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

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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 17 Tools and Aids 20 Troubleshooting 24 Air Cleaner/Intake 25 Electronic Fuel Injection (EFI) System 54 Governor System 80 Lubrication System 82 Electrical System 87 Starter System 91 Disassembly/Inspection and Service

112 Reassembly

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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 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.

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. Never run engine indoors or in enclosed spaces.

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

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

WARNING

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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 ﬁ 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 ﬁ lter.

● Check oil cooler ﬁ 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 500 Hours or Annually¹

● Replace spark plugs and set gap. Electrical System

Every 600 Hours

● Replace air cleaner inner element. Air Cleaner/Intake

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).

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Maintenance

°F -20 020324060

50 80 100

°C -30 -20 -10 0 10 20 30 40

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.

RECOMMENDATIONS

FUEL

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.

NOTE: E15, E20 and E85 are NOT approved and

should NOT be used; eﬀ ects 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 overﬁ ll fuel tank.

● Do not use gasoline older than 30 days.

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Engine Dimensions - Flywheel Side

Speciﬁ cations

A 484.6 mm (19.08 in.) B

E 99.6 mm (3.92 in.) F

Oil Level Dipstick

M 62.7 mm (2.47 in.) N

and Fill

93.5 mm (3.68 in.) Air Filter Cover

Assembly Removal

503.4 mm (19.82 in.) Air Filter Element

Removal

17.3 mm (0.68 in.) Spark Plug Lead

J Mounting Hole "A" K

20.7 mm (0.82 in.) Spark Plug Lead

KohlerEngines.com

C 267.4 mm (10.53 in.) D 152.5 mm (6.00 in.)

G Cylinder #1 Shroud H

89.8 mm (3.54 in.) Oil Filter

325.3 mm (12.81 in.)

Oil Filter

L Centerline Engine

P 560.3 mm (22.06 in.)

30.0 mm (1.18 in.)

Cylinder #1 Shroud

Removal

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Speciﬁ cations

Engine Dimensions - PTO Side (Earlier Design)

A 428.1 mm (16.86 in.) B 45° C 55° D 35°

2X Ø 35 mm (1.38 in.)

M 89.8 mm (3.54 in.) N 275.2 mm (10.84 in.) O

Muﬄ er Gasket

M8 X 1.25-6H 25 mm

(0.98 in.) Deep 7

Holes

J Rotation Direction K 89.8 mm (3.54 in.) L Mounting Hole "A"

60 mm (2.36 in.)

Exhaust Port #2

M8 X 1.25 mm

4 Studs

60.0 mm (2.36 in.) Exhaust Port #1

H Ø 254.0 mm (10.0 in.)

P 124.2 mm (4.89 in.)

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Engine Dimensions - PTO Side (Later Design)

Speciﬁ cations

A 428.1 mm (16.86 in.) B 45° C 35° D

M 275.2 mm (10.84 in.) N

60 mm (2.36 in.)

Exhaust Port #2

I Rotation Direction J 89.8 mm (3.54 in.) K Mounting Hole "A" L 89.8 mm (3.54 in.)

M8 X 1.25 mm

4 Studs

60.0 mm (2.36 in.) Exhaust Port #1

KohlerEngines.com

Ø 254.0 mm (10.0

O 124.2 mm (4.89 in.)

in.)

2X Ø 35 mm (1.38 in.)

Muﬄ er Gasket

3/8-16 UNF-2B Inch

30 mm (1.18 in.) Deep 4 Holes

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Speciﬁ cations

Engine Dimensions - Starter Side

L K

A 680.8 mm (26.80 in.) B

E 80.2 mm (3.16 in.) F

I Mounting Hole "A" J

M Grass Screen N Cylinder #1 Shroud O

93.5 mm (3.68 in.) Exhaust Port #1

6.4 mm (0.25 in.) Square Keyway

156.2 mm (6.15 in.) Cylinder #1 Shroud

Removal

C Oil Pressure Switch D

7/16-20 UNF-2B Inch

38.1 mm (1.50 in.) Deep

K 389.8 mm (15.35 in.) L 423.2 mm (16.66 in.)

50.0 mm (1.97 in.)

Oil Filter Removal

H Ø 28.6 mm (1.13 in.)

Engine Mounting

Surface

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Engine Dimensions - Opposite Starter Side

Speciﬁ cations

A Lifting Point B Cylinder #2 Shroud C Access to Oil Cooler D

E Lifting Point F

I 652.3 mm (25.68 in.) J

M Muﬄ er (optional)

Fuel Filter

Fits 6.4 mm (0.25 in.)

Fuel Line

Oil Drain Plug

1/2 NPT Inch

70.5 mm (2.78 in.)

Exhaust Port #2

Engine Mounting

Surface

156.2 mm (6.15 in.) Cylinder #2 Shroud

Removal

H Mounting Hole "A"

L 2.6 mm (0.10 in.)

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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 . . . . . . . . . . . . . . . . . . . . . 4623500328

Year Manufactured Code Factory Code

Code Year

46 2016 47 2017 48 2018

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) 1.9-2.6 L (2.0-2.7 U.S. qt.) Maximum Angle of Operation (@ full oil level)

TORQUE SPECIFICATIONS

3,5

25°

ECV940 ECV980

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.)

ﬁ 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 (Engines with

7.3 N·m (65 in. lb.)

Separate MAP and Intake Air Temperature Sensors) Temperature/Manifold Absolute Pressure (TMAP) Sensor Fastener

7.3 N·m (65 in. lb.)

(Engines with Combined Sensor)

Values are in Metric units. Values in parentheses are English equivalents.

Exceeding maximum angle of operation may cause engine damage from insuﬃ cient lubrication.

Lubricate threads with engine oil prior to assembly.

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.

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Speciﬁ cations

TORQUE SPECIFICATIONS

3,5

ECV940 ECV980

Connecting Rod

Cap Fastener (torque in increments) 11.6 N·m (103 in. lb.)

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.)

ﬁ 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

Fastener 9.9 N·m (88 in. lb.) 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.) Front Drive Shaft Screw (into ﬂ ywheel) 24.4 N·m (216 in. lb.)

Flywheel

Fan Fastener Screw - Truss Head 10.4 N·m (92 in. lb.) Fan Fastener Screw - Hex Head 9.9 N·m (88 in. lb.) Flywheel 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.) 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.)

Values are in Metric units. Values in parentheses are English equivalents.

Lubricate threads with engine oil prior to assembly.

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Speciﬁ cations

TORQUE SPECIFICATIONS

3,5

ECV940 ECV980

Igniton Continued

Crankshaft Position Sensor Earlier Design Bracket

Crankshaft Position Sensor to Bracket Screw 11.3 N·m (100 in. lb.)

Crankshaft Position Sensor Bracket to Crankcase Screw 9.7 N·m (86 in. lb.)

Crankshaft Position Sensor Later Design Bracket

Crankshaft Position Sensor to Bracket Screw 6.8 N·m (60 in. lb.)

Crankshaft Position Sensor Bracket to Crankcase Screw 7.3 N·m (65 in. lb.)

Lifter Feed Chamber Cover

Screw 6.6 N·m (58 in. lb.)

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

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.)

Values are in Metric units. Values in parentheses are English equivalents.

Lubricate threads with engine oil prior to assembly.

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Speciﬁ cations

TORQUE SPECIFICATIONS

3,5

ECV940 ECV980

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.)

CLEARANCE SPECIFICATIONS

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) Thrust Bearing (Flange) Non-Thrust Bearing

0.30/1.50 mm (0.011/0.059 in.)

0.20/0.94 mm (0.008/0.037 in.)

Values are in Metric units. Values in parentheses are English equivalents.

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Speciﬁ cations

CLEARANCE SPECIFICATIONS

ECV940 ECV980

Crankshaft Continued

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.)

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.)

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.)

Values are in Metric units. Values in parentheses are English equivalents.

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Speciﬁ cations

CLEARANCE SPECIFICATIONS

ECV940 ECV980

Ignition

Spark Plug Gap 0.76 mm (0.030 in.) Crankshaft Position Sensor Air Gap (only on earlier design sensor

0.2/0.7 mm (0.008/0.027 in.)

bracket) Crankshaft Position Sensor Max. Air Gap (only on later design

2.794 mm (0.110 in.)

sensor bracket)

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.)

Thrust Face O.D.

New Max. Wear Limit

Piston Thrust Face-to-Cylinder Bore

Running Clearance

0.30/0.55 mm (0.011/0.021 in.)

0.94 mm (0.037 in.)

89.953/89.967 mm (3.5414/3.5420 in.)

89.925 mm (3.540 in.)

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°

Values are in Metric units. Values in parentheses are English equivalents.

Measure 11 mm (0.4331 in.) above bottom of piston skirt at right angles to piston pin.

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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

Property Class

8.8

10.9 12.9

Noncritical

Fasteners

Into Aluminum

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)

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

62 690 05 Rev. EKohlerEngines.com

Page 17

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. NOTE: Not all tools listed are required to service this engine.

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 Code Plug, Red Wire Code Plug, Blue Wire Shrader Valve Adapter Hose Wire Probe Set (2 pieces regular wire with clip; 1 piece fused wire) Hose Removal Tool, Dual Size/End (also sold as individual Kohler tool) K-Line Adapter Jumper Lead Wiring Harness

Kohler Wireless Diagnostic System Module (Bluetooth®)

For wireless Android EFI diagnostics. Individual component available: Wireless Diagnostic System Interface Cable

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-027 DTI-029 DTI-037 DTI-031 DTI-033

Kohler 25 176 23-S Kohler 25 761 45-S

Kohler 25 761 44-S

1762 690 05 Rev. E KohlerEngines.com

Page 18

Tools and Aids

TOOLS

Description Source/Part No.

