Kohler SV470, SV620, SV480, SV530, SV540 Service Manual

...
Page 1
&285$*(6969
9(57,&$/&5$1.6+$)7
6(59,&(0$18$/
Page 2
Page 3
Contents
Section 1. Safety and General Information .............................................................................
Section 2. Tools & Aids .............................................................................................................
Section 3. Troubleshooting ......................................................................................................
Section 5. Fuel System and Governor .....................................................................................
Section 6. Lubrication System .................................................................................................
1
2
3
4
5
6
Section 7. Electrical System and Components ......................................................................
Section 8. Disassembly.............................................................................................................
Section 9. Inspection and Reconditioning ..............................................................................
Section 10. Reassembly............................................................................................................
Section 11. Emission Compliance Systems............................................................................
7
8
9
10
11
Page 4
Page 5
Safety and General Information
Section 1
Safety and General Information
Safety Precautions
To ensure safe operation please read the following statements and understand their meaning. Also refer to your equipment manufacturer's manual for other important safety information. This manual contains safety precautions which are explained below. Please read carefully.
WARNING
Warning is used to indicate the presence of a hazard that can cause severe personal injury, death, or substantial property damage if the warning is ignored.
CAUTION
Caution is used to indicate the presence of a hazard that will or can cause minor personal injury or property damage if the caution is ignored.
Section 1
1
NOTE
Note is used to notify people of installation, operation, or maintenance information that is important but not hazard-related.
For Your Safety!
These precautions should be followed at all times. Failure to follow these precautions could result in injury to yourself and others.
WARNING
Accidental Starts can cause severe injury or death.
Disconnect and ground spark plug leads before servicing.
Accidental Starts!
ȱǯȱȱ ȱȱȱȱ¢ȱȱ ǯȱBefore working on the engine
or equipment, disable the engine as follows: 1) Disconnect the spark plug lead(s). 2) Disconnect negative (-) baery cable from baery.
WARNING
Rotating Parts can cause severe injury.
Stay away while engine is in operation.
Rotating Parts!
Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate the engine with covers, shrouds, or guards removed.
Hot Parts can cause severe burns.
Do not touch engine while operating or just aer stopping.
Hot Parts!
Engine components can get extremely hot from operation. To prevent severe burns, do not touch these areas while the engine is running, or immediately aer it is turned o. Never operate the engine with heat shields or guards removed.
WARNING
1.1
Page 6
Section 1 Safety and General Information
WARNING
Explosive Fuel can cause res and severe burns.
Do not ll the fuel tank while the engine is hot or running.
Explosive Fuel!
Gasoline is extremely ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or ames. Do not fill the fuel tank while the engine is hot or running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent.
WARNING
WARNING
Carbon Monoxide can cause severe nausea, fainting or death.
Avoid inhaling exhaust fumes, and never run the engine in a closed building or conned area.
Lethal Exhaust Gases!
Engine exhaust gases contain poisonous carbon monoxide. Carbon monoxide is odorless, colorless, and can cause death if inhaled. Avoid inhaling exhaust fumes, and never run the engine in a closed building or conned area.
WARNING
Explosive Gas can cause res and severe acid burns.
Charge baery only in a well ventilated area. Keep sources of ignition away.
Explosive Gas!
Baeries produce explosive hydrogen gas while being charged. To prevent a re or explosion, charge baeries only in well ventilated areas. Keep sparks, open ames, and other sources of ignition away from the baery at all times. Keep baeries out of the reach of children. Remove all jewelry when servicing baeries.
Before disconnecting the negative (-) ground cable, make sure all switches are OFF. If ON, a spark will occur at the ground cable terminal which could cause an explosion if hydrogen gas or gasoline vapors are present.
Cleaning Solvents can cause severe injury or death.
Use only in well ventilated areas away from ignition sources.
Flammable Solvents!
Carburetor cleaners and solvents are extremely ammable. Keep sparks, ames, and other sources of ignition away from the area. Follow the cleaner manufacturer’s warnings and instructions on its proper and safe use. Never use gasoline as a cleaning agent.
1.2
CAUTION
Electrical Shock can cause injury.
Do not touch wires while engine is running.
Electrical Shock!
Never touch electrical wires or components while the engine is running. They can be sources of electrical shock.
Page 7
Engine Identification Numbers
When ordering parts, or in any communication involving an engine, always give the Model, Specication, and Serial Numbers of the engine.
The engine identication numbers appear on a decal axed to the engine shrouding. See Figure 1-1. An explanation of these numbers is shown in Figure 1-2.
