for other connecting rod
and piston assembly.
Connecting Rods
Offset, stepped-cap connecting rods are used in these engines.
Inspection and Service
Check bearing area (big end) for excessive wear, score marks, running and side clearances. Replace rod and cap if scored or excessively worn.
Service replacement connecting rods are available in STD crankpin size and 0.25 mm (0.010 in.) undersize. Always refer to appropriate parts information to ensure that correct replacements are used.
A Camshaft B Locking Tab*
C Regulating Pin* D Governor Gear*
E Cross Shaft* F Lifter Feed Cover
G Lifter Feed Cover H Governor Yoke*
I Crankshaft J Connecting Rod
K Connecting Rod L Piston Pin
M Piston Pin Retainer N Piston
O Piston Ring Set P Oil Seal
*Mechanical Governor only.
P
Gasket
End Cap
7562 690 05 Rev. -- KohlerEngines.com
Page 76
Disassembly/Inspection and Service
Piston and Rings
Inspection Piston and Rings Components and Details
A
B
C
D
E
F
G
I
H
A Piston Ring B End Gap
C Identi cation Mark D Piston
Top Compression
E
G Rails H Expander
I
Scuffi ng and scoring of pistons and cylinder walls occurs when internal engine temperatures approach welding point of piston. Temperatures high enough to do this are created by friction, which is usually attributed to improper lubrication and/or overheating of engine.
Normally, very little wear takes place in piston boss­piston pin area. If original piston and connecting rod can be reused after new rings are installed, original pin can also be reused but new piston pin retainers are required. Piston pin is included as part of piston assembly – if pin boss in piston or pin are worn or damaged, a new piston assembly is required.
Ring failure is usually indicated by excessive oil consumption and blue exhaust smoke. When rings fail, oil is allowed to enter combustion chamber where it is burned along with fuel. High oil consumption can also occur when piston ring end gap is incorrect because ring cannot properly conform to cylinder wall under this condition. Oil control is also lost when ring gaps are not staggered during installation.
Ring
Oil Control Ring
(3 Piece)
F
Center
Compression Ring
When cylinder temperatures get too high, lacquer and varnish collect on pistons causing rings to stick, which results in rapid wear. A worn ring usually takes on a shiny or bright appearance.
Scratches on rings and pistons are caused by abrasive material such as carbon, dirt, or pieces of hard metal.
Detonation damage occurs when a portion of fuel charge ignites spontaneously from heat and pressure shortly after ignition. This creates 2 fl ame fronts which meet and explode to create extreme hammering pressures on a specifi c area of piston. Detonation generally occurs from using low octane fuels.
Preignition or ignition of fuel charge before timed spark can cause damage similar to detonation. Preignition damage is often more severe than detonation damage. Preignition is caused by a hot spot in combustion chamber from sources such as glowing carbon deposits, blocked cooling fi ns, an improperly seated valve, or wrong spark plug(s).
Replacement pistons are available in STD bore size, and in 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize. Replacement pistons include new piston ring sets and new piston pins.
Replacement ring sets are also available separately for STD, 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize pistons. Always use new piston rings when installing pistons. Never reuse old rings.
Some important points to remember when servicing piston rings:
1. Cylinder bore must be deglazed before service ring sets are used.
2. If cylinder bore does not need reboring and if old piston is within wear limits and free of score or scuff marks, old piston may be reused.
3. Remove old rings and clean up grooves. Never reuse old rings.
4. Before installing new rings on piston, place top 2 rings, each in turn, in its running area in cylinder bore and check end gap. Top and center compression ring end gap clearance is 0.30/0.55 mm (0.011/0.021 in.) with maximum wear limit of
0.94 mm (0.037 in.).
5. After installing new compression (top and middle) rings on piston, make sure ring-to-groove side clearance is 0.04/0.08 mm (0.0015/0.0031 in.). If side clearance is greater than specifi ed, a new piston must be used.
Install New Piston Rings
NOTE: Rings must be installed correctly. Ring
installation instructions are usually included with new ring sets. Follow instructions carefully. Use a piston ring expander to install rings. Install bottom (oil control) ring fi rst and top compression ring last.
To install new piston rings, proceed as follows:
1. Oil control ring (bottom groove): Install expander and then rails. Make sure ends of expander are not overlapped.
76 62 690 05 Rev. --KohlerEngines.com
Page 77
Disassembly/Inspection and Service
2. Middle compression ring (center groove): Install center ring using a piston ring installation tool. Make sure identifi cation mark is up or colored dye stripe (if contained), is to left of end gap.
3. Top compression ring (top groove): Install top ring using a piston ring expander. Make sure identifi cation mark is up or colored dye stripe (if contained), is to left of end gap.
Remove Crankshaft
NOTE: If crankpin is reground, visually check to ensure
that fi llet blends smoothly with crankpin surface.
Carefully pull crankshaft from crankcase. Note thrust washers and shims if used.
Inspection and Service Crankshaft Components and Details
A
B
C
D
A Self-Tapping Screw B Flat Washer
C Plug D Crankshaft
F
G
E
H
Fillet Must Blend Smoothly with Bearing Journal
E
F High Point from Fillet Intersections
G 45° Minimum
H This Fillet Area Must Be Completely Smooth
Surface
Inspect gear teeth of crankshaft. If teeth are badly worn, chipped, or some are missing, replacement of crankshaft will be necessary.
Inspect crankshaft bearing surfaces for scoring, grooving, etc. A replaceable bearing is used in crankshaft bore of oil pan. Do not replace bearing unless it shows signs of damage, or is out of running clearance
0.040/0.167 mm (0.0015/0.0065 in.). If crankshaft turns easily, without noise, and there is no evidence of scoring, grooving, etc., on races or bearing surfaces, bearing can be reused.
Inspect crankshaft keyways. If they are worn or chipped, replacement of crankshaft will be necessary.
Inspect crankpin for score marks or metallic pickup. Slight score marks can be cleaned with crocus cloth soaked in oil. If wear limits, as stated in Clearance Specifi cations, are exceeded, it will be necessary to replace crankshaft or regrind crankpin to 0.25 mm (0.010 in.) undersize. If reground, a 0.25 mm (0.010 in.) undersize connecting rod (big end) must then be used to achieve proper running clearance. Measure crankpin for size, taper, and out-of-round.