E-Gov Jumper Test Tool

Used to test sealed GCU/wiring harness module on ECV940, ECV980 E-Gov engines.

Flywheel Puller

For properly removing ﬂ ywheel from engine.

Flywheel Anchor Bolts, Washers, Nuts Tool

Used with Flywheel Puller for properly removing ﬂ ywheel from 5400 Series engine.

Hose Removal Tool, Dual Size/End (also available in EFI Service Kit)

Used to properly remove fuel hose from engine components.

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.

Oﬀ set 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.

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)

Stepper Motor Controller Tool

For testing operation of stepper motor/Digital Linear Actuator (DLA).

Jumper Lead Tool

For use with Stepper Motor Controller Tool to test rotary stepper motor.

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.

Kohler 25 761 51-S

SE Tools KLR-82408

Kohler 25 086 753-S

Kohler 25 455 20-S

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 25 761 20-S Kohler 25 761 41-S

Design Technology Inc.

DTI-031R DTI-033R

Kohler 25 761 40-S

SE Tools KLR-82411

SE Tools KLR-82416

Kohler 25 455 21-S

Kohler 25 518 43-S

Kohler 28 761 01-S

Design Technology Inc.

DTI-K828

Kohler 25 455 12-S

Design Technology Inc.

DTI-K830

18 62 690 05 Rev. EKohlerEngines.com

Page 19

Tools and Aids

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 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.

Kohler 25 597 07-S

Only oxime-based, oil resistant RTV sealants, such as those listed, are approved

for use. Permatex® the Right Stuﬀ ® 1 Minute Gasket™ or Loctite® Nos. 5900® or 5910® are recommended for best sealing characteristics.

Loctite® Ultra Black 598™

Loctite® Ultra Blue 587™

Loctite® Ultra Copper 5920™

Permatex® the Right Stuﬀ ® 1

Minute Gasket™

Spline Drive Lubricant Kohler 25 357 12-S

FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL

51360

Loctite® 5910

A ﬂ ywheel holding tool can be made out of an old junk ﬂ 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 ﬂ 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.

1962 690 05 Rev. E KohlerEngines.com

Page 20

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 EFI 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.

● Clogged fuel line or fuel ﬁ lter.

● 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.

● Insuﬃ 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).

● Spark plug lead(s) disconnected.

Engine Starts But Does Not Keep Running

● Faulty cylinder head gasket.

● Faulty or misadjusted 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 ﬁ lter.

● Engine overheated.

● Faulty ACR mechanism (Retractable Start).

● Faulty or misadjusted 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 (Retractable Start).

● Seized internal engine components.

Engine Runs But Misses

● Engine overheated.

● Faulty spark plug(s).

● Ignition coil(s) faulty.

● 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 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.

● High crankcase oil level.

● Lean fuel mixture.

● Low crankcase oil level.

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).

20 62 690 05 Rev. EKohlerEngines.com

Page 21

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 overﬁ 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 throttle body 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 ﬂ 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.

2162 690 05 Rev. E KohlerEngines.com

Page 22

Troubleshooting

CRANKCASE VACUUM TEST

WARNING

Carbon Monoxide can cause severe nausea, fainting or death.

Avoid inhaling exhaust fumes. Never run engine indoors or in enclosed spaces.

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 (inches of water gauge only). 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 (inches of water gauge only):

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

22 62 690 05 Rev. EKohlerEngines.com

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.

Page 23

Troubleshooting

COMPRESSION TEST

A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug before removing it. Be sure battery is fully charged, unplug ECU, and throttle is wide open during test. Compression should be at least 160 psi and should not vary more than 15% between cylinders.

Some models (retractable start) 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.

2362 690 05 Rev. E KohlerEngines.com

Page 24

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 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.

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. EKohlerEngines.com24

Page 25

EFI SYSTEM

WARNING

Explosive Fuel can cause ﬁ res and severe burns.

Do not ﬁ ll fuel tank while engine is hot or running.

Typical electronic fuel injection (EFI) system and related components include:

● Fuel pump module and lift pump.

● Fuel ﬁ 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). Earlier engines have a

contacting (brushes) TPS. Later engines have a contactless (magnetic) TPS.

● Crankshaft position sensor.

● Oxygen sensor.

● Earlier engines have a separate manifold absolute

pressure sensor (MAP) and an intake air temperature (IAT) sensor (located in throttle body).

● Later engines have a combined temperature/manifold

absolute pressure (TMAP) sensor.

● Malfunction indicator light (MIL) - optional.

● 30 Amp fuse (charging system)

● 10 Amp fuse (ignition switch)

● 10 Amp fuse (battery power)

● Wire harness assembly & aﬃ liated wiring.

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 Electronic 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 50-60°C (122-140°F).

● Oxygen sensor has warmed suﬃ 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 and learn 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 60-70°C (140-158°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.

62 690 05 Rev. E KohlerEngines.com

Page 26

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 ﬂ 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 diﬀ erently 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 Bracket

A Earlier Design Bracket B Later Design Bracket

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 with earlier design bracket is mounted 0.20-0.70 mm (0.008-0.027 in.) from ﬂ ywheel. Later design bracket requires no adjustment.

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 ﬂ 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.

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EFI SYSTEM

Earlier engines have a separate intake air temperature (IAT) sensor (located in throttle body) and a manifold absolute pressure (MAP) sensor. Later engines have a combined temperature/manifold absolute pressure (TMAP) sensor.

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.

Manifold absolute pressure (MAP) sensor provides immediate manifold pressure information to ECU. MAP measures diﬀ erence 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.

Later engines have a Temperature/Manifold Absolute Pressure (TMAP) sensor. This is an integrated sensor that checks both intake air temperature and manifold absolute pressure. This combined sensor is located in intake manifold.

Oxygen sensor functions like a small battery, generating a voltage signal to ECU based upon diﬀ erence in oxygen content between exhaust gas and ambient air.

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 diﬀ erent 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.

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. Types of lift pumps are: a pulse fuel pump, a mechanical 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 kilopascals (39 psi).

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EFI SYSTEM

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 ﬁ 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.

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. Most 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, either a separate MAP sensor and an intake air temperature sensor, or a TMAP 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 diﬀ erent 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 diﬀ erent 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 Side

Pin # Function

1 Ignition Coil #1 Ground 2 Battery Ground 3 Diagnostic Communication Line 4 Crankshaft Position Sensor input 5 Fuel Injector Output #1 Ground 6 Fuel Injector Output #2 Ground 7 Oxygen Sensor Heater

Intake Air Temperature (IAT) sensor or TMAP

sensor input

9 Fuel Pump Ground

Ground for TPS, IAT and MAP sensors or TMAP

sensor, O2 and Oil sensors 11 MAP sensor or TMAP sensor input 12 Throttle Position Sensor (TPS) input 13 Crankshaft Position Sensor Ground 14 Oil Temperature Sensor input 15 Ignition Switch (Switched +12V)

Power for TPS sensor, MAP sensor or TMAP 16

sensor (+5V) 17 Oxygen Sensor (O2) input 18 Battery Power (Permanent +12V)

Grey Connector Side

Pin # Description

1 Not Used 2 Not Used 3 Malfunction Indicator Light (MIL) Ground 4 Not Used 5 Not Used 6 GCU Tach Output (Electronic Governor) 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

ECU

BLACK CONNECTOR SIDE GREY CONNECTOR SIDE

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 oﬀ sets, 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

M G

Intake Air

Crankshaft Position

Temperature Sensor

312

M F

G L

312

Sensor

Oil Temperature

only

Pressure Sensor

Manifold Absolute

Electronic Governor

D B

M B

Sensor

1018

EFI Wiring Diagram 6-Terminal Connector (engines with separate MAP sensor and intake air temperature sensor)

62 690 05 Rev. E KohlerEngines.com

B F

B G

AB AB ABC DABC 1 2 312ABC AB12

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

P 30A Fuse Q Battery R Fuel Pump S 6-Terminal Connector T Starter Motor

K White L Grey M Black N Stator O Rectiﬁ er-Regulator

Throttle Position

Z Fuel Injector #1 AA Fuel Injector #2 AB Ignition Coil #1 AC Ignition Coil #2 AD

U Oil Pressure Switch V MIL (Optional) W 10A Fuse X Black Connector Y Grey Connector

AE Oxygen Sensor AF

AJ Diagnostic Connector AK Grey/Blue AL

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EFI SYSTEM

M G

Sensor

Crankshaft Position

AI Diagnostic Connector

12312

312

AH AI

Sensor

Oil Temperature

312

M J

H F

D B

AG TMAP Sensor AH

EFI Wiring Diagram 6-Terminal Connector (engines with TMAP sensor)

1018

M B B

B F

Throttle Position

AB AB ABC DABC 1 2 A B C

only

Sensor

Electronic Governor

F Dark Green G Dark Blue H Purple I Pink J Ta n

A Red B Red/Black C Red/White D Yellow E Light Green

P 30A Fuse Q Battery R Fuel Pump S 6-Terminal Connector T Starter Motor

K White L Grey M Black N Stator O Rectiﬁ er-Regulator

Z Fuel Injector #1 AA Fuel Injector #2 AB Ignition Coil #1 AC Ignition Coil #2 AD

U Oil Pressure Switch V MIL (Optional) W 10A Fuse X Black Connector Y Grey Connector