Section 1
Safety and General Information
1
Identification Decal
Figure 1-1. Engine Identification Decal Location.
A. Model No. Courage Vertical Shaft Engine
Numerical Designation
B. Spec. No. Engine Model
Model 69
69  69  69  69  69  69  69
C. Serial No.
Year Manufactured Code
Code Year
                          
SV 540 S
Version Code
6 (OHFWULF6WDUW
SV540-0001
First spec written in this model series
3205810334
Factory Code
Figure 1-2. Explanation of Engine Identification Numbers.
1.3
Page 8
Section 1 Safety and General Information
Oil Recommendations
Using the proper type and weight of oil in the crankcase is extremely important, as is checking oil daily and changing oil regularly. Failure to use the correct oil or using dirty oil causes premature engine wear and failure.
Oil Type
Use high-quality detergent oil of API (American Petroleum Institute) service class SJ or higher. Select
the viscosity based on the air temperature at the time of operation as shown below.
RECOMMENDED SAE VISCOSITY GRADES
10W-30
**
5W-20, 5W-30
°F -20 0 20 32 40 60 80 100
°C -30 -20 -10 0 10 20 30 40
TEMPERATURE RANGE EXPECTED BEFORE NEXT OIL CHANGE
* Use of synthetic oil having 5W-20 or 5W-30 rating is acceptable,
up to 4°C (40°F)
** Synthetic oils will provide better starting in extreme cold below
23°C (-10°F)
NOTE: Using other than service class SJ or higher
oil or extending oil change intervals longer than recommended can cause engine damage.
NOTE: Synthetic oils meeting the listed
classifications may be used with oil changes performed at the recommended intervals. However to allow piston rings to properly seat, a new or rebuilt engine should be operated for at least 50 hours using standard petroleum based oil before switching to synthetic oil.
A logo or symbol on oil containers identies the API service class and SAE viscosity grade. See Figure 1-3.
Figure 1-3. Oil Container Logo.
*
E
S
I
P
A
SAE
10W-30
V
R
I
Kohler 10W-30
C
E
S
J
Refer to Section 6 - Lubrication System for detailed oil check, oil change, and oil lter change procedures.
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or flames. Do not fill the fuel tank while the engine is hot or running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent.
General Recommendations
Purchase gasoline in small quantities and store
in clean, approved containers. A container with a capacity of 2 gallons or less with a pouring spout is recommended. Such a container is easier to handle and helps eliminate spillage during refueling.
Do not use gasoline le over from the previous season, to minimize gum deposits in your fuel system and to ensure easy starting.
Do not add oil to the gasoline.
Do not overll the fuel tank. Leave room for the fuel to expand.
Fuel Type
For best results use only clean, fresh, unleaded gasoline with a pump sticker octane rating of 87 (R+M)/2 or higher. In countries using the Research Octane Number (RON), it should be 90 octane
minimum. Leaded gasoline is not recommended and must not be used on EFI engines or on other models where exhaust emissions are regulated.
Gasoline/Alcohol Blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler engines. Other gasoline/alcohol blends including E20 and E85 are not to be used and not approved. Any failures resulting from use of these fuels will not be warranted.
Gasoline/Ether Blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded gasoline blends (up to a maximum of 15% MTBE by volume) are approved as a fuel for Kohler engines. Other gasoline/ether blends are not approved.
1.4
Page 9
Periodic Maintenance
Section 1
Safety and General Information
WARNING: Accidental Starts!
ȱǯȱȱȱȱȱȱ¢ȱȱǯȱBefore working on the engine or equipment, disable the engine as follows: 1) Disconnect the spark plug lead(s). 2) Disconnect negative (-) baery cable from baery.
Maintenance Schedule
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
service center.
Maintenance RequiredFrequency
• Fill fuel tank.
Daily or Before
Starting Engine
Annually
or Every 25 Hours
Annually or
Every 100 Hours
Every 200 Hours
• Check oil level.
• Check air cleaner for dirty¹, loose, or damaged parts.
• Check air intake and cooling areas, clean as necessary¹.
• Service precleaner element¹ (if equipped).
• Service air cleaner element¹ (if not equipped with precleaner).
• Replace air cleaner element¹ (if equipped with precleaner).
• Change oil and lter (more frequently under severe conditions).
• Remove cooling shroud and clean cooling areas.
• Check that all fasteners are in place and components are properly secured.
• Replace fuel filter.
• Check spark plug condition and gap.
• Have valve lash checked/adjusted2.