Clearance Specifi cations-Connecting Rod Journal
O.D. - New 43.982/44.000 mm
(1.731/1.732 in.) O.D. - Max. Wear Limit 43.97 mm (1.731 in.) Max. Taper 0.018 mm (0.0007 in.) Max. Out-of-Round 0.025 mm (0.0010 in.) Width 53.00/53.09 mm
(2.0866/2.0901 in.)
Connecting rod journal can be ground 1 size under. When grinding a crankshaft, grinding stone deposits can get caught in oil passages, which could cause severe engine damage. Removing crankpin plug when crankshaft is ground provides easy access for removing any grinding deposits that may collect in oil passages.
Use following procedure to remove and replace plug.
Remove Crankshaft Plug
1. Drill a 3/16 in. hole through plug in crankshaft.
2. Thread a 3/4 in. or 1 in. long self-tapping screw with a fl at washer into drilled hole. Flat washer must be large enough to seat against shoulder of plug bore.
3. Tighten self-tapping screw until it draws plug out of crankshaft.
Install New Crankshaft Plug
Use 1 single cylinder camshaft pin, as a driver and tap plug into plug bore until it seats at bottom of bore. Make sure plug is tapped in evenly to prevent leakage.
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Page 78
Disassembly/Inspection and Service
Remove Governor Gear Assembly (Mechanical Governor Only)
Governor gear is held onto shaft by small molded tabs in gear. When gear is removed from shaft, these tabs are destroyed and gear must be replaced. Therefore, remove gear only if absolutely necessary. If governor cross shaft, yoke, or gear condition does not require removal, governor gear may be left in place. If removal is necessary, perform as follows:
1. Remove locking tab thrust washer and note orientation.
2. Using a screwdriver, carefully pry upward to unseat governor gear assembly from governor gear shaft. Remove regulating pin and governor gear assembly.
3. Inspect governor gear shaft for wear or damage. Remove shaft only if replacement is needed.
Inspection
Governor gear is located within crankcase. Inspect governor gear teeth. Replace gear if it is worn, chipped, or if any teeth are missing. Inspect governor weights. They should move freely in governor gear.
Remove Governor Yoke, Cross Shaft, and Seal (Mechanical Governor Only)
1. Remove mounting screws securing yoke to governor cross shaft.
2. Pull governor cross shaft out of crankcase and remove seal.
Crankcase
Inspection and Service
Check all gasket surfaces to make sure they are free of gasket fragments. Gasket surfaces must also be free of deep scratches or nicks.
Check cylinder bore for scoring. In severe cases, unburned fuel can cause scuffi ng and scoring of cylinder wall. It washes necessary lubricating oils off piston and cylinder wall. As raw fuel seeps down cylinder wall, piston rings make metal to metal contact with wall. Scoring of cylinder wall can also be caused by localized hot spots resulting from blocked cooling fi ns or from inadequate or contaminated lubrication.
If cylinder bore is badly scored, excessively worn, tapered, or out-of-round, resizing is necessary. Use an inside micrometer to determine amount of wear, then select nearest suitable oversize of either 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.). Resizing to these oversizes will allow usage of available oversize piston and ring assemblies. Initially, resize using a boring bar, then use following procedures for honing cylinder.
Honing Detail
A
Remove Lifter Feed Chamber Cover and Gaskets
Remove screws securing lifter feed chamber cover and gaskets. Carefully separate parts from crankcase.
Remove Flywheel End Oil Seal
Remove oil seal from crankcase using a seal puller.
A 23°-33° Crosshatch
NOTE: Kohler pistons are custom-machined to exacting
tolerances. When oversizing a cylinder, it should be machined exactly 0.25 mm (0.010 in.) or
0.50 mm (0.020 in.) over new diameter. corresponding oversize Kohler replacement piston will then fi t correctly.
While most commercially available cylinder hones can be used with either portable drills or drill presses, use of a low speed drill press is preferred as it facilitates more accurate alignment of bore in relation to crankshaft crossbore. Honing is best accomplished at a drill speed of about 250 RPM and 60 strokes per minute. After installing coarse stones in hone, proceed as follows:
78 62 690 05 Rev. --KohlerEngines.com
Page 79
Disassembly/Inspection and Service
1. Lower hone into bore and after centering, adjust so
stones are in contact with cylinder wall. Use of a commercial cutting-cooling agent is recommended.
2. With lower edge of each stone positioned even with
lowest edge of bore, start drill and honing process. Move hone up and down while resizing to prevent formation of cutting ridges. Check size frequently.
3. When bore is within 0.064 mm (0.0025 in.) of
desired size, remove coarse stones and replace them with burnishing stones. Continue with burnishing stones until bore is within 0.013 mm (0.0005 in.) of desired size and then use fi nish stones (220-280 grit) and polish bore to its fi nal size. A crosshatch should be observed if honing is done correctly. Crosshatch should intersect at approximately 23°-33° off horizontal. Too fl at an angle could cause rings to skip and wear excessively, and too steep an angle will result in high oil consumption.
4. After resizing, check bore for roundness, taper, and
size. Use an inside micrometer, telescoping gauge, or bore gauge to take measurements. These measurements should be taken at 3 locations in cylinder – at top, middle, and bottom. There are 2 measurements that should be taken (perpendicular to each other) at all 3 locations.
Clean Cylinder Bore After Honing
Proper cleaning of cylinder walls following boring and/ or honing is very critical to a successful overhaul. Machining grit left in cylinder bore can destroy an engine in less than 1 hour of operation after a rebuild.
Final cleaning operation should always be a thorough scrubbing with a brush and hot, soapy water. Use a strong detergent that is capable of breaking down machining oil while maintaining a good level of suds. If suds break down during cleaning, discard dirty water and start again with more hot water and detergent. Following scrubbing, rinse cylinder with very hot, clear water, dry it completely, and apply a light coating of engine oil to prevent rusting.
Measuring Piston-to-Bore Clearance Piston Detail
A
A 11 mm (0.4331 in.)
NOTE: Do not use a feeler gauge to measure piston-to-
bore clearance; it will yield inaccurate measurements. Always use a micrometer.
Before installing piston into cylinder bore, it is necessary that clearance be accurately checked. This step is often overlooked, and if piston thrust face-to-cylinder bore running clearance is not within 0.033/0.071 mm (0.0013/0.0028 in.), engine failure will usually result.