AE Oxygen Sensor AF

AJ Grey/Blue AK

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EFI SYSTEM

Sensor

Crankshaft Position

AI Diagnostic Connector

J L M

E F

12312

CAB

Sensor

Oil Temperature

H D B F

AG TMAP Sensor AH

AL Red/Yellow AM Tan (MIL Ground)

B M

only

Sensor

Throttle Position

Electronic Governor

AB AB ABC ABC 1 2 DABC

G B F

DABC

1018

EFI Wiring Diagram 8-Terminal Connector (engines with TMAP sensor)

62 690 05 Rev. E KohlerEngines.com

F Dark Green G Dark Blue H Purple I Pink J Ta n

A Red B Red/Black C Red/White D Yellow E Light Green

P 30A Fuse Q Battery R Fuel Pump S 8-Terminal Connector T Starter Motor

K White L Grey M Black N Stator O Rectiﬁ er-Regulator

Z Fuel Injector #1 AA Fuel Injector #2 AB Ignition Coil #1 AC Ignition Coil #2 AD

U Oil Pressure Switch V MIL (Optional) W 10A Fuse X Black Connector Y Grey Connector

AE Oxygen Sensor AF

AJ Grey/Blue AK

Page 34

EFI SYSTEM

Crankshaft Position Sensor

A Earlier Design Bracket B Later Design Bracket

A sealed, non-serviceable assembly. If fault code P0337 is present and engine does not start/run, proceed to step

1. If P0337 is present and engine operates, clear codes and retest. If Fault Code diagnosis indicates a problem within this area, test and correct as follows.

1. Check mounting and air gap of crankshaft position sensor.

Earlier design bracket has slots to set air gap of

0.20-0.70 mm (0.008-0.027 in.). Later design bracket is not adjustable, but if gap is

greater than 2.794 mm (0.110 in.) check bracket or sensor for damage.

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, ﬂ 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)

Earlier engines were built with a contacting (brush) type TPS. Later engines are built with a contactless (magnet) type TPS. Both designs have same three wires attached; a 5 volt supply, a ground, and a signal wire. However, these designs are not interchangeable. Follow proper testing information based on sensor type.

Contacting (Brush) Type 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.

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. 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. b. Perform TPS Learn Procedure integrating new

sensor to ECU.

Between Terminal

A & C 3200-4100 Yes

A & C 4600-5200 Yes

Resistance

Value (Ω)

Continuity

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EFI SYSTEM

Contactless (Magnet) Type TPS

TPS is a sealed, non-serviceable assembly. If diagnosis indicates a bad sensor, complete replacement is necessary. Magnet that sensor detects is separate, and can be replaced or reused. If a blink code indicates a problem with TPS, it can be tested as follows:

Diagnostics of sensor: ECU will still have electrical faults captured in fault codes: P0122 & P0123. These electrical faults still have same meaning as with prior sensor, P0122 detecting low voltage, open circuit, and P0123 for high voltage conditions between ECU, wire harness, and sensor. Tip: when working with any electrical connection, remember to keep connections clean & dry. This is best accomplished by cleaning connection thoroughly prior to disassembly. Contaminated sensor connections can cause premature engine faults. Functionally testing sensor can no longer be done with simple resistance checks. If either of these two faults is present or a TPS fault is suspected, recommended diagnostic test is as follows:

If a computer with diagnostic software is available

Observe throttle percent and raw TPS values through diagnostic software. With diagnostic software communicating to ECU and key ON engine not running, these values can be observed while throttle is moved from closed to full open position. There should be a smooth and repeatable throttle percent value starting at closed position reading between 0 (about 6.5%) to WOT position reading 93 (100%). If one of these values is outside of speciﬁ ed range and output transitions in a smooth manner, reset ECU and run test again. Since there is no longer any wear elements inside sensor, most likely faults will be in electrical connections between sensor and wire harness and wire harness to ECU. With service software communicating to ECU and engine not running, a small load or gentle back and forth motion can be applied to connectors or wires just outside connectors to detect a faulty connection.

If only a volt meter is available Measure voltage supply to sensor from ECU. This

voltage should be 5.00 +/- 0.20 volts. This can be measured by gently probing terminals B & C on harness side with TPS connector removed from TPS and key ON. This will generate a P0122 fault that can be cleared with an ECU reset. If voltage is low, battery, harness and ECU should be investigated. If supply voltage is good, plug sensor back into harness. Probe sensor signal wire with volt meter, terminal A at TPS or pin Black 12 at ECU. This signal should start between 0.6-1.2 volts at low idle and grow smoothly as throttle is opened to

4.3-4.8 volts at full open (WOT). Since there is no longer any wear elements inside sensor, most likely faults will be in electrical connections between sensor and wire harness and wire harness to ECU.

Replace magnet assembly

A Magnet Assembly B

Magnet assembly is captured in a small plastic housing that is press ﬁ t to end of throttle shaft. This generally does not need replacement. If replacement is required, can be replaced as follows:

1. Remove sensor from throttle body, exposing round

magnet assembly.

2. A pair of ﬂ at blade screw drivers or a spanner tool

can be used to pry this oﬀ shaft. Caution should be used to avoid damage to machined ﬂ at surface that sensor seals against. Also, make sure throttle blade is in full open position to avoid driving throttle blade into throttle bore causing damage to blade and/or bore.

3. When replacing magnet assembly, alignment is

critical. There is a D-shaped drive feature on end of shaft and a matching pocket in magnet assembly. On outer diameter of magnet assembly is a notch that aligns with center of ﬂ at feature of D. Align this notch and ﬂ at of D feature in shaft and preassemble parts.

4. With throttle blade in full open position (WOT), press

magnet assembly fully on to throttle shaft. Full insertion can be checked by measuring height from throttle body sensor mounting face to end of magnet assembly. This should be no more than 8.6 mm (0.338 in.). Installation process requires signiﬁ cant force, so take care that all parts are aligned. Tapping magnet assembly on can fracture/damage brittle magnet within assembly and throttle body assembly and is NOT RECOMMENDED.

Magnet Installation

Depth

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EFI SYSTEM

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 breather cover 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.

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.

Earlier engines have a separate intake air temperature (IAT) sensor (located in throttle body) and a manifold absolute pressure (MAP) sensor (located in intake manifold).

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.

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.

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.

Later engines have a combined temperature/ manifold absolute pressure (TMAP) sensor (located in intake manifold).

Temperature/Manifold Absolute Pressure (TMAP) Sensor

A sealed non-serviceable integrated sensor that checks both intake air temperature and manifold absolute pressure. Complete replacement is required if it is faulty. Sensor and wiring harness can be checked as follows.

If a blink code indicates a problem with Intake Air Temperature (TMAP) Sensor Circuit (P0112 or P0113), it can be tested as follows:

1. Remove TMAP sensor from intake manifold.

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 1850-2450 Ω.

5. Unplug sensor from wire harness and check sensor resistance separately across pin. Resistance value should again be 1850-2450 Ω.

a. If resistance is out of speciﬁ cations, check local

temperature. Sensor resistance will go down as temperature is higher. Replace TMAP sensor if determined to be faulty.

b. If it is within speciﬁ cations, proceed to Step 6.

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EFI SYSTEM

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 #3 in sensor plug. Continuity should be indicated. Repeat test between Black pin 10 and terminal #4 in sensor plug.

7. Reinstall sensor.

If a blink code indicates a problem with Manifold Absolute Pressure (TMAP) Sensor Circuit (P0107 or P0108), it can be tested as follows:

1. Make sure all connections are making proper contact and are free of dirt and debris. Slide locking tab out and pull oﬀ TMAP 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.

3. Check to make sure intake manifold is not loose and TMAP sensor is not loose. Loose parts would allow a vacuum leak, making TMAP 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 sensor again. If MIL ﬁ nds a

fault with TMAP sensor, replace it.

Oxygen Sensor (O2)

Detail

Pin A

Pin D

Pin B

Pin C

Cutaway Oxygen Sensor Components (02)

A Protection Shield B

C Lower Insulator D

E Upper Insulator F

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 eﬀ ective 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.

High Temp

Water Seal

Planar Element

and Heater

Stainless Steel

Housing

Terminal Connection

to Element

Pin A

Pin C

Installation Torque 50.1 N·m (37 ft. lb.)

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Purple Wire,

Heater +

Black Wire, Sensor

Output

22 mm or 7/8 in.

Wrench Size

Pin B

Pin D

White Wire,

Heater -

Grey Wire, Sensor

Ground

18 mm x 1.5 Thread Size

Page 38

EFI SYSTEM

Visual Inspection Sensor Wire Detail

Keep a minimum of 25 mm (1.0 in.) radius at

grommet.

NOTE: Always route harness away from hot exhaust

and away from moving parts.

NOTE: Do not attempt to clean sensor. Replace as

needed.

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.

6. Inspect for any exhaust system leaks upstream or downstream of oxygen sensor. Conﬁ rm oxygen sensor is secured to 50.1 N·m (37 ft. lb.).

All leaks must be repaired and an ECU/TPS reset must be performed before proceeding with sensor testing.

7. Using diagnostic software, document any trouble codes. Determine if historic trouble codes are logically related to current fault experienced. If uncertain, clear codes and retest.

Sensor Signal Observation Engine Harness O2 Sensor Connector Plug Detail

A Red w/Black Stripe B Dark Green

C Purple D Black

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. With sensor connected and using diagnostic software, start engine to observe O2 sensor activity. Run engine at suﬃ cient speed to bring sensor and engine up to operating temperature (engine temperature of 150°F (66°C) or more displayed by diagnostic software).