1
Every 500 Hours
¹Perform these maintenance procedures more frequently under extremely dusty, dirty conditions. ²Have a Kohler Engine Service Dealer perform this service.
Storage
If the engine will be out of service for two months or more, use the following storage procedure:
1. Clean the exterior surfaces of the engine.
2. Change the oil and oil lter while the engine is still warm from operation. See Change Oil and Oil Filter in Section 6.
3. The fuel system must be completely emptied, or the gasoline must be treated with a stabilizer to prevent deterioration. If you choose to use a stabilizer, follow the manufacturer’s recommendations, and add the correct amount for the capacity of the fuel system. Fill the fuel tank with clean, fresh gasoline. Run the engine for 2-3 minutes to get stabilized fuel into the carburetor.
• Have bendix starter drive serviced².
• Replace spark plug.
To empty the system, run the engine until the
tank and system are empty.
4. Due to the deep recess around the spark plug, blow out the cavity with compressed air. Remove the spark plug. The spark plug is most accessible when the blower housing is removed for cleaning.
Add one tablespoon of engine oil into the spark
plug hole. Install the plug, but do not connect the plug lead. Crank the engine two or three revolutions. Connect the plug lead.
5. Reinstall the blower housing, if removed previously, and torque the blower housing screws to 7.5 N·m (65 in. lb.).
6. Store the engine in a clean, dry place.
1.5
Page 10
Section 1 Safety and General Information
VALVE COVER VIEW
Dimensions in millimeters. Inch equivalents shown in ().
Figure 1-4. Typical Engine Dimensions.
1.6
Page 11
Safety and General Information
General Specifications¹
Power (@ 3600 RPM, exceeds Society of Automotive Engineers-Small Engine Test Code J1940)
SV470 ............................................................................................................. 11.2 kW (15 HP)
SV480 ............................................................................................................. 11.9 kW (16 HP)
SV530 ............................................................................................................. 12.7 kW (17 HP)
SV540 .............................................................................................................. 13.4 kW (18 HP)
SV590 ............................................................................................................. 14.1 kW (19 HP)
SV600 .............................................................................................................. 14.9 kW (20 HP)
SV610 .............................................................................................................. 15.7 kW (21 HP)
SV620 .............................................................................................................. 16.4 kW (22 HP)
Bore
SV470, SV480 (Early Models Only) ............................................................. 84 mm (3.30 in.)
SV470, SV480, SV530, SV540 ........................................................................89 mm (3.50 in.)
SV590, SV600, SV610, SV620 ........................................................................94 mm (3.70 in.)
Stroke ...................................................................................................................... 86 mm (3.38 in.)
Displacement
SV470, SV480 (Early Models Only) ............................................................. 477 cc (29.1 cu. in.)
SV470, SV480, SV530, SV540 ........................................................................535 cc (32.6 cu. in.)
SV590, SV600, SV610, SV620 ........................................................................597 cc (36.4 cu. in.)
Section 1
1
Compression Ratio
SV470, SV480, SV530, SV540 ........................................................................9.4:1
SV590, SV600, SV610, SV620 ........................................................................8.5:1
Dry Weight .............................................................................................................35.8 kg (79 lb.)
Oil Capacity (with lter) .....................................................................................1.04-1.30 L (1.1-1.4 qt.)
Angle of Operation - Maximum (at Full Oil Level) All Directions ...............25° Intermient
Air Cleaner Base
Hex Nut Fastener Torque .................................................................................... 5.5 N·m (48 in. lb.)
Mounting Screw Fastener Torque (Install Dry - DO NOT OIL) ....................8.0 N·m (70 in. lb.) Into new as-cast hole
5.5 N·m (48 in. lb.) Into used hole
Blower Housing and Sheet Metal
M6 Fasteners Torque ..................................................................11.6 N·m (99 in. lb.) Into new as-cast hole
7.7 N·m (68 in. lb.) Into used hole
Cam Lever
Cam Lever Fastener Torque ...................................................... 8.0-10.5 N·m (70-94.0 in. lb.) Into new as-cast hole
7.1-8.6 N·m (61.8-74.8 in. lb.) Into used hole
Cam Gears
End Play .............................................................................................................. 0.5/1.5 mm (0.019/0.059 in.)
Running Side Clearance .................................................................................... 0.02/0.13 mm (0.001/0.005 in.)
Cam Gear-to-Cam Sha Running Assembly ................................................. 0.02/0.10 mm (0.001/0.004 in.)
Carburetor
Fuel Bowl Retaining Screw Torque ................................................................. 5.1-6.2 N·m (45-55 in. lb.)