Use following procedure to accurately measure piston­to-bore clearance:
1. Use a micrometer and measure diameter of piston 11 mm (0.4331 in.) above bottom of piston skirt and perpendicular to piston pin.
2. Use an inside micrometer, telescoping gauge, or bore gauge and measure cylinder bore. Take measurement approximately 63.5 mm (2.5 in.) below top of bore and perpendicular to piston pin.
3. Piston-to-bore clearance is difference between bore diameter and piston diameter (step 2 minus step 1).
7962 690 05 Rev. -- KohlerEngines.com
Page 80
Disassembly/Inspection and Service
Electronic Governor Intake and Throttle Body Assembly Components
S
J
O
R
P
Q
A
A Elbow B Elbow O-ring C Throttle Body D Intake Manifold
E Fuel Rail Assembly F Breather Hose G Injector H MAP Sensor
I ECU J
Throttle Body Lever
M
Q GCU Module R DLA S
Adapter
N Linkage & Spring O GCU Bracket P DLA Bracket
N
B
C
Air Cleaner Bracket
K
M
Assembly
L
H
D
K
I
E
Air Temperature
Sensor
GCU Wiring Harness
Connector
G
F
L Lifting Bracket
Remove Throttle Body (Electronic Governor)
1. Disconnect TPS wire.
2. Loosen 2 screws securing lifting bracket and air cleaner bracket to intake manifold.
3. Remove nuts securing elbow and throttle body.
4. Remove 3 screws securing GCU bracket.
5. Disconnect link clip from outboard end of DLA; remove spring and linkage.
6. Carefully lift and move air cleaner brackets/ECU/ GCU up on front section of engine. Secure temporarily to access and replace throttle body.
7. Disconnect intake air temperature sensor from throttle body.
8. Disconnect breather tube from throttle body.
9. Disconnect throttle position sensor connector.
80 62 690 05 Rev. --KohlerEngines.com
10. Disconnect vent hose from bottom of throttle body.
11. Slide throttle body off studs.
12. Reverse procedure to reassemble, torque fasteners to proper specifi cations. Air cleaner bracket screws to 11.3 N·m (100 in. lb.); Air cleaner elbow to throttle body nuts to 7.9 N·m (70 in. lb.).
Remove GCU (Electronic Governor)
1. Remove screws securing GCU to GCU bracket.
2. Unplug wiring harness connector from GCU.
3. Reverse procedure to install. Torque screws to 2.1 N·m (19 in. lb.).
Page 81
Disassembly/Inspection and Service
Mechanical Governor Intake and Throttle Body Assembly Components
J
I
L
K
B
A
C
N
A Elbow B Elbow O-ring C Throttle Body D Intake Manifold
E Fuel Rail Assembly F Breather Hose G Injector H MAP Sensor
I ECU J
M Throttle Linkage N Linkage Spring
Remove Throttle Body (Mechanical Governor)
1. Disconnect TPS wire.
2. Loosen 2 screws securing air cleaner bracket and speed control bracket to intake manifold.
3. Remove nuts securing elbow and throttle body.
4. Unhook idle and governor springs from control bracket and governor lever. Note location and position of each.
5. Disconnect throttle linkage and linkage spring from governor lever. Note location and position of each.
6. Carefully lift and move air cleaner brackets/ECU up on front section of engine. Secure temporarily to access and replace throttle body.
M
Air Cleaner Bracket
Assembly
H
D
E
K
7. Disconnect intake air temperature sensor from
8. Disconnect breather tube from throttle body.
9. Disconnect throttle position sensor connector.
10. Disconnect vent hose from bottom of throttle body.
11. Slide throttle body off studs.
12. Reverse procedure to reassemble, torque fasteners
Air Temperature
Sensor
throttle body.
to proper specifi cations. Air cleaner bracket screws to 11.3 N·m (100 in. lb.); Air cleaner elbow to throttle body nuts to 7.9 N·m (70 in. lb.).
G
F
L
Speed Control
Bracket
8162 690 05 Rev. -- KohlerEngines.com
Page 82
Disassembly/Inspection and Service
Remove ECU
1. Remove screws securing ECU to bracket.
2. Disconnect black and grey electrical connectors from ECU.
3. Reverse procedure to install. Torque screws to 6.2 N·m (55 in. lb.).
Remove Fuel Injectors
1. Disconnect electrical connector.
2. Remove screw for each injector and pull injector out of intake manifold.
3. When removed, pull metal retaining clip connecting fuel injector to fuel injector cap. There may be some fuel left in line. Any spilled fuel must be cleaned up immediately.
4. Reverse procedure to install. Torque fuel injector cap screws to 7.3 N·m (65 in. lb.).
Remove Manifold Absolute Pressure (MAP) Sensor
1. With a screwdriver, slide locking tab on electrical connector.
2. Carefully slide lock tab outward. Press down on lock tab to release, then separate connectors.
3. Remove screw and pull MAP sensor out of intake manifold.
4. Reverse procedure to install. Torque screw to 7.3 N·m (65 in. lb.).
Remove Fuel Pump Module/Fuel Pump Assembly
WARNING
Explosive Fuel can cause fi res and severe burns.
Do not fi ll fuel tank while engine is hot or running.
Gasoline is extremely fl ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or fl ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.
Fuel Pump Module/Fuel Pump was removed as an assembly. An exploded view of that assembly with steps to disassemble it follow.
Fuel Pump Module/Pump Assembly Components
H
I
G
J
K
F
L
E
D
C
B
A Fuel Pump Module B
C Inlet Port D
E Evap Line F Electrical Connector
G Inlet Line H Fuel Pump
I Outlet Line J Pulse Line
K Fuel Filter L Crankcase Fitting
1. Remove screws securing fuel pump module to baffl e.
2. Using a side cutter or similar tool, cut Oetiker clamp to remove fuel line from fuel pump module inlet port.
3. Disconnect inlet, outlet, and pulse (vacuum) lines at fuel pump.
High Pressure Fuel
Fuel Pump Module
A
Line Connector
Baffl e
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Page 83
Reassembly
Crankcase Components
M
O
L
K
J
NOTE: Make sure engine is assembled using all
specifi ed torque values, torque sequences, and clearances. Failure to observe specifi cations could cause severe engine wear or damage.
A
B
I
N
D
C
E
G
H
F
Make sure all traces of any cleaner are removed before engine is assembled and placed into operation. Even small amounts of these cleaners can quickly break down lubricating properties of engine oil.