Maintained throttle openings of less than 20% typically display closed loop operation where sensor output voltage should cycle between 0.05 to 0.95 Volts.

Maintained throttle openings of 30-40% and above typically display open loop operation where sensor should have above 0.500 Volt. Occasional spikes outside these values is normal. Lack of continuous ﬂ uctuation is not an indication of a defective sensor.

2. With key ON and engine OFF, sensor connected, using diagnostic software, O2 volts displayed should be more than 1.0 volt. This voltage is generated by ECU. If not present, there may be a power and/or ground supply fault to engine harness or ECU, a fault of engine harness itself (refer to Visual Inspection), or a fault of ECU.

With key ON and sensor unplugged, using a digital voltmeter, observe voltage between Pin socket C and Pin socket D of engine wiring harness (refer to engine harness connector plug detail at top of page). Voltage should read approximately 5.0 volts.

3. Using a digital voltmeter, observe system sensor voltage between Pin socket A and negative (-) battery ground. Battery voltage should be seen. If battery voltage is not seen, inspect engine wiring, fuses, and/or electrical connections.

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EFI SYSTEM

Removal Inspection NOTE: Apply anti-seize compound only to threads. Anti-seize compound will aﬀ ect 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. 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.

4. If a damaged sensor is found, identify root cause, which may be elsewhere in application. Refer to Troubleshooting-Oxygen (O2) Sensor table.

5. 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. Torque sensor to 50.1 N·m (37 ft. lb.).

Troubleshooting-Oxygen (O2) Sensor

Condition Possible Cause Conclusion

Continuous low voltage output (less than 400mV) observed with throttle openings of 30-40% or more.

Fault codes P0131, P0171, or P0174 may set.

Shorted sensor or sensor circuit. Shorted lead wire. Wiring shorted to ground.

Upstream or downstream exhaust leaks observed.

Air leak at sensor. Restricted fuel supply. Resolve fuel supply issues from tank

Misﬁ re A misﬁ re causing incomplete

Sensor failure-stuck lean. Replace sensor.

Replace sensor or replace and properly route wiring.

Repair all exhaust leaks and torque sensor to 50.1 N·m (37 ft. lb.).

to engine. Test fuel pressure. Perform repairs necessary.

combustion will result in lean (low voltage) values.

Continuous high voltage output (600mV or more) observed with throttle openings of 20% or less.

Fault codes P0172 or P0132 may set.

No activity from sensor.

Diagnostic software displays

1.015 Volts continuously.

Fault codes P0031 or P0032 may set.

Silica poisoning. Replace sensor. Identify and resolve

root cause. Contaminated gasoline. Purge fuel system and retest. Wiring shorted to voltage. Replace damaged harness. Overly rich condition due to

unmetered fuel entering combustion chamber.

Cold engine. Engine temperature below 150°F (66°C) as displayed by diagnostic software.

Sensor failure-stuck rich. Replace sensor. Heater circuit open or shorted. Replace sensor. Engine keyed ON with sensor

disconnected. Historic codes.

Contaminated gasoline. Purge fuel system and retest. Broken wire.

Damaged sensor.

Test fuel pressure. Inspect fuel pump

vent and evaporative emissions

hoses for raw fuel ﬂ ow.

Inspect engine oil for fuel

contamination; drain and reﬁ ll if

suspect.

Perform repairs as necessary.

Normal operation, or engine operated

in an excessively cold environment.

Secure and/or conﬁ rm sensor

connection and clear codes.

Replace sensor.

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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.

Details

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.

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

11.3 N·m (100 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.

Fuel Pump Module (FPM)

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.

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.

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EFI SYSTEM

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 intake manifold. 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

(7)

Three second pause

(6)

One second pause

(1)

(0)

End Code 61

Fault Code 0107

Diagnostic Fault Code Summary

Fault Code Connection or Failure Description

0031 Oxygen Sensor Heater Circuit Low Voltage 0032 Oxygen Sensor Heater Circuit High Voltage 0107 Manifold Absolute Pressure (MAP or TMAP) Sensor Circuit Low Voltage or Open 0108 Manifold Absolute Pressure (MAP or TMAP) Sensor Circuit High Voltage 0112 Intake Air Temperature (IAT or TMAP) Sensor Circuit Low Voltage 0113 Intake Air Temperature (IAT or TMAP) 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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Page 45

Fault Code Connection or Failure Description

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

EFI SYSTEM

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.

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

NOTE: Codes 0031 and 0032 may have been

mistakenly activated by turning key ON with oxygen sensor disconnected. If either code status is historic, that code may have set during assembly or a previous repair and may not be related to current event. Clear codes and retest to conﬁ rm. If code status is current, refer to Oxygen Sensor (O2) earlier in this section, to test and troubleshoot.

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 0032

NOTE: Codes 0031 and 0032 may have been

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

ECU Related

● ECU-to-harness connection problem.

Code 0107

Component: Manifold Absolute Pressure (MAP or

TMAP) Sensor

Fault: MAP or TMAP Circuit Low Voltage or

Open

Condition: Intake manifold leak, open connection or

faulty sensor.

Conclusion: MAP or TMAP 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 (MAP or

TMAP) Sensor Fault: MAP or TMAP Circuit High Voltage Condition: Intake manifold leak, shorted connection

or faulty sensor. Conclusion: MAP or TMAP 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 (IAT or TMAP)

Sensor

Fault: Intake Air Temperature (IAT or TMAP)

Sensor Circuit Low Voltage

Condition: Shorted connection, faulty sensor or

shorted wire.

Conclusion: Temperature (IAT or TMAP) Sensor

● 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 (IAT or TMAP)

Sensor

Fault: Intake Air Temperature (IAT or TMAP)

Sensor Circuit High Voltage or Open

Condition: Shorted connection, faulty sensor, broken

wire or connection.

Conclusion: Temperature (IAT or TMAP) Sensor

● 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.

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EFI SYSTEM

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.

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 aﬀ ected or disrupted by

dirt, grease, oil, wear.

● Sensor loose on throttle body manifold.

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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.

Page 48

EFI SYSTEM

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

● Diﬀ erence in voltage between sensed voltage and actual sensor voltage.

● Short in wire harness.

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

● Diﬀ erence 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 (muﬄ er, ﬂ ange,

oxygen sensor mounting boss, etc.).

● Fuel in crankcase oil.

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Page 49

EFI SYSTEM

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

● Diﬀ erence 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 ﬁ lled.

● Lift pump diaphragm is ruptured.

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 ﬁ 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.

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Engine Wiring Harness Related

● Broken or shorted wire in harness.

ECU pin Black 5.

● Wiring from Ignition.

ECU Related

● Circuit controlling injector #1 damaged.

Page 50

EFI SYSTEM

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 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

NOTE: If fault code P0337 is present and engine does

not start/run, proceed to step 1 of Crankshaft Position Sensor earlier in this section. If P0337 is present and engine operates, clear codes and retest.

Code 0232

Component: Fuel Pump Fault: Circuit High Voltage Condition: Shorted connection. Conclusion: Fuel Pump Related

● Fuel pump module damaged internally.

Charging Output System Too High.

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

● A false fault code P0337 is triggered by a voltage drop with key ON and engine oﬀ . Voltage drop may be caused by a poor/inadequate battery connection, battery charger connected or disconnected, or any event that may interrupt voltage signal to ECU like a power interruption or heavy load from equipment that results in a recordable voltage drop.

● 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.

If code is stored in fault history and starts normally. Clear code, no other service required.

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Page 51

EFI SYSTEM

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.

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.

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

Troubleshooting Flow Chart

Flow 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.

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 ﬂ 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.

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Page 52

EFI SYSTEM

EFI Diagnostic Flow Diagram

START OF TEST

KEY ON

PROCEED TO START OF TEST FOR RETEST

MALFUNCTION

INDICATOR LIGHT

ARE FAULT CODES

PRESENT?

DOES ENGINE START?

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

YES MIL GOES OFF?

YES

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?

END OF TEST

FUEL PUMP

REFER TO DIAGNOSTIC

YES

FAULT CODE SUMMARY

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?

YES

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

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.

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Page 53

EFI 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 ﬁ 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 ﬁ lter plugged

● Fuel supply line plugged

● Lift fuel pump - insuﬃ cient fuel supply

● Fuel pump (lift or module) - internally plugged

● 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.

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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Page 54

Governor System

GOVERNOR

These engines are equipped with an electronic governor or a mechanical governor.

ELECTRONIC GOVERNOR

Electronic Governor System Designs

As of this revision, there is an original design, a ﬁ eld installed updated design, and a new updated design. All designs function in same manner, and both updated designs have a non-serviceable electrical connection with a sealed (bonded) GCU module wiring harness assembly.

Electronic Governor System

Electronic governor regulates engine speed at varying loads based on a variable input voltage from application (potentiometer or a single pole, single throw (SPST) switch).

Typical electronic governor includes:

● Digital linear actuator (DLA).

● Throttle linkage.

● Linkage spring.

● Linkage retaining clip.

● Governor control unit (GCU).

Components

NOTE: Actual speeds depend on application. Refer to

equipment manufacturer’s recommendations.

Potentiometer Speciﬁ cations

Speed Input Voltage Engine Speed (RPM)

0-1 Low Speed Endpoint

1-9 Variable Speed Endpoint

9-16 High Speed Endpoint

DLA Function

DLA function can be tested and conﬁ rmed using a stepper motor controller tool. Refer to Tools and Aids. Testing instructions are included with this tool.