1
Values are in metric units. Values in parentheses are English equivalents. Lubricate threads with engine oil prior
to assembly, EXCEPT for air cleaner base thread forming screw - install dry.
1.7
Page 12
Section 1 Safety and General Information
Closure Plate
Closure Plate Fastener Torque ........................................................................ 24.5 N·m (216 in. lb.)
Balance Weight Guide Channel Width
New .............................................................................................................. 17.95/18.05 mm (0.707/0.711 in.)
Max. Wear Limit ......................................................................................... 18.13 mm (0.714 in.)
Connecting Rod
Cap Fastener Torque (torque in 2 increments).............................................. 5.5, 11.5 N·m (50, 100 in. lb.)
Connecting Rod-to-Crankpin Running Clearance
New ............................................................................................................... 0.03/0.055 mm (0.0012/0.0022 in.)
Max. Wear Limit .......................................................................................... 0.07 mm (0.0025 in.)
Connecting Rod-to-Crankpin Side Clearance ................................................ 0.25/0.59 mm (0.0098/0.0232 in.)
Connecting Rod-to-Piston Pin Running Clearance ....................................... 0.015/0.028 mm (0.0006/0.0011 in.)
Piston Pin End I.D.
New ............................................................................................................... 22.015/22.023 mm (0.8667/0.8670 in.)
Max. Wear Limit .......................................................................................... 22.036 mm (0.8675 in.)
Crankcase
Governor Cross Sha Bore I.D.
New ............................................................................................................... 6.025/6.05 mm (0.2372/0.2382 in.)
Max. Wear Limit .......................................................................................... 6.063 mm (0.2387 in.)
Oil Drain Plug Torque ....................................................................................... 14.0 N·m (125 in. lb.)
Crankshaft
End Play (free) .................................................................................................... 0.225/1.025 mm (0.0089/0.040 in.)
Cranksha Bore in Crankcase I.D.
New .............................................................................................................. 41.965/41.990 mm (1.6521/1.6531 in.)
Max. Wear Limit ......................................................................................... 42.016 mm (1.654 in.)
Cranksha Bore in Closure Plate I.D.
New .............................................................................................................. 44.965/44.990 mm (1.7703/1.7713 in.)
Max. Wear Limit ......................................................................................... 45.016 mm (1.7723 in.)
Flywheel End Main Bearing Journal O.D.
New - Before Serial No. 3703200003 ....................................................... 44.913/44.935 mm (1.7682/1.7691 in.)
New - Aer Serial No. 3703200013 ......................................................... 44.870/44.895 mm (1.7665/1.7675 in.)
O.D. - Max. Wear Limit ............................................................................. 44.84 mm (1.765 in.)
Max. Taper .................................................................................................. 0.0220 mm (0.0009 in.)
Max. Out of Round .................................................................................... 0.025 mm (0.001 in.)
PTO End Main Bearing Journal O.D.
New - Before Serial No. 3703200003 ........................................................ 41.913/41.935 mm (1.6501/1.6510 in.)
New - Aer Serial No. 3703200013 .......................................................... 41.855/41.880 mm (1.6478/1.6488 in.)
O.D. - Max. Wear Limit ............................................................................. 41.83 mm (1.647 in.)
Max. Taper .................................................................................................. 0.020 mm (0.0008 in.)
Max. Out of Round .................................................................................... 0.025 mm (0.001 in.)
1.8
Page 13
Section 1
Safety and General Information
Crankshaft (Continued)
Cranksha Bore in Closure Plate Running Clearance
New - Before Serial No. 3703200003 ........................................................ 0.030/0.077 mm (0.0012/0.0030 in.)
New - Aer Serial No. 3703200013 .......................................................... 0.070/0.120 mm (0.0027/0.0047 in.)
Cranksha Bore in Crankcase Running Clearance
New - Before Serial No. 3703200003 ........................................................ 0.030/0.077 mm (0.0012/0.0030 in.)
New - Aer Serial No. 3703200013 .......................................................... 0.085/0.135 mm (0.0033/0.0053 in.)
Connecting Rod Journal O.D.
New .............................................................................................................. 40.982/41.000 mm (1.6134/1.6141 in.)
Max. Wear Limit ......................................................................................... 40.964 mm (1.612 in.)
Max. Taper .................................................................................................. 0.012 mm (0.0005 in.)
Max. Out of Round .................................................................................... 0.025 mm (0.001 in.)
Cranksha T.I.R.
PTO End, Cranksha in Engine ............................................................... 0.15 mm (0.0059 in.)