Check oil pan, crankcase, cylinder heads, and valve covers to be certain all old gasket material has been removed. Use gasket remover, lacquer thinner, or paint remover to remove any remaining traces. Clean surfaces with isopropyl alcohol, acetone, lacquer thinner, or electrical contact cleaner.
Install Flywheel End Oil Seal
1. Make sure seal bore of crankcase is clean and free
2. Apply a light coat of clean engine oil to outside
3. Install oil seal into crankcase using a seal driver.
Install Lifter Feed Chamber Gasket and Cover
1. Install lifter feed chamber gasket, followed by lifter
2. Install screws. Make sure all parts are properly
Always use new gaskets. Apply a small amount of oil to threads of critical fasteners before assembly, unless a sealant or Loctite® is specifi ed or preapplied.
of any nicks or burrs.
diameter of oil seal.
Make sure oil seal is installed straight and true in bore and tool bottoms against crankcase.
feed cover over lifter feed chamber.
aligned. Torque screws to 6.6 N·m (58 in. lb.).
A Camshaft B Locking Tab*
C Regulating Pin* D Governor Gear*
E Cross Shaft* F Lifter Feed Cover
G Lifter Feed Cover H Governor Yoke*
I Crankshaft J Connecting Rod
K Connecting Rod L Piston Pin
M Piston Pin Retainer N Piston
O Piston Ring Set P Oil Seal
*Mechanical Governor only.
P
Gasket
End Cap
8362 690 05 Rev. -- KohlerEngines.com
Page 84
Reassembly
Install Governor Shafts, Seal, and Governor Gear (Mechanical Governor only)
Governor Components and Details
B
A
C
D
E
A Crankcase Surface B
C Oil Seal D
E Crankcase Surface F
If governor shafts, seal, and/or governor gear were removed, reassemble as follows.
1. Lightly oil lip and outside diameter of new governor cross shaft seal. Install seal into crankcase to depth shown.
2. If governor gear shaft was removed, press or lightly tap replacement shaft into oil pan to depth shown.
3. Lubricate governor cross shaft bearing surfaces in crankcase with engine oil. Insert governor cross shaft end with fl at cutout where governor yoke is secured, into crankcase and position shaft so that at part is visible (up).
4. Attach governor yoke to cross shaft so curved section is up as marked. Secure with screws. If a thread locking compound is not preapplied, apply a small amount of Loctite® 266™ Threadlocker or equivalent, to screw threads before installing. Torque screws to 2.2 N·m (20 in. lb.).
5. Install fi rst regulating pin with head down so it will contact yoke. Install governor gear with second regulating pin and fl yweight assembly in/down onto governor shaft until it locks into position. Apply a small amount of grease to locking tab thrust washer and install on top of governor gear so tang is facing up in 6 o’clock position.
F
Seal Depth
1.5-2.0 mm
(0.059-0.078 in.)
12.66 mm (0.498 in.)
Governor Gear
Shaft
Install Crankshaft
Carefully slide fl ywheel end of crankshaft through oil seal in crankcase.
Install Connecting Rods with Pistons and Rings
Piston Details
C
A B
A Side 1 B Side 2
C Top of Piston
NOTE: Cylinders are numbered on crankcase. Make
sure to install piston, connecting rod and end cap into appropriate cylinder bore as previously marked at disassembly. Do not mix end caps and connecting rods.
NOTE: Proper orientation of piston/connecting rod
assemblies inside engine is extremely important. Improper orientation can cause extensive wear or damage. Be certain pistons and connecting rods are assembled exactly as shown.
1. Stagger piston rings in grooves until end gaps are 120° apart. Oil ring rails should also be staggered.
2. Lubricate cylinder bore, piston, and piston rings with engine oil. Compress rings of piston side 1 using a piston ring compressor.
3. Lubricate crankshaft journals and connecting rod bearing surfaces with engine oil.
4. Make sure FLY stamping on piston is facing toward ywheel side of engine. Use a hammer with a rubber grip and gently tap piston into cylinder. Be careful oil ring rails do not spring free between bottom of ring compressor and top of cylinder.
5. Install inner rod cap to connecting rod using screws. Torque screws in increments to 11.6 N·m (103 in. lb.). Illustrated instructions are provided in service rod package.
Align chamfer of connecting rod with chamfer of its
mating end cap. When installed, fl at faces of connecting rods should face each other. Faces with raised rib should be toward outside.
6. Repeat this procedure for other connecting rod and piston assembly.
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Page 85
Reassembly
Install Camshaft
1. Liberally apply camshaft lubricant to each cam lobe. Lubricate camshaft bearing surfaces of crankcase and camshaft with engine oil.
2. Position timing mark of crankshaft gear at 12 o’clock position.
3. Slide camshaft into bearing surface of crankcase, positioning timing mark of camshaft gear at 6 o’clock position. Make sure camshaft gear and crankshaft gear mesh, with both timing marks aligned.
Determining Camshaft End Play
1. Place a new oil pan gasket into position on crankcase.
2. Position camshaft end play checking tool over camshaft. Use a feeler gauge to check end play between camshaft and end play checking tool. Camshaft endplay should be between 0.3/1.3 mm (0.011/0.051 in.).
3. No shim is typically used from factory. However, if camshaft end play is not within specifi ed range, remove checking tool and shim as necessary.
Several color coded shims are available:
White: 0.69215/0.73025 mm (0.02725/0.02875 in.)
Blue: 0.74295/0.78105 mm (0.02925/0.03075 in.)
Red: 0.79375/0.83185 mm (0.03125/0.03275 in.)
Yellow: 0.84455/0.88265 mm (0.03325/0.03475 in.)
Green: 0.89535/0.99345 mm (0.03525/0.03675 in.)
Gray: 0.94615/0.98425 mm (0.03725/0.03875 in.)
Black: 0.99695/1.03505 mm (0.03925/0.04075 in.)
4. Reinstall end play checking tool and recheck end play.
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Page 86
Reassembly
Breather/Oil Pan Components
M
L
K
D
F
J
E
I
C
F
H
A
N
A Oil Pan B Gerotor Gears C Oil Pump O-Ring D Oil Pump Housing
E Pickup Tube F Inlet Seal G Pickup Screen H Drain Plug
Crankshaft Bearing
I
M Breather Assembly N Oil Seal
(PTO)
J Oil Pan Gasket K Breather Filter L Breather Gasket
G
B
Breather Fastener
Torque Sequence
1
4
3
2
Install Oil Pan Seal and Crankshaft Bearing (PTO)
If bearing was removed in servicing, install a new bearing using an arbor press and driver.