Throttle 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. Detailed instructions are in steps 4 and 5.

Adjustment DLA Details

A DLA B

C Throttle Linkage D Linkage Spring

Throttle Body Lever

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.

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.

Adapter

F Throttle Body

Plastic Linkage

Retaining Clip

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.).

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Page 55

Governor System

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.

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 ﬂ 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.

7. Loosen DLA bracket screws slightly, to allow

adjustment. Slide DLA bracket assembly back (away from engine) until throttle plate is fully open. Hand tighten screws to maintain this position.

Operation of Electronic Governor System

1. Key is turned ON, providing power to GCU (red lead from engine harness to GCU harness).

2. Engine is cranked, GCU receives speed input/tach signal from ECU (grey lead from engine harness to white lead in GCU harness).

3. GCU commands DLA to close (home) then open a preprogramed amount, typically 10-15%.

4. GCU identiﬁ es engine is running by speed input/tach signal.

5. GCU identiﬁ es speed input voltage (red w/yellow tracer from OEM harness to GCU harness) and commands DLA to control throttle as required to maintain selected speed.

A Equal Distance

B Full Throttle Position

8. Measure distance from face of DLA bracket and top of E-Gov bracket edge as shown above. Adjust DLA bracket until measurement is same distance (within

0.5 mm/0.020 in.), while adjusting to full open throttle plate as described in step 7. Once this position is established, hold in this position and torque DLA bracket screws to 10.2 N·m (90 in. lb.).

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Page 56

Governor System

Electronic Governor System Designs

Identify design on engine being serviced and follow those pages to diagnose and troubleshoot.

Original Design

Field Installed Updated Design

Non-Serviceable Electrical Connection.

This Governor Control Unit has a

DO NOT SEPARATE

A Original Design B

Digital Linear Actuator

(DLA)

Governor Control Unit

(GCU)

2 DLA Throttle Plate

Mounting Screws

E Wiring Harness F Speed Control Input

Original Design features a GCU and wiring harness

that can be separated and tested for power and ground. This design is easily identiﬁ ed by 2 screws that secure DLA actuator bracket. See pages 58-64 for an engine with original design electronic governor.

Sealed (Bonded) GCU

Field Installed

Updated Design

Module Wiring

Harness

Assembly

I Sealed GCU Label J

3 DLA Throttle Plate

Mounting Screws

GCU Wire Tie-Down

Bracket

L Speed Control Input

Field Installed Updated Design features a sealed

(bonded) GCU module wiring harness assembly that must NOT be separated. This design is easily identiﬁ ed by 3 screws that secure DLA actuator bracket. This design also has GCU wire tie-down bracket and single Speed Control Input wire. See pages 65-71 for an engine with ﬁ eld installed updated design electronic governor.

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Page 57

New Updated Design

Governor System

Non-Serviceable Electrical Connection.

This Governor Control Unit has a

DO NOT SEPARATE

Non-Serviceable Electrical Connection.

This Governor Control Unit has a

DO NOT SEPARATE

New Sealed (Bonded)

M New Updated Design N

GCU Module

Wiring Harness

Assembly

4 Pin GCU to Main

Engine Harness

P Speed Control Input

New Updated Design features a sealed (bonded) GCU

module wiring harness assembly that must NOT be separated. This design is easily identiﬁ ed by 3 screws that secure DLA actuator bracket. This design also has GCU wire tie-down bracket, plus a 4 pin connector with speed input wire red w/yellow tracer. See pages 72-78 for an engine with new updated design electronic governor.

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Page 58

Governor System

ORIGINAL DESIGN 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.

Original design features a separate GCU and wiring harness that can be separated and tested for power and ground. This design is easily identiﬁ ed by 2 screws that secure DLA actuator bracket. See page 56 for an engine with original design electronic governor.

ORIGINAL DESIGN 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.

Test 1 Probe Location (Original Design)

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.

Test 2 Probe Location (Original Design)

ORIGINAL DESIGN 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 1 Probe Location (Original Design)

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.

Test 2 Probe Location (Original Design)

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.

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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.

Page 59

Governor System

ORIGINAL DESIGN Speed Control Input

A Red Wire with Yellow Tracer.

This connection is a single wire red with yellow tracer.

ORIGINAL DESIGN GCU Blink Code Tests

A Green LED Light B Yellow LED Light

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.

ORIGINAL DESIGN GCU Blink Codes for Software Stored Codes - Activated when key is turned to ON

position.

Response

Failure Condition Possible Causes Response

Speed Error BLINKS ON

Watchdog Interrupt RFI interference Ground to kill,

close throttle plate

Ground to kill, close throttle plate

Overspeed (Over 4500 RPM for 0.5 seconds sustained)

Excessive Battery Voltage (> 18v for

0.5 seconds)

Overtemp

Software bug

Lightning

External noise on ECU input Ground to kill,

Frozen throttle plate

DLA failure

Mechanical bindage

Overcharging electrical system >18 volts

Time

1 second delay

0.5 seconds

LED Diagnostics

Yellow LED Green LED

BLINKS BLINKS

ON ON

OFF ON

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Page 60

Governor System

ORIGINAL DESIGN 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)

Speed Out of Range-Low

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

Overcharging electrical system >18 volts

Pin corrosion/fretting at GCU OFF BLINKS

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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Governor System

ORIGINAL DESIGN Troubleshooting Electronic Governor

Failure Condition Possible Causes Equipment Observations Inspection/Testing

Target/Selected Speed not Maintained (Overspeed and/or Underspeed) (No hunt or surge)

Target/Selected Speed Not Maintained (Over speed and/or Under speed) (No hunt or surge)

No Start and/or ungoverned speed below 1500 RPM

No response to selected speed input

Rapid hunting and/or surging

Loss of GCU power (B+ or Ground). (Potentially Intermittent)

Loss of ECU Speed Output (Speed Signal) (Potentially Intermittent)

Throttle fully closed. No throttle movement.

Loss of application supplied speed control input signal.

Rev-limiting feature active. (ECU controlled limitation)

When connection is lost, no DLA movement will be seen. When connection is restored, GCU will command DLA to perform homing sequence. Throttle closes then returns to target speed position.

When connection is lost, no DLA movement will be seen. When connection is restored, throttle returns to target speed position.

While cranking, GCU commands DLA to open to a predetermined position. If no movement is seen, engine may not start due to closed throttle. If engine starts, engine speed will be below 1500 RPM.

GCU regulates engine speed by variable input voltage from a customersupplied source. When signal is lost, engine speed will return to idle. When connection is restored, throttle returns to target speed position.

If maximum RPM limit (4500 RPM +) is exceeded, ECU suppresses injection signals, cutting oﬀ fuel ﬂ ow. This process repeats itself in rapid succession, limiting operation to preset maximum.

Test GCU power (red/B+) wire for supply voltage and test ground circuit. Inspect all connections and wires for poor connection. Repair and replace as required.

View GCU blink codes for potential trouble code. Inspect all connections and wires for poor connection. Repair and replace as required.

Using EFI Diagnostic Software, observe TPS value for movement, check system power, physical binding, and wiring etc.

Conduct speed input wire (red w/yellow tracer) voltage test. (Refer to test description on page 63 for more information)

See rows 1 and 2, view throttle position, observe for movement. Test DLA function using stepper motor controller tool. Refer to Tools and Aids.

6162 690 05 Rev. E KohlerEngines.com

Page 62

Governor System

ORIGINAL DESIGN 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 54.

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 54 and 55.

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 54). 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

Test control system of equipment. Refer to Equipment

Go to 12 Volt Power Test on next page.

62 62 690 05 Rev. EKohlerEngines.com

Manufacturer’s diagnostic procedures for control system.

Page 63

ORIGINAL DESIGN Electronic Governor Troubleshooting Flow Chart Continued

Governor System

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).

Locate Speed Control input wire. This connection is a single wire red with yellow tracer. See illustration on page 59.

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.

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.

Review GCU blink codes with chart on page 60 to identify if a system condition is present.

Proceed to Ground/Power and OHMs test for GCU. Refer to page 58.

Remove GCU and unplug wiring harness. See illustration on page 56.

GCU Circuit Test.

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 58.

Continued on next page

6362 690 05 Rev. E KohlerEngines.com

Page 64

Governor System

ORIGINAL DESIGN Electronic Governor Troubleshooting Flow Chart Continued

Turn key switch to ON position. Test supply voltage to GCU using volt meter. Refer to page 58 (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 58.

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 58.

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+

Power

Device Ground

Speed Signal

Green LED Light

Yellow LED Light

DLA Driver Controls

1 2 6 7

ECU Speed Output (speed signal)

ECU

Application Supplied Speed Control Input

Operation Input Voltage: 0-1 Volts at Idle/9+ Volts at High Speed

64 62 690 05 Rev. EKohlerEngines.com

DLA

Page 65

FIELD INSTALLED UPDATED DESIGN GCU/Harness Diagnostics and Troubleshooting

This updated design was ﬁ rst released as a ﬁ eld installed kit with a sealed GCU/wiring harness module assembly and separate red wire w/yellow tracer speed control input.

Ground and Power Test

NOTE: This updated design features a sealed GCU

module wiring harness assembly that is serviced as an assembly and must NOT be separated.

1. Remove 2 screws securing sealed GCU wiring harness assembly to GCU bracket.

2. Turn ignition key to ON position, inspect LED lights on GCU board, should indicate solid green and blinking yellow. If no LED illumination, inspect all system fuses (10 amp power fuses). If fuses are OK, proceed to following power/probe test. Turn ignition key to OFF position.