Entire Cranksha, in V-Blocks ................................................................. 0.10 mm (0.0039 in.)
Cranksha Eccentrics O.D.
New .............................................................................................................. 66.940/66.970 mm (2.6354/2.6366 in.)
Max. Wear Limit ......................................................................................... 66.89 mm (2.633 in.)
1
Balance Weight
Balance Weight Bearing Surface I.D.
New .............................................................................................................. 67.011/67.086 mm (2.6382/2.6412 in.)
Max. Wear Limit ......................................................................................... 67.140 mm (2.6430 in.)
Balance Weight Pin O.D.
New .............................................................................................................. 11.950/11.975 mm (0.4705/0.4715 in.)
Max. Wear Limit ......................................................................................... 11.900 mm (0.4685 in.)
Guide Shoe Width - Before Serial No. 3618000003
New ............................................................................................................. 17.85/17.90 mm (0.703/0.705 in.)
Max. Wear Limit ......................................................................................... 17.75 mm (0.6988 in.)
Guide Shoe Hole I.D.
New .............................................................................................................. 12.000/12.025 mm (0.4724/0.4734 in.)
Max. Wear Limit ......................................................................................... 12.050 mm (0.4744 in.)
Linkage Pin O.D. (Crankcase) - Aer Serial No. 3618000013
New .............................................................................................................. 11.964/11.975 mm (0.4710/0.4715 in.)
Max. Wear Limit ......................................................................................... 11.900 mm (0.4685 in.)
Balance Weight Linkage- Aer Serial No. 3618000013
New .............................................................................................................. 11.985/12.010 mm (0.4719/0.4728 in.)
Max. Wear Limit ......................................................................................... 12.035 mm (0.4738 in.)
Balance Weight Screw Torque ......................................................................... 10.9-13.2 N·m (95.0-115.0 in. lb.)
1.9
Page 14
Section 1 Safety and General Information
Cylinder Bore
Cylinder Bore I.D. New
SV470, SV480-00XX .................................................................................. 84.000/84.025 mm (3.307/3.308 in.)
SV470, SV480-01XX .................................................................................. 89.000/89.025 mm (3.504/3.505 in.)
SV530, SV540 ............................................................................................. 89.000/89.025 mm (3.504/3.505 in.)
SV590, SV600, SV610, SV620 ................................................................... 94.010/94.035 mm (3.701/3.702 in.)
Max. Wear Limit
SV470, SV480-00XX .................................................................................. 84.073 mm (3.310 in.)
SV470, SV480-01XX .................................................................................. 84.073 mm (3.310 in.)
SV530, SV540 ............................................................................................. 89.073 mm (3.507 in.)
SV590, SV600, SV610, SV620 ................................................................... 94.073 mm (3.704 in.)
Max. Taper .................................................................................................. 0.05 mm (0.002 in.)
Max. Out of Round .................................................................................... 0.12 mm (0.0047 in.)
Cylinder Head
Cylinder Head Fastener Torque (torque in 2 increments) .......................... 20.5, 41.0 N·m (180, 360 in. lb.)
Max. Out-of-Flatness ........................................................................................ 0.8 mm (0.003 in.)
Rocker Arm Pivot Stud Torque ....................................................................... 13.5 N·m (120 in. lb.)
Rocker Arm Adjustment Nut Set Screw ........................................................ 5.5 N·m (50 in. lb.)
Electric Starter
Thru Bolt Torque ............................................................................................... 3.3-3.9 N·m (30-35 in. lb.)
Mounting Nut Torque ...................................................................................... 3.6 N·m (32 in. lb.)
Nut (Top) Positive (+) Brush Lead Terminal ................................................. 1.6-2.8 N·m (15-25 in. lb.)
Nut (Flange) Positive (+) Brush Lead Terminal ............................................ 2.2-4.5 N·m (20-40 in. lb.)
Fan/Flywheel
Flywheel Retaining Screw Torque M12 ......................................................... 88.0 N·m (65 . lb.)
Flywheel Retaining Screw Torque M10 ......................................................... 66.5 N·m (49 . lb.)
Governor
Governor Cross Sha-to-Crankcase Running Clearance ........................... 0.013/0.075 mm (0.0005/0.003 in.)
Governor Cross Sha O.D.
New .............................................................................................................. 5.975/6.012 mm (0.2352/0.2367 in.)
Max. Wear Limit ......................................................................................... 5.962 mm (0.2347 in.)
Governor Gear Sha-to-Governor Gear Running Clearance ..................... 0.09/0.16 mm (0.0035/0.0063 in.)
Governor Gear Sha O.D.