1. Make sure oil pan bore for bearing is clean, dry and free of nicks or burrs.
86 62 690 05 Rev. --KohlerEngines.com
2. Press crankshaft bearing (PTO) in place with notch oriented in 12 o’clock position using an arbor press and driver. Make sure bearing is fully seated against ange.
3. Apply a light coat of clean engine oil to inner surface of bearing.
Page 87
Reassembly
PTO Oil Seal Details
A
B
A 3.0 mm (0.118 in.) B Oil Seal
1. Check to make sure there are no nicks or burrs in crankshaft seal bore of oil pan.
2. Lightly oil outside diameter of oil seal.
3. Install oil seal into oil pan using a seal driver. Make sure oil seal is installed straight and true in bore to depth shown.
Oil Pump Assembly
Oil pump is mounted inside oil pan. If service was required and oil pump was removed, refer to Disassembly/Inspection and Service procedure.
Install Oil Pan Assembly
Torque Sequence
1
3
14
5
12
1. Make sure sealing surfaces of oil pan and crankcase are clean, dry, and free of any nicks or burrs. Install a new O-ring in oil pan.
2. Install a new oil pan gasket onto crankcase.
3. Make sure oil pump and oil pick up are installed in oil pan.
4. Ensure end of locking tab washer on governor gear is positioned outward in 6 o’clock position inside crankcase.
5. Orient fl at of oil pump gear to match position of fl at on camshaft. Install oil pan to crankcase. Carefully seat camshaft and crankshaft into their mating bearings. Rotate crankshaft slightly to help oil pump and governor gears mesh.
6. Lightly oil threads and install screws securing oil pan to crankcase. Torque fasteners in sequence shown to 25.6 N·m (227 in. lb.).
Check Crankshaft End Play
Set engine on base and use a dial indicator to check crankshaft end play to 0.30/1.50 mm (0.011/0.059 in.).
Install Breather Assembly
1. Make sure sealing surfaces of crankcase and breather cover are clean and free of any nicks or burrs. Do not scrape surfaces, as this could result in leakage.
2. Install breather chamber gasket as shown. Assemble and install breather assembly components as illustrated. Make sure fi lter does not extend above top surface and all parts are properly aligned.
3. Install screws and torque to 12.4 N·m (110 in. lb.) following sequence.
4. Breather hose will be connected to cover in a later step.
7
9
11
13
2
10
8
6
4
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Page 88
Reassembly
Cylinder Head Components
C
B
G
H
A Gasket B Valve C Cylinder Head D Pipe Plug
E Guide Plate F Spacer G Washer H Spark Plug
I Valve Stem Seal J Valve Spring K Valve Spring Retainer L Hydraulic Lifter
M Valve Spring Keeper N Push Rod O Rocker Arm P Rocker Arm Pivots
Q Rocker Stud R Valve Cover Seal S Valve Cover T Grommet
U Rocker Arm Screw V
Non-adjustable Valve
D
E
F
I
A
Train (Non-AVT)
L
N
J
K
M
Q
O
P
X
W Adjusting Nut X
W
V
U
R
S
Adjustable Valve
T
Train (AVT)
Install Hydraulic Lifters
NOTE: Hydraulic lifters should always be installed in
same position as they were disassembled. Exhaust lifters are located on output shaft side of engine while intake lifters are located on fan side of engine. Cylinder numbers are embossed on top of crankcase and each cylinder head.
1. Refer to Disassembly/Inspection and Service for lifter preparation (bleed down) procedures.
2. Apply camshaft lubricant to bottom surface of each lifter. Lubricate hydraulic lifters and lifter bores in crankcase with engine oil. Do not prime lifters.
3. Note mark or tag identifying hydraulic lifters as either intake or exhaust and cylinder 1 or cylinder 2. Install hydraulic lifters into their appropriate location in crankcase. Do not use a magnet.
88 62 690 05 Rev. --KohlerEngines.com
Valve Stem Seals
These engines use valve stem seals on intake and exhaust valves. Always use new seals whenever valves are removed from cylinder head. Seals should also be replaced if worn or damaged. Never reuse an old seal.
Assemble Cylinder Heads
Prior to installation, lubricate all components with engine oil, paying particular attention to lip of valve stem seal, valve stems, and valve guides. Install in order listed below using a valve spring compressor.
Intake and exhaust valves
Valve spring retainers.
Valve springs.
Valve spring keepers.
Valve stem seals.
Guide plate (AVT only).
Pivot studs (AVT only).
Page 89
Reassembly
2
2
4
4
5
5
3
3
1
1
Install Cylinder Heads
Torque Sequence
2
5
4
3
1
12
NOTE: Match numbers embossed on cylinder heads
and crankcase.
1. Check to make sure there are no nicks or burrs on
sealing surfaces of cylinder head or crankcase.
2. Check dowel pins are in place in 2 lower locations,
and install a new cylinder head gasket, (printed side up).
3. Install cylinder head. Make sure head is fl at on
gasket and dowel pins. Install a fl at washer on screws in locations 1 and 3. Install spacer followed by a fl at washer on screw in location 5. Start 5 screws.
4. Torque screws in 2 stages, fi rst to 23.7 N·m
(210 in. lb.), fi nally to 46.9 N·m (415 in. lb.) following sequence shown.
5. Repeat procedure for opposite cylinder.
6. Make sure threads of pipe plugs for cylinder heads
are clean and dry. Install a plug into each cylinder head above screw on location 2 and torque to
28.5 N·m (252 in. lb.).
Install Guide Plate, Pivot Studs, Push Rods and Rocker Arms
NOTE: Install push rod guide plate so fl ange is down
(towards cylinder) on side 1, and up (away from cylinder) on side 2 (AVT only).
NOTE: Push rods should always be installed in same
position as before in disassembly.
Non-adjustable Valve Train
1. Position rocker arm pivots in sockets of rocker arms.
Insert screws through pivots, rocker arms, and guide plate. Start screws into cylinder head and fi nger tighten only at this time.