Governor System

FIELD INSTALLED UPDATED DESIGN GCU Power Test/Probe Location

A Negative (-) Ground Probe Location

C Red Power (B+) Probe Location

3. Connect DVOM black/ground test lead to ground eyelet terminal (A).

4. Cut nylon tie (B) to gain access to bullet connector under protective sleeve.

5. Use Red (B+) DVOM test lead and probe red power (B+) wire connector (C).

Using a DVOM 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. If no power is measured, inspect all system fuses (10 amp power fuses). If not within +/- 1 volt of battery voltage, check connections and replace GCU module wiring harness assembly if necessary.

FIELD INSTALLED UPDATED DESIGN Speed Control Input

B Cut Wire Tie to Access Spade or Butt Connector

A Red Wire with Yellow Tracer.

This connection is a single wire red with yellow tracer.

6562 690 05 Rev. E KohlerEngines.com

Page 66

Governor System

FIELD INSTALLED UPDATED DESIGN GCU Blink Code Tests

A Green LED Light B Yellow LED Light

FIELD INSTALLED UPDATED DESIGN GCU Blink Codes for Software Stored Codes - Activated when key is turned to ON position.

Response

Failure Condition Possible Causes Response

Speed Error BLINKS ON

Watchdog Interrupt RFI interference Ground to kill,

close throttle plate

Ground to kill, close throttle plate

Overspeed (Over 4500 RPM for 0.5 seconds sustained)

Excessive Battery Voltage (> 18v for

0.5 seconds)

Overtemp

Software bug

Lightning

External noise on ECU input Ground to kill,

Frozen throttle plate

DLA failure

Mechanical bindage

Overcharging electrical system >18 volts

Time

1 second delay

0.5 seconds

LED Diagnostics

Yellow LED Green LED

BLINKS BLINKS

ON ON

OFF ON

66 62 690 05 Rev. EKohlerEngines.com

Page 67

Governor System

FIELD INSTALLED UPDATED DESIGN 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)

Speed Out of Range-Low

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

Overcharging electrical system >18 volts

Intermittent/open connection at GCU

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

OFF BLINKS

6762 690 05 Rev. E KohlerEngines.com

Page 68

Governor System

FIELD INSTALLED UPDATED DESIGN Troubleshooting Electronic Governor

Failure Condition Possible Causes Equipment Observations Inspection/Testing

Target/Selected Speed not Maintained (Overspeed and/or Underspeed) (No hunt or surge)

Target/Selected Speed Not Maintained (Over speed and/or Under speed) (No hunt or surge)

No Start and/or ungoverned speed below 1500 RPM

No response to selected speed input

Rapid hunting and/or surging

Loss of GCU power (B+ or Ground). (Potentially Intermittent)

Loss of ECU Speed Output (Speed Signal) (Potentially Intermittent)

Throttle fully closed. No throttle movement.

Loss of application supplied speed control input signal.

Rev-limiting feature active. (ECU controlled limitation)

When connection is lost, no DLA movement will be seen. When connection is restored, GCU will command DLA to perform homing sequence. Throttle closes then returns to target speed position.

When connection is lost, no DLA movement will be seen. When connection is restored, throttle returns to target speed position.

While cranking, GCU commands DLA to open to a predetermined position. If no movement is seen, engine may not start due to closed throttle. If engine starts, engine speed will be below 1500 RPM.

If maximum RPM limit (4500 RPM +) is exceeded, ECU suppresses injection signals, cutting oﬀ fuel ﬂ ow. This process repeats itself in rapid succession, limiting operation to preset maximum.

Test GCU power (red/B+) wire for supply voltage and test ground circuit. Inspect all connections and wires for poor connection. Repair and replace as required.

View GCU blink codes for potential trouble code. Inspect all connections and wires for poor connection. Repair and replace as required.

Using EFI Diagnostic Software, observe TPS value for movement, check system power, physical binding, and wiring etc.

Conduct speed input wire (red w/yellow tracer) voltage test. (Refer to test description on page 70 for more information)

See rows 1 and 2, view throttle position, observe for movement. Test DLA function using stepper motor controller tool. Refer to Tools and Aids.

68 62 690 05 Rev. EKohlerEngines.com

Page 69

Governor System

FIELD INSTALLED UPDATED DESIGN 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 54.

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 54 and 55.

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

Pass

Go to 12 Volt Power Test on next page.

Test control system of equipment. Refer to Equipment Manufacturer’s diagnostic procedures for control system.

6962 690 05 Rev. E KohlerEngines.com

Page 70

Governor System

FIELD INSTALLED UPDATED DESIGN Electronic Governor Troubleshooting Flow Chart Continued

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 65.

Attach open end of jumper wire to positive (+) battery terminal. See illustration on page 65.

Locate Speed Control input wire. This connection is a single wire red with yellow tracer. See illustration on page 65.

Unplug and connect a jumper wire to red wire with a yellow tracer on engine wire harness.

See illustration on page 65.

Engine speed increases (if it was at low speed).

Fail

Engine speed does not change.

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.

Review GCU blink codes with chart on page 67 to identify if a system condition is present.

Proceed to Ground/Power test for GCU. Refer to page 65.

Inspect wiring harness for broken wire or bad connections. Repair/Replace as required.

Test ground circuit to GCU. Refer to page 65.

Continued on next page

70 62 690 05 Rev. EKohlerEngines.com

Page 71

Governor System

FIELD INSTALLED UPDATED DESIGN Electronic Governor Troubleshooting Flow Chart Continued

Turn key switch to ON position. Test supply voltage to GCU using volt meter. Refer to page 65. (Battery voltage +/- 1 volt)

DLA function can be tested and conﬁ rmed using a stepper motor controller tool. Refer to Tools and Aids. Testing instructions are included with tool.

If test fails, DLA is no good and should be replaced. If DLA test is good, another component, connection, or input is most likely at fault.

Basic Electrical Diagram of Electronic Governor System

B+

Power

Device Ground

Application Supplied Speed Control Input

Speed Signal

Green LED Light

Yellow LED Light

DLA Driver Controls

1 2 6 7

ECU Speed Output (speed signal)

ECU

DLA

Operation Input Voltage: 0-1 Volts at Idle/9+ Volts at High Speed

7162 690 05 Rev. E KohlerEngines.com

Page 72

Governor System

NEW UPDATED DESIGN GCU/Harness Diagnostics and Troubleshooting

A new updated design has been released with a sealed GCU/wiring harness module assembly, that features a four pin connector instead of spade or butt connectors.

Ground and Power Test

NOTE: This updated design features a sealed GCU

module wiring harness assembly that is serviced as an assembly and must NOT be separated.

1. Remove 2 screws securing sealed GCU wiring harness assembly to GCU bracket.

NEW UPDATED DESIGN GCU Power Test/Probe Location

E-Gov Jumper Test

C White D Red (+)

E Application F

Red w/Yellow Tracer

Tool

(Speed Input)

B Black (Ground -)

Dark Blue

(Application

Speed Input)

H Engine

6. With tool installed, start engine. Connect a jumper wire (technician supplied) to red w/yellow tracer bullet of tool. Connect other end of jumper wire to battery 12 volt +. Engine speed should increase. Remove jumper from red w/yellow tracer bullet of tool and speed should return to low speed (idle).

7. If speed did increase, refer to equipment manufacturer’s manual for application speed input voltage from their controller. (Dark blue wire bullet of test tool can be used for measuring this input signal voltage with a DVOM.) If speed did not increase in test above, perform continuity test below on red w/ yellow tracer (speed input).

New Updated Design Speed Control Input

4 pin connector main engine wiring harness to

In New Updated Design system, Speed Control Input wire (red w/yellow tracer) is located in terminal location B of 4 pin connector. Using a DVOM, perform continuity test from pin location B of 4 pin connector to pin location G of 8 pin customer connector. Continuity should be seen.

If no continuity, repair/replace main engine wiring harness.

If continuity is seen, refer to equipment manufacturer’s manual.

8 pin customer connector main engine wiring

GCU wiring harness

harness

3. Install E-Gov Jumper Test Tool (refer to Tools and Aids) between 4 pin GCU connectors. (Ensure wiring is retained and away from any hot surfaces.)

4. Using a DVOM set to DC volts, test system for voltage to GCU. Red meter lead (+) to red wire bullet of test tool and Black meter lead (-) to black wire bullet of test tool. Battery voltage should be seen with key ON. If no voltage is seen, inspect 10 Amp system fuse.

5. Relocate black (-) negative DVOM lead to battery ground. If no voltage is seen, inspect and repair main engine wiring harness. If battery voltage is seen after relocating meter lead, ground circuit in harness is open. Trace black ground wire to ground mounting boss under blower housing and inspect/ repair as needed.