New ............................................................................................................. 5.99/6.00 mm (0.2358/0.2362 in.)
Max. Wear Limit ........................................................................................ 5.977 mm (0.02353 in.)
Ignition
Spark Plug Type (Champion® or Equivalent) ............................................... RC12YC or QC12YC
Spark Plug Gap .................................................................................................. 0.76 mm (0.030 in.)
1.10
Page 15
Section 1
Safety and General Information
Ignition (Continued)
Spark Plug Torque............................................................................................. 24-30 N·m (18-22 . lb.)
Ignition Module Air Gap ................................................................................ 0.203/0.305 mm (0.008/0.012 in.)
Ignition Module Fastener Torque ................................................................... 6.0 N·m (55 in. lb.) Into new as-cast hole
4.0 N·m (35 in. lb.) Into used hole
Muer
Muffler Retaining Nuts Torque ...................................................................... 24.4 N·m (216 in. lb.)
Oil Filter
Oil Filter Torque ................................................................................................ refer to the oil lter for instructions.
Oil Filter Pad Pipe Plug
1/8” N.P.T.F. Torque .......................................................................................... 4.5-5.0 N·m (40-46 in. lb.)
Oil Pump
Mounting Screw Torque .............................................................5.0-7.5 N·m (44.4-66.0 in. lb.) Into new as-cast hole
3.8-4.6 N·m (33.3-40.3 in. lb.) Into used hole
Pump Gears-to-Crankcase Side Clearance .................................................... 0.165/0.315 mm (0.0065/0.0124 in.)
1
Oil Sentry
Pressure Switch Torque .................................................................................... 4.5-5.0 N·m (40-45 in. lb.)
Piston, Piston Rings, and Piston Pin
Piston Pin Bore I.D.
New .............................................................................................................. 22.006/22.012 mm (0.8685/0.8666 in.)
Max. Wear Limit ......................................................................................... 22.025 mm (0.8671 in.)
Piston Pin O.D.
New .............................................................................................................. 21.995/22.0 mm (0.8659/0.8661 in.)
Max. Wear Limit ......................................................................................... 21.994 mm (0.8658 in.)
Top Compression Ring-to-Groove Side Clearance ..................................... 0.04 mm (0.0016 in.)
Middle Compression Ring-to-Groove Side Clearance ............................... 0.04 mm (0.0016 in.)
Top and Middle Compression Ring End Gap New Bore
Top Ring .................................................................................................... 0.15/0.40 mm (0.006/0.016 in.)
Middle Ring .............................................................................................. 0.30/0.55 mm (0.012/0.022 in.)
Used Bore (max.) ........................................................................................ 0.77 mm (0.030 in.)
Piston Thrust Face O.D.² SV470, SV480-00XX
New ............................................................................................................ 83.948/83.962 mm (3.3050/3.3056 in.)
Max. Wear Limit ....................................................................................... 83.828 mm (3.3003 in.)
SV470, SV480-01XX
New ............................................................................................................ 88.948/88.962 mm (3.5018/3.5024 in.)
Max. Wear Limit ....................................................................................... 88.828 mm (3.4972 in.)
²Measure 8 mm (0.314 in.) above the boom of the piston skirt at right angles to the piston pin.
1.11
Page 16
Section 1 Safety and General Information
Piston, Piston Rings, and Piston Pin (Continued)
SV530, SV540
New ............................................................................................................ 88.948/88.962 mm (3.5018/3.5024 in.)
Max. Wear Limit ....................................................................................... 88.828 mm (3.4972 in.)
SV590, SV600, SV610, SV620
New ............................................................................................................ 93.928/93.942 mm (3.6980/3.6985 in.)
Max. Wear Limit ....................................................................................... 93.828 mm (3.6940 in.)
2
Piston Thrust Face-to-Cylinder Bore
SV470, SV480, SV530, SV540 .................................................................... 0.045 mm (0.0018 in.)
SV560, SV590, SV600, SV610, SV620 ....................................................... 0.0880 mm (0.0035 in.)
Rectifier-Regulator
Mounting Screw Torque ................................................................................... 6.0 N·m (55 in. lb.) Into new as cast hole
4.0 N·m (35 in. lb.) Into used hole
Speed Control
Speed Control Bracket Assembly Fastener Torque ......................................11.0 N·m (95 in. lb.) Into new as-cast hole
7.5 N·m (65 in. lb.) Into used hole
Stator
Stator Mounting Screw Torque ....................................................................... 6.0 N·m (55 in. lb.) Into new as-cast hole
4.0 N·m (35 in. lb.) Into used hole
Throttle/Choke Controls
Governor Control Lever Fastener Torque ..................................................... 7.0-8.5 N·m (60-75 in. lb.)