2. Note mark or tag identifying push rod as either
intake or exhaust and cylinder 1 or 2. Dip ends of push rods in engine oil and install, making sure each push rod ball seats in its hydraulic lifter socket. Align rocker arms over valve stems. Hold rocker arm in position and torque screws to 15.5 N·m (137 in. lb.).
5
2
4
3
1
Adjustable Valve Train
1. Install push rod guide plate and rocker arm pivot studs onto cylinder heads if removed previously. Torque studs to 11.3 N·m (100 in. lb.).
2. Note mark or tag identifying push rod as either intake or exhaust and cylinder 1 or 2. Dip ends of push rods in engine oil and install, making sure each push rod ball seats in its hydraulic lifter socket.
3. Apply grease to contact surfaces of rocker arms and rocker arm pivots. Install rocker arms, rocker arm pivots, and adjusters on cylinder head 1.
Adjust Valve Clearance (AVT Only)
NOTE: It takes two hands to make lash adjustment. A
clamping device or an assistant to hold lifter compressed while making adjustment will make process easier.
1. Turn adjusters in rocker arms by hand clockwise (down), only enough to capture push rods in recesses.
2. Rotate crankshaft to establish TDC on compression stroke for cylinder 1.
Check for: a. Compression will be felt through spark plug hole. b. Keyway of crankshaft will be aligned with cylinder
1.
c. No rocker arm/push rod movement if crankshaft
is rotated slightly back and forth. If they are moving, rotate crankshaft one full revolution.
3. Pre-Bled Lifters:
a. Apply downward pressure to push rod side of
rocker arm to compress lifter and bottom internal plunger. Several manual compressions may be necessary. Hold in this position for step 3b.
b. Insert a 0.406/0.483 mm (0.016/0.019 in.) feeler
gauge between end of one valve and rocker arm. Turn adjuster until a slight drag is felt. Hold adjuster in this position and tighten locking setscrew. Torque setscrew to 7.7 N·m (69 in. lb.). After tightening recheck adjustment. Proper valve
clearance is 0.406/0.483 mm (0.016/0.019 in.). c. Repeat procedure for other valve on this side. Non-Bled Lifters (when cylinder heads and lifters are
not removed):
a. Turn 1 rocker arm adjusting nut from side 1 down
until push rod is snug but can be rotated with
drag. This is 0 lash. b. Mark or note setting of adjustment nut, then turn
(tighten) adjuster nut 3 complete revolutions
clockwise, plus one fl at of nut (3/4 turn), or a total
of 3-3/4 turns. c. Hold adjuster nut in this position and tighten
locking setscrew. Torque setscrew to 7.7 N·m (69
in. lb.). d. Repeat procedure for other valve on this side.
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Reassembly
4. Viewed from PTO end, rotate crankshaft 270° (3/4 turn) counterclockwise and align crankshaft keyway with cylinder 2, which now puts that cylinder at TDC on compression stroke.
5. Repeat steps 3-5 for setting valve clearance on cylinder 2.
6. Rotate crankshaft to check for free operation of valve train. Check for clearance between valve spring coils at full lift, or bending of push rod(s) can occur. Minimum allowable clearance is 0.25 mm (0.010 in.).
Check Assembly
Rotate crankshaft a minimum of two revolutions to check assembly and overall proper operation.
Check if engine can be turned over completely and compression is noted. If it cannot (locks up at some point), return piston to TDC between intake and exhaust strokes fi rst for one cylinder and then other waiting ten minutes to allow lifters to bleed down, then check for compression again.
Install Valve Covers
1. Make sure sealing surfaces are clean and free of any nicks or burrs.
2. Install and properly seat seal onto each valve cover.
3. Install valve covers on same side as they were originally installed.
4. Install a new grommet on each valve cover mounting screw. Start each screw into hole.
5. Check position of each cover and seal, then torque screws to 13.6 N·m (120 in. lb.).
Install Spark Plugs
1. Check gap using wire feeler gauge. Adjust gap to
0.76 mm (0.030 in.).
2. Install plug into cylinder head.
3. Torque plug to 27 N·m (20 ft. lb.).
Oil Cooler/Filter Components
A
B
C
D
E
F
G
I
J
A Oil Filter B Oil Filter Nipple
C Cup D Valve Spring
E Cup Spring F Oil Filter Valve
G Screw H Oil Filter Housing
I Pin J O-Ring
Install Oil Filter Housing Assembly
Reassemble oil fi lter housing if disassembled previously.
Reassembly
1. Install small spring onto rubber valve, and insert small end through corresponding hole in cup until properly seated.
2. Install larger spring into fi lter housing.
3. Insert oil fi lter cup, aligning cutout with corresponding section in housing.
4. Install nipple in housing and torque to 17.8 N·m (158 in. lb.).
Installation
1. Make sure all sealing surfaces are clean and all dowel pins are in position. Install or check new O-rings are around all oil fi lter adapter dowel pins.
2. Install oil fi lter housing assembly and secure with M8 screw. Make sure housing is fl at on crankcase and all O-rings remain in position. Torque screw to
23.7 N·m (210 in. lb.)
3. Oil fi lter may be installed now or upon completion of engine assembly.
H
90 62 690 05 Rev. --KohlerEngines.com
Page 91
Reassembly
Backing Shroud/Intake Manifold/Throttle Body/Air Cleaner/Flywheel/Fan Assembly Components
G
A
B
C
D
E
F
H
K
L
I
J
M
N
O
P
A Special Washer B Debris Screen C Stiffener D Flywheel Screw
Backing Shroud/
E Washer F
Flywheel/Fan/Hex
Stud Assembly
G
Intake Manifold/
Air Cleaner
H Speed Sensor
Assembly
I Stator J
Rectifi er-Regulator
Connector
M Breather Hose N Oil Sentry
TM
K
O
MAP Sensor
Connector
Oil Temperature
Sensor
L Ground Lead
P Reducer Bushing
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Page 92
Reassembly
Install Intake Manifold/Throttle Body//Air Cleaner/ Backing Shroud Assembly
Intake Manifold Torque Sequence
3
4
1
2
1. Install new intake manifold gaskets on bolts so notched section is inward and points toward fl ywheel side. Loosely assemble intake manifold to heads; do not tighten as this time.
2. Set backing shroud assembly onto crankcase and start mounting screws. Torque screws in a crisscross pattern to 10.7 N·m (95 in. lb.) into new holes, or 7.3 N·m (65 in. lb.) into used holes.