72 62 690 05 Rev. EKohlerEngines.com

Page 73

Governor System

NEW UPDATED DESIGN GCU Blink Code Tests

A Green LED Light B Yellow LED Light

NEW UPDATED DESIGN 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)

Overtemp

Software bug

Lightning

External noise on ECU input Ground to kill,

Frozen throttle plate

DLA failure

Mechanical bindage

Overcharging electrical system >18 volts

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

7362 690 05 Rev. E KohlerEngines.com

Page 74

Governor System

NEW UPDATED DESIGN 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)

Speed Out of Range-Low

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

Overcharging electrical system >18 volts

Intermittent/open connection at GCU

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

OFF BLINKS

74 62 690 05 Rev. EKohlerEngines.com

Page 75

Governor System

NEW INSTALLED UPDATED DESIGN Troubleshooting Electronic Governor

Failure Condition Possible Causes Equipment Observations Inspection/Testing

Target/Selected Speed not Maintained (Overspeed and/or Underspeed) (No hunt or surge)

Target/Selected Speed Not Maintained (Over speed and/or Under speed) (No hunt or surge)

No Start and/or ungoverned speed below 1500 RPM

No response to selected speed input

Rapid hunting and/or surging

Loss of GCU power (B+ or Ground). (Potentially Intermittent)

Loss of ECU Speed Output (Speed Signal) (Potentially Intermittent)

Throttle fully closed. No throttle movement.

Loss of application supplied speed control input signal.

Rev-limiting feature active. (ECU controlled limitation)

When connection is lost, no DLA movement will be seen. When connection is restored, GCU will command DLA to perform homing sequence. Throttle closes then returns to target speed position.

When connection is lost, no DLA movement will be seen. When connection is restored, throttle returns to target speed position.

While cranking, GCU commands DLA to open to a predetermined position. If no movement is seen, engine may not start due to closed throttle. If engine starts, engine speed will be below 1500 RPM.

If maximum RPM limit (4500 RPM +) is exceeded, ECU suppresses injection signals, cutting oﬀ fuel ﬂ ow. This process repeats itself in rapid succession, limiting operation to preset maximum.

Test GCU power (red/B+) wire for supply voltage and test ground circuit. Inspect all connections and wires for poor connection. Repair and replace as required.

View GCU blink codes for potential trouble code. Inspect all connections and wires for poor connection. Repair and replace as required.

Using EFI Diagnostic Software, observe TPS value for movement, check system power, physical binding, and wiring etc.

Conduct speed input wire (red w/yellow tracer) voltage test. (Refer to test description on page 77 for more information)

See rows 1 and 2, view throttle position, observe for movement. Test DLA function using stepper motor controller tool. Refer to Tools and Aids.

7562 690 05 Rev. E KohlerEngines.com

Page 76

Governor System

NEW UPDATED DESIGN 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 54.

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 54 and 55.

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

Pass

Test control system of equipment. Refer to Equipment

Go to 12 Volt Power Test on next page.

76 62 690 05 Rev. EKohlerEngines.com

Manufacturer’s diagnostic procedures for control system.

Page 77

NEW UPDATED DESIGN Electronic Governor Troubleshooting Flow Chart Continued

Governor System

12 Volt Power Test

On new updated design engines, E-Gov Jumper Test Tool (refer to Tools and Aids) is recommended to perform 12 volt power test.

Using a jumper wire, supply 12 volt (+) to red wire w/yellow tracer bullet connector on E-Gov Jumper Test Tool. Engine RPM should increase to high speed (approx. 3600 RPM).

Engine speed increases (if it was at low speed).

Fail

Engine speed does not change.

Review GCU blink codes with chart on page 74 to identify if a system condition is present.

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.

Proceed to Ground/Power test for GCU. Refer to page 72.

Inspect wiring harness for broken wire or bad connections. Repair/Replace as required.

Test ground circuit to GCU. Refer to page 72.

Turn key switch to ON position. Test supply voltage to GCU using volt meter. Refer to page 72. (Battery voltage +/- 1 volt)

DLA function can be tested and conﬁ rmed using a stepper motor controller tool. Refer to Tools and Aids. Testing instructions are included with tool.

If test fails, DLA is no good and should be replaced. If test is good, another component, connection, or input is most likely at fault.

7762 690 05 Rev. E KohlerEngines.com

Page 78

Governor System

Basic Electrical Diagram of Electronic Governor System

B+

Power

Device Ground

Application Supplied Speed Control Input

Speed Signal

Green LED Light

Yellow LED Light

DLA Driver Controls

1 2 6 7

ECU Speed Output (speed signal)

ECU

DLA

Operation Input Voltage: 0-1 Volts at Idle/9+ Volts at High Speed

78 62 690 05 Rev. EKohlerEngines.com

Page 79

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

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 ﬂ 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 oﬀ set each other to hold a steady engine speed.

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 clockwise (viewed from end) as far as it will turn, then torque nut to 7.1 N·m (63 in. lb.).

7962 690 05 Rev. E KohlerEngines.com

Page 80

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

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

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.

ﬁ lter.

installation.

indicator on dipstick.

leaks. Recheck oil level.

local ordinances.

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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.

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Electrical System

BATTERY CHARGING SYSTEM

CAUTION

Electrical Shock can cause injury. Do not touch wires while engine is running.

NOTE: Observe following guidelines to avoid damage to

electrical system and components:

● Make sure battery polarity is correct. A negative (-) ground system is used.

20/25 Amp Regulated Charging System

● Disconnect rectiﬁ 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.

A Battery B Starter C Fuse D Rectiﬁ 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

Rectiﬁ er-regulator is mounted on blower housing. To replace, disconnect plug(s), remove mounting screws, and ground wire or metal grounding strap.

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.

Flywheel Stator

Assembly

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.

Battery Test

To test battery, follow manufacturer's instructions.

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Electrical System

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. Inspect condition of fuse holder.

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.

6. If replacement fuse fails, there is a problem within circuit. Diagnostics are required. Identify which circuit is aﬀ ected (see EFI System for electrical schematic) by identifying failed fuse/circuit. Perform troubleshooting procedures appropriate for circuit fuse that failed.

7. Install fuse holder into fuse cover.

Troubleshooting Guide 20/25 Amp Battery Charging System

NOTE: Always zero digital volt-ohm meter (DVOM) on

each scale before testing to ensure accurate readings. Voltage test should be made with engine running at speciﬁ c test condition noted. Battery should be checked for state of charge (non-operating voltage 12.5 VDC or lower, battery should be charged or replaced).

When problems occur in keeping a battery fully charged or a battery charges at a high rate, battery or charging system may be cause of fault. Before performing any testing, battery must be fully charged.

To test charging system:

1. Visually inspect system components and wiring. Look for damaged or loose wire connections, including battery cables.

2. Set DVOM to DC volts, place one lead of tester on rectiﬁ er-regulator body and other lead to battery negative (-) terminal. Run engine and observe volt reading on meter. If voltage is 0.5 VDC or less continue with testing. If voltage is higher than 0.5 VDC, inspect and repair wiring/connections as needed (insuﬃ cient ground).

3. Perform these output tests for charging system using DVOM set to DC volts.

a. With engine oﬀ and key switch in OFF position,

measure voltage at battery. If less than 12.4 VDC, recharge battery and retest. If 12.5 VDC continue with tests.

10-amp Fuse

b. Run engine at high speed no load (greater than

3000 RPM). After running 1 minute, measure voltage at battery.

i. If voltage increases to between 13-15 VDC,

the system is working correctly.

ii. If voltage increases to 15.5 VDC or higher,

system is overcharging. Replace rectiﬁ erregulator.

iii. If voltage stays at 12.5 VDC or decreases,

charging system is NOT operating, proceed to step 4.

4. With engine oﬀ , unplug rectiﬁ er-regulator connector and inspect connector terminals within connector body and rectiﬁ er-regulator terminals for corrosion/ arching/damage. Repair/replace as needed. If OK, proceed to next test.

5. Set DVOM to AC volts, place test leads to each white stator wire. Run engine at 1200 RPM or greater and monitor voltage.

Condition Conclusion

Voltage is 13 volts AC or more.

Voltage is less than 13 volts AC.

6. With engine oﬀ and stator unplugged from rectiﬁ erregulator, check for resistance/continuity between across stator leads (white wires).

Condition Conclusion

Resistance is 0.1/0.2 ohms.

Resistance is 0 ohms. Stator is shorted; replace. Resistance is inﬁ nity

ohms/no continuity.

7. With engine oﬀ and stator unplugged from rectiﬁ erregulator, check for resistance/continuity from stator leads (white wires) to ground.

Condition Conclusion

Resistance is inﬁ nity ohms (no continuity).

Resistance (or continuity) measured.

8. If stator tests good (steps 4-7), but system was identiﬁ ed in step 3 as not working, failure is likely with rectiﬁ er-regulator. Replace rectiﬁ er-regulator, retest system to conﬁ rm repairs (step 3).

Stator is OK.

Stator is faulty. Continue with steps 6 and 7).

Stator coil is OK.

Stator is open; replace.

Stator is OK (not shorted to ground).

Stator leads are shorted to ground; replace.

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Electrical System

IGNITION SYSTEM Spark Plug Spark Plug Component and Details

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 (0.030 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.

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 fuel mixture.

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

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

Service

Clean out spark plug recess. Remove plug and replace.

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.).

A wet plug is caused by excess fuel or oil in combustion chamber. Excess fuel could be caused by a restricted air cleaner, a fuel mixture 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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Electrical System

Carbon Fouled

Soft, sooty, black deposits indicate incomplete combustion caused by a restricted air cleaner, over rich fuel mixture, weak ignition, or poor compression.

Troubleshooting Guide Test Ignition System

NOTE: If engine starts or runs during testing, you may need to ground kill lead to shut it down. Because you have

interrupted kill circuit, it may not stop using switch.

Isolate and verify trouble is within engine.

1. If Kohler diagnostic software is available, review "Safety System Active" status in Data Display screen. If yes is displayed, equipment safety circuit is active (seat switch/PTO switch/Safety interlocks, etc.). This must be corrected prior to continuing testing.