Running Clearance
Valve Cover
Valve Cover Fastener Torque........................................................................... 11.0 N·m (95 in. lb.) Into new as-cast hole
7.5 N·m (65 in. lb.) Into used hole
Valves and Valve Lifters
Intake Valve Lash3 ............................................................................................. 0.127 mm (0.005 in.)
Exhaust Valve Lash3 .......................................................................................... 0.178 mm (0.007 in.)
Intake Valve Minimum Li ............................................................................. 8.9 mm (0.350 in.)
Exhaust Valve Minimum Li .......................................................................... 8.9 mm (0.350 in.)
Nominal Valve Seat Angle ............................................................................... 45°
Intake Valve Stem-to-Valve Guide Running Clearance ............................... 0.038/0.076 mm (0.0015/0.003 in.)
Exhaust Valve Stem-to-Valve Guide Running Clearance ............................ 0.050/0.88 mm (0.0020/0.0035 in.)
Intake Valve Guide I.D.
New .............................................................................................................. 6.038/6.058 mm (0.2377/0.2385 in.)
Max. Wear Limit ......................................................................................... 6.135 mm (0.2415 in.)
2
Measure 8 mm (0.314 in.) above the boom of the piston skirt at right angles to the piston pin.
3
Check valve lash every 200 hours, adjust as required.
1.12
Page 17
Section 1
Safety and General Information
Valves and Valve Lifters (Continued)
Intake Valve Stem Diameter
New .............................................................................................................. 5.982/6.0 mm (0.2355/0.2362 in.)
Exhaust Valve Guide I.D.
New .............................................................................................................. 6.038/6.058 mm (0.2377/0.2385 in.)
Max. Wear Limit ......................................................................................... 6.160 mm (0.2425 in.)
Exhaust Valve Stem Diameter
New .............................................................................................................. 5.970/5.988 mm (0.235/0.2357 in.)
General Torque Values
Metric Fastener Torque Recommendations for Standard Applications
Tightening Torque: N·m (in. lb.) + or - 10%
1
Property Class
Noncritical
4.8
Size 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)
5.8 8.8 10.9 12.9
Fasteners
Into Aluminum
Tightening Torque: N·m (ft. lb.) + or - 10%
Property Class
4.8
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 (55) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)
5.8 8.8 10.9 12.9
Oil Drain Plugs Tightening Torque: N•m (English)
Size 1/8" NPT 1/4" 3/8" 1/2" 3/4" X-708-1
Into Cast Iron
17.0 (150 in. lb.)
20.3 (180 in. lb.)
27.1 (20 . lb.)
33.9 (25 . lb.)
27.1/33.9 (20/25 . lb.)
Into Aluminum
4.5 (40 in. lb.)
11.3 (100 in. lb.)
13.6 (120 in. lb.)
17.6 (13 . lb.)
21.7 (16 . lb.)
27.1/33.9 (20/25 . lb.)
Conversions
N·m = in. lb. x 0.113 N·m = . lb. x 1.356 in. lb. = N·m x 8.85 . lb. = N·m x 0.737
Noncritical
Fasteners
Into Aluminum
Torque
1.13
Page 18
Section 1 Safety and General Information
1.14
Page 19
Section 2
Tools & Aids
Section 2
Tools & Aids
Certain quality tools are designed to help you perform specic disassembly, repair, and reassembly procedures. By using tools designed for the job, 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 the list of tools and their source.
Separate Tool Suppliers:
Kohler Tools Contact your source
of supply.
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
2
Tools
Description Source/Part No.
Balance Gear Timing Tool (K & M Series)
To hold balance gears in timed position when assembling engine.
Camsha Endplay Plate
For checking camsha endplay.
Camsha Seal Protector (Aegis)
To protect seal during camsha installation.
Cylinder Leakdown Tester
For checking combustion retention and if cylinder, piston, rings, or valves are worn.
Electronic Fuel Injection (EFI) Diagnostic Soware
Use with Laptop or Desktop PC.
EFI Service Kit
For troubleshooting and seing up an EFI engine.
Individual Components Available
Pressure Tester Noid Light
90° Adapter Oetiker Clamp Pliers Code Plug, Red Wire Code Plug, Blue Wire
Flywheel Holding Tool (CS Series) SE Tools KLR-82407
Flywheel Puller
To remove flywheel from engine.
Flywheel Strap Wrench
To hold flywheel during removal.