3. Apply pipe sealant with Tefl on® (Loctite® PST® 592™ Thread Sealant or equivalent) to stator mounting holes.
4. Position stator, aligning mounting holes so leads are at bottom and toward rectifi er-regulator mount on cylinder 1 side.
5. Install and torque screws to 9.3 N·m (82 in. lb.).
6. Check that stator wires are under molded clips in backing shroud assembly.
7. Install dipstick tube with a new lower O-ring into crankcase. Secure with lower mounting screw. Torque screw to 7.7 N·m (68 in. lb.). Start upper screw but do not tighten until after blower housing is installed.
8. Torque intake manifold screws in 2 stages using sequence shown, fi rst to 16.9 N·m (150 in. lb.), nally to 22.6 N·m (200 in. lb.).
Install Breather Hose
1. Lightly oil lower end of breather hose and install into hole in breather assembly. Cover should be situated between 2 raised rings of hose.
2. Connect Oil Sentry™ lead (green wire).
3. Install oil temp sensor connector.
4. Install MAP sensor connector.
Install Oil Cooler
NOTE: New hose clamps are recommended for
reassembly, or if clamps have been loosened (expanded) several times to avoid leakage.
1. Connect hoses between oil fi lter adapter and oil cooler. Secure with new clamps.
2. Align oil cooler with bosses in backing shroud assembly. Secure with screws and washers but do not tighten at this time.
Install Ground Lead and Rectifi er-Regulator Connector
1. Attach ground lead to outer rectifi er-regulator mounting screw and washer, then torque mounting screw to 2.5 N·m (22 in. lb.).
2. Install wiring harness clamp mounting bracket with harness ground lead to inboard #1 side cylinder boss.
3. Install rectifi er-regulator connector.
Install Flywheel/Fan Assembly
CAUTION
Damaging Crankshaft and Flywheel can cause personal injury.
Using improper procedures can lead to broken fragments. Broken fragments could be thrown from engine. Always observe and use precautions and procedures when installing fl ywheel.
NOTE: Before installing fl ywheel make sure crankshaft
taper and fl ywheel hub are clean, dry, and completely free of any lubricants. Presence of lubricants can cause fl ywheel to be over stressed and damaged when screw is torqued to specifi cations.
NOTE: Make sure fl ywheel key is installed properly in
keyway. Flywheel can become cracked or damaged if key is not properly installed.
1. Install woodruff key into crankshaft keyway. Make sure key is properly seated and parallel with shaft taper.
2. Set fl ywheel/fan assembly onto crankshaft, being careful not to shift woodruff key.
3. Install screw and washer.
4. Use a fl ywheel strap wrench or holding tool to hold ywheel. Torque screw to 69.8 N·m (51 ft. lb.).
Install Crankshaft Position Sensor
NOTE: Ensure all parts are clean, undamaged, and free
of debris; make sure electrical connectors have seal in place.
1. Install crankshaft position sensor and bracket assembly to crankcase posts.
2. Snug screws and check air gap of sensor with a feeler gauge. It must be 0.20-0.70 mm (0.008-0.027 in.).
3. Torque bracket screws to 9.7 N·m (86 in. lb.).
4. Check electrical connector on crankshaft position sensor making sure a good connection is made.
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Page 93
External Engine Components
M
N
L
K
O
Reassembly
S
S
R
Q
P
H
D
A
I
B
J
A Dipstick B Oil Drain Plug C Oil Fill Tube D Valley Baf e
E Spark Plug Lead F Barrel Baf e G Starter Assembly H Ignition Coil
Fuel Pump Module
I
M Electrical Connector N Evap Line O
Q Oil Filter R
U Gasket V Carburetor W Intake Manifold
Bracket
F
B
E
F
G
J Fuel Filter K Fuel Pump Module L Fuel Pump
High Pressure Fuel
Line Connector
Blower Housing with
Fixed Guard
S Cylinder Shroud
C
P Oil Cooler
D
9362 690 05 Rev. -- KohlerEngines.com
Page 94
Reassembly
Install Valley and Cylinder Barrel Baffl es
1. Install #1 side valley baffl e and secure with 3 screws. Reinstall clip securing harness to baffl e. Install #2 side valley baffl e and secure with 3 screws. Torque M6 screws going into cylinder head and crankcase to 10.7 N·m (95 in. lb.) for new holes, or 7.3 N·m (65 in. lb.) for used holes.
2. Install cylinder barrel baffl es. Make sure spark plug lead is routed through corresponding opening in each baffl e. Start each screw. Torque M6 shoulder screws going through backing shroud assembly into extruded holes in baffl es to 2.5 N·m (22 in. lb.) into new holes, or 2.0 N·m (18 in. lb.) into used holes. Torque M6 screws going into cylinder head and crankcase to 10.7 N·m (95 in. lb.) for new holes, or
7.3 N·m (65 in. lb.) for used holes.
Torque Oil Cooler Screws
1. Align oil cooler with bosses in backing shroud assembly. Torque screws to 2.3 N·m (21 in. lb.).
Install Fuel Pump Module/Fuel Pump Assembly
NOTE: Ensure all parts are clean, undamaged, and free
of debris; make sure electrical connector has seal in place.
NOTE: Fuel pump module pins should be coated with a
thin layer of electrical grease to prevent fretting and corrosion and may be reapplied if fuel pump module is being reused.
1. Orient fuel pump module baffl e so pulse fi tting in crankcase extends through cutout in baffl e.
2. Connect pulse line (from fuel pump) to crankcase tting.
3. Install screws to secure fuel pump module/baffl e assembly to crankcase. Torque screws to 11.9 N·m (105 in. lb.). If fuel pump module was removed from baffl e, after installing baffl e, install fuel pump module to baffl e and torque screws to 9.2 N·m (81 in. lb.).
4. Connect electrical connector to top of fuel pump module. Ensure grey locking tab is pulled out before connecting. Push connector onto terminal until a click us heard, then push in grey locking tab to lock connector.
5. Push high pressure fuel line connector onto fuel pump module fi tting.
6. If Oetiker clamp was cut to remove inlet fuel line, slide a new Oetiker clamp onto fuel line and connect fuel line to fuel pump module. Only use an Oetiker clamp pliers to crimp Oetiker clamps. Oetiker clamp crimp must point up and away from top of fuel pump module and anti-abrasion sleeve must be positioned over Oetiker clamp.