If diagnostic software is not available, locate connectors where wiring harnesses from engine and equipment are

joined. Separate connectors and remove white kill lead from engine connector. Rejoin connectors and position or insulate kill lead terminal so it cannot touch ground. Try to start engine to verify whether reported problem is still present.

Overheated

Chalky, white deposits indicate very high combustion temperatures. This condition is usually accompanied by excessive gap erosion. Lean fuel mixture settings, an intake air leak, or incorrect spark timing are normal causes for high combustion temperatures.

Condition Possible Cause Conclusion

Problem goes away. Electrical System Check key switch, wires,

connections, safety interlocks, etc.

Problem persists. Ignition or Electrical System Leave kill lead isolated until all

testing is completed. Identify white kill lead of engine

wiring harness connector. Establish a connection to a known good ground location. Engine should kill completely. If not or only 1 cylinder is aﬀ ected, test ignition coils.

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Electrical System

Test for Spark

NOTE: If 2 ignition system testers are available, testing can be performed simultaneously for both cylinders. However,

if only 1 tester is available, 2 individual tests must be performed. Side not being tested must have spark plug lead connected or grounded. Do not crank engine or perform tests with 1 spark plug lead disconnected and not grounded, or permanent coil damage may occur.

1. With engine stopped, disconnect 1 spark plug lead. Connect spark plug lead to post terminal of spark tester and attach tester clip to a good engine ground.

2. Crank engine over, establishing a minimum of 350-450 RPM, and observe tester(s) for spark.

3. Repeat spark test on opposite cylinder if cylinders are being tested individually.

Condition Possible Cause Conclusion

1 cylinder is not ﬁ ring or 1 cylinder has good spark and other cylinder has no or intermittent spark.

Tester shows spark but engine misses or won’t run on that cylinder.

Neither side is ﬁ ring. Ignition Switch, EFI

Both cylinders have good spark but engine runs poorly or existing plug condition is questionable.

Wiring, Connections, or

System Power

Spark Plug(s) Try new spark plug(s).

Flywheel Key Remove ﬂ ywheel, inspect key, replace key if damaged.

System, Kill Lead

Spark Plug(s) Install new spark plug(s) and retest engine

Flywheel Key Remove ﬂ ywheel, inspect key, replace key if damaged.

Using a DVOM, attach black (-) lead of meter to battery ground, remove primary plug from coil, test voltage at red wire with black tracer at coil primary connector with ignition key ON. Battery voltage should be seen. If no voltage, check all fuses. Key OFF, perform continuity test between black primary wire connector and corresponding terminal connector (ignition coil #1 or #2) on black or grey ECU connector (see EFI System Wiring Diagram). If no continuity is found, repair or replace electrical wiring harness. If continuity is found, refer to EFI System, Ignition Coil Testing or exchange ignition coils (side to side) and retest. If problem follows ignition coil, replace that coil. If problem stays with cylinder, test circuit (power and ground) for problem cylinder. Repair/replace as needed. Test ignition coils and connections. Refer to Test Ignition System (on previous page).

Test for "Safety System Active" as described in step 1 of Test Ignition System (on previous page). Inspect red 10 amp fuses. Replace fuse if found blown. If fuse is OK, using a DVOM, attach black (-) lead of meter to battery ground, key ON, test for voltage at 2 red 10 amp fuses. Battery voltage should be seen on both sides of fuses. If voltage is found on 1 side of fuse only, inspect for blown fuse or inspect fuse holder/ terminals for arching or corrosion. If no voltage is seen at any fuse, further electrical testing inspection is required (application, key switch, ground connections, etc.). Recheck position of ignition switch and check for shorted kill lead.

performance.

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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

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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Starter System

SOLENOID SHIFT STARTERS

When power is applied to starter electric solenoid moves drive pinion out onto drive shaft and into mesh with ﬂ 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

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

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

U Bolt

88 62 690 05 Rev. EKohlerEngines.com

Plate

Screw

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.

Page 89

Starter System

Armature Components and Details

A Commutator O.D. B Mica Insulation

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 diﬀ erent 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 oﬀ set thrust (stop) washer so smaller oﬀ set 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

ﬂ 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.

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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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Page 91

WARNING

Accidental Starts can cause severe injury or death.

Disconnect and ground spark plug lead(s) before servicing.

External Engine Components

Disassembly/Inspection and Service

Before working on engine or equipment, disable engine as follows: 1) Disconnect spark plug lead(s). 2) Disconnect negative (–) battery cable from battery.

A Dipstick B Oil Drain Plug C Oil Fill Tube D Valley Baﬄ e

E Spark Plug Lead F Barrel Baﬄ e G Starter Assembly H Ignition Coil

Fuel Pump Module

M Electrical Connector N Evap Line O

Q Oil Filter R

Baﬄ e

J Fuel Filter K Fuel Pump Module L Fuel Pump

High Pressure Fuel

Line Connector

Blower Housing with

Fixed Guard

S Cylinder Shroud T

P Oil Cooler

Fan/Flywheel

Assembly

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Page 92

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

NOTE: Unless oxygen sensor is damaged or

malfunctioning, disassembly from muﬄ er is unnecessary.

Remove exhaust system and attaching hardware from engine. On engines equipped with a port liner, remove it now.

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 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.

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 111.

Do not cut any Oetiker clamps unless fuel lines and/

or fuel ﬁ lter are being replaced.

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

Special Washer

(Style A)

Debris Screen

(Style A)

Flywheel/Fan/Hex

E Washer F

Stud Assembly

(Style A)

I Stator J

Rectiﬁ er-Regulator

Connector

M Breather Hose N Oil Sentry

Debris Screen

(Style B)

Support Ring

(Style B)

Backing Shroud/

Intake Manifold/

MAP or TMAP

Sensor Connector

Oil Temperature

Stiﬀ ener

(Style A)

Air Cleaner

Sensor

Spacer

(Style B)

D Flywheel Screw

Crankshaft Position

Sensor

L Ground Lead

P Reducer Bushing

Flywheel/Fan/Hex

Stud Assembly

(Style B)

9362 690 05 Rev. E KohlerEngines.com

Page 94

Disassembly/Inspection and Service

Remove Crankshaft Position Sensor

1. Remove two bracket mounting screws and crankshaft position sensor from backing shroud. Keep leads in place and let bracket and crankshaft position 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 (Style A)

Remove screws and special washers securing debris screen to studs in ﬂ ywheel; then remove stiﬀ ener. Hex studs and cooling fan can stay attached to ﬂ ywheel.

Remove Debris Screen (Style B)

NOTE: Fan will be loose, but cannot be removed until

after blower housing is removed.

1. Remove screws securing screen and remove screen.

2. Remove spacers, paying attention to curvature of spring washers between spacers and fan.

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 ﬂ ywheel, as these parts could become cracked or damaged.

1. Use a ﬂ ywheel strap wrench or holding tool to hold ﬂ 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 ﬂ 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™ switch. (Green wire, red terminal). Remove switch from oil pan only 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 or TMAP 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 106-111.

94 62 690 05 Rev. EKohlerEngines.com

Page 95

Disassembly/Inspection and Service

Remove Oil Filter Housing

Oil Filter Housing Components

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.

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.

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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Page 96

Disassembly/Inspection and Service

Cylinder Head Components

Style B Style 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

Y Rocker Arm Screw Z

Hydraulic Lifter

Style A (Ribbed)

Hydraulic Lifter

Style B (Smooth)

Non-adjustable Valve

Train (Non-AVT)

W Adjusting Nut X

Adjustable Valve

Train (AVT)

96 62 690 05 Rev. EKohlerEngines.com

Page 97

Disassembly/Inspection and Service

Remove Spark Plugs

Remove spark plug from each cylinder head.

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 diﬀ erent.

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

removed, or if seal is deteriorated in any way. Never reuse an old seal.

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

required.

2. Compress valve springs using a valve spring compressor.

3. Once valve spring is compressed, remove following items:

● Valve spring keepers.

● Valve spring retainers.

● Valve springs.

● Valve spring caps.

● Intake and exhaust valves (mark position).

● Valve stem seals.

4. Repeat above procedure for other cylinder head. Do not interchange parts from 1 cylinder head to another.

9762 690 05 Rev. E KohlerEngines.com

Page 98

Disassembly/Inspection and Service

Inspection and Service Valve Details

EXHAUST VALVE INTAKE VALVE

F F

E E

G G

INT

H H

EXH

Dimension Intake Exhaust

A Seat Angle 44.5° 44.5°

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.)

After cleaning, check ﬂ atness of cylinder head and corresponding top surface of crankcase using a surface plate or precision straight edge 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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Page 99

Disassembly/Inspection and Service

Recondition valve seat inserts following instructions provided with valve seat cutter being used. Final cut should be made with an 44.5° 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.

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 Thrust

M Breather Assembly N Oil Seal O

Bearing

(Flange PTO)

J Oil Pan Gasket K Breather Filter L Breather Gasket

Crankshaft Non-

Thrust Bearing

(PTO)

P Check Ball Kit

9962 690 05 Rev. E KohlerEngines.com

Page 100

Disassembly/Inspection and Service

1,4

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

1,4

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.

100 62 690 05 Rev. EKohlerEngines.com

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

Specifications and Main Features

Frequently Asked Questions

User Manual

Safety

Maintenance

Tools and Aids

Troubleshooting

Air Cleaner/Intake

Governor System

ELECTRONIC GOVERNOR

MECHANICAL GOVERNOR

Lubrication System

Electrical System

Starter System

Disassembly/Inspection and Service