7. Install connectors to #1 and #2 side ignition coils.
8. Orient/push line clamps into baffl es. Push evap line into clips on high pressure fuel line. Connect evap line to vent fi tting on fuel pump module.
Install Electric Starter
1. Install electric starter motor using screws.
2. Torque screws to 16 N·m (142 in. lb.).
3. Connect main power lead and solenoid lead.
Install Cooling Fan and Debris Screen
CAUTION
Failure to utilize or reassemble debris screen as designed could result in debris screen failure and serious personal injury.
If cooling fan was removed from fl ywheel perform step 1; if hex studs were removed from fl ywheel perform step 2; otherwise proceed to step 3.
1. Position cooling fan onto fl ywheel aligning mounting locations. Apply a small amount of Loctite® 243™ Threadlocker to threads and install long mounting screws. Torque screws to 10.4 N·m (92 in. lb.).
2. Apply a small amount of Loctite® 243™ Threadlocker to external threaded section, (unless new parts with preapplied locking compound are being used). Thread debris screen hex studs into mounting holes in fl ywheel. Torque each stud to 21.5 N·m (190 in. lb.).
3. Install stiffener followed by metal debris screen onto studs. Secure with special washers and mounting screws using Loctite® 243™ Threadlocker on threads. Torque hex fl ange screws to 20.3 N·m (180 in. lb.) and button head cap screws to 9.9 N·m (88 in. lb.).
Install Blower Housing/Guard Assembly
Align and install blower housing with fi xed guard. Secure with screws. Torque screws to 2.5 N·m (22 in. lb.) into new holes, or 2.0 N·m (18 in. lb.) into used holes.
Install Fuel Pump
Install fuel pump to blower housing and secure with screws. Torque screws to 2.8 N·m (25 in. lb.).
Install Cylinder Shrouds
Install cylinder shrouds and secure with screws. Torque screws to 2.5 N·m (22 in. lb.) into new holes, or 2.0 N·m (18 in. lb.) into used holes.
94 62 690 05 Rev. --KohlerEngines.com
Page 95
Mechanical Governor Control Bracket Components
B
Reassembly
A
C
A Throttle Lever B Control Bracket C Throttle Linkage D Linkage Spring
E Cross Shaft F Governor Lever G Governor Spring H Idle Spring
Install Governor Lever (Mechanical Governor Only)
Install governor lever onto governor shaft and connect throttle linkage with black clip.
Adjusting Mechanical Governor
1. Position governor lever so clamping area is inboard but completely on knurled area of governor cross shaft.
2. Move governor lever toward throttle body as far as it will go (wide-open throttle) and hold in position.
3. Insert a long thin rod or tool into hole on cross shaft and rotate shaft clockwise (viewed from end) as far as it will turn, then torque nut to 7.1 N·m (63 in. lb.).
4. Connect governor spring (with long looped end), to inner hole on governor lever and control bracket.
Connect governed idle spring to outer governor lever
hole and control bracket.
Make sure springs do not contact valley baffl e.
D
E
F
G
Install Oil Sentry™ (if equipped)
1. Apply pipe sealant with Tefl on® (Loctite® PST® 592™ Thread Sealant or equivalent) to Oil Sentry™ threads switch and install it into 1/8 in. port in oil pan. Torque switch to 10.7 N·m (95 in. lb.).
2. Connect green wire lead to Oil Sentry™ terminal.
Install Muffl er
1. Install new exhaust gaskets onto exhaust studs.
2. Install port liners (if equipped). Attach muffl er and secure with nuts onto exhaust studs. Torque nuts to
24.4 N·m (216 in. lb.).
3. Install any attaching hardware and brackets. Torque M6 screws to 9.9 N·m (88 in. lb.), and M8 screws to
24.4 N·m (216 in. lb.).
4. Install spark arrestor (if used).
H
9562 690 05 Rev. -- KohlerEngines.com
Page 96
Reassembly
Install Oil Filter and Add Oil to Crankcase
NOTE: Make sure both oil drain plugs are installed and
torqued to 21.4 N·m (16 ft. lb.). to prevent oil leakage.
1. Install oil drain plugs. Torque plugs to 21.4 N·m (16 ft. lb.).
2. Place new fi lter in shallow pan with open end up. Fill with new oil until oil reaches bottom of threads. Allow 2 minutes for oil to be absorbed by fi lter material.
3. Apply a thin fi lm of clean oil to rubber gasket on new lter.
4. Refer to instructions on oil fi lter for proper installation.
5. Fill crankcase with new oil. Level should be at top of indicator on dipstick.
6. Reinstall oil fi ll cap/dipstick and tighten securely.
Connect Spark Plug Leads
Connect leads to spark plugs.
Prepare Engine for Operation
NOTE: If ECU, throttle body, TPS, or fuel pump module
were replaced, an ECU Reset and TPS Learn is required. Refer to Electronic Fuel Injection (EFI) System section.
NOTE: If electronic governor and throttle body were
removed or replaced, refer to Governor section for proper adjustment/assembly.
Engine is now completely reassembled. Before starting or operating engine, follow proceeding steps.
1. Make sure all hardware is tightened securely.
2. Make sure oil drain plugs, Oil Sentry switch, and a new oil fi lter are installed.
pressure
3. Verify crankcase has been fi lled with correct amount, weight, and type of oil. Refer to oil recommendations and procedures in Maintenance, Specifi cations, and Lubrication System sections.
4. Turn on fuel supply.
Testing Engine
It is recommended engine be operated on a test stand or bench prior to installation in equipment.
1. Set engine up on a test stand. Install an oil pressure gauge. Start engine and check to be certain oil pressure (20 psi or more) is present. Run engine at idle for 2-3 minutes, then 5-6 minutes more between idle and midrange.
2. Adjust idle speed screw located on throttle body as necessary. Standard idle speed setting for EFI engines is 1500 RPM, but certain applications might require a different setting.
3. Mechanical Governor: Adjust governed idle and high speed (RPM) to required settings. Make sure maximum engine speed does not exceed 3900 RPM (no load).
3. Electronic Governor: Attach 12 volt jumper wire to speed control input red wire with yellow tracer. Engine speed should increase to high. Make sure maximum engine speed does not exceed 3900 RPM (no load). If engine speed does not increase, refer to Governor section for proper troubleshooting and diagnostics.
96 62 690 05 Rev. --KohlerEngines.com
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