Kohler 25 455 06-S
(Formerly Y-357)
SE Tools KLR-82405
SE Tools KLR-82417
Kohler 25 761 05-S
Kohler 25 761 23-S
Kohler 24 761 01-S
Design Technology Inc.
DTI-019 DTI-021 DTI-023 DTI-025 DTI-027 DTI-029
SE Tools KLR-82408
SE Tools KLR-82409
2.1
Page 20
Section 2 Tools & Aids
Tools (Continued)
Description Source/Part No.
Hydraulic Valve Lier Tool
To remove and install hydraulic liers.
Ignition System Tester
For testing output on all systems, except CD. For testing output on capacitive discharge (CD) ignition system.
Oset Wrench (K & M Series)
To remove and reinstall cylinder barrel retaining nuts.
Oil Pressure Test Kit
To test and verify oil pressure.
Rectifier-Regulator Tester (120 volt current) Rectifier-Regulator Tester (240 volt current)
Used to test rectier-regulators.
Kohler 25 761 38-S
Kohler 25 455 01-S Kohler 24 455 02-S
SE Tools KLR-82410
Kohler 25 761 06-S
Kohler 25 761 20-S Kohler 25 761 41-S
Individual Components Available CS-PRO Regulator Test Harness Special Regulator Test Harness with Diode
Spark Advance Module (SAM) Tester
To test the SAM (ASAM and DSAM) on engines with SMART-SPARK™.
Starter Retaining Ring Tool (Inertia Drive)
To remove and reinstall drive retaining rings (excluding FASCO starters).
Starter Servicing Kit (All Starters)
To remove and reinstall drive retaining rings and brushes. Individual Component Available
Starter Brush Holding Tool (Solenoid Shift)
Tachometer (Digital Inductive)
For checking operating speed (RPM) of an engine.
Vacuum/Pressure Tester
Alternative to a water manometer.
Valve Guide Reamer (K & M Series)
For sizing valve guides after installation.
Design Technology Inc.
DTI-031 DTI-033
Kohler 25 761 40-S
Kohler 25 761 18-S
SE T ools KLR-8241 1
SE T ools KLR-82416
Design T echnology Inc.
DTI-110
Kohler 25 761 22-S
SE T ools KLR-1 1843
2.2
Page 21
Section 2
Tools & Aids
Aids
Description Source/Part No.
Camsha Lubricant (Valspar ZZ613) Kohler 25 357 14-S
Dielectric Grease (GE/Novaguard G661) Kohler 25 357 11-S
Dielectric Grease (Fel-Pro) Lubri-Sel
Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S
Electric Starter Drive Lubricant (Solenoid Shi) Kohler 52 357 02-S
RTV Silicone Sealant
Loctite® 5900 Heavy Body in 4 oz aerosol dispenser. Only oxime-based, oil resistant RTV sealants, such as those listed, are approved for use. Loctite® Nos. 5900 or 5910 are recommended for best sealing characteris­tics. Loctite® 5910 Loctite® Ultra Black 598 Loctite® Ultra Blue 587
Loctite® Ultra Copper
Spline Drive Lubricant Kohler 25 357 12-S
Kohler 25 597 07-S
2
2.3
Page 22
Section 2 Tools & Aids
Special Tools You Can Make
Flywheel Holding Tool
A flywheel holding tool can be made out of an old junk ywheel ring gear as shown in Figure 2-1, and used in place of a strap wrench.
1. Using an abrasive cut-o wheel, cut out a six
tooth segment of the ring gear as shown.
2. Grind off any burrs or sharp edges.
3. Invert the segment and place it between the ignition bosses on the crankcase so that the tool teeth engage the flywheel ring gear teeth. The bosses will lock the tool and ywheel in position for loosening, tightening or removing with a puller.
2. Remove the studs of a Posi-Lock rod or grind o the aligning steps of a Command rod, so the joint surface is flat.
3. Find a 1 in. long capscrew with the correct thread size to match the threads in the connecting rod.
4. Use a flat washer with the correct I.D. to slip on the capscrew and approximately 1” O.D. (Kohler Part No. 12 468 05-S). Assemble the capscrew and washer to the joint surface of the rod, as shown in Figure 2-2.
Figure 2-1. Flywheel Holding Tool.
Rocker Arm/Crankshaft Tool
A spanner wrench to li the rocker arms or turn the cranksha 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 the rod cap.
Figure 2-2. Rocker Arm/Crankshaft Tool.
2.4
Page 23
Section 3
Troubleshooting
Troubleshooting Guide
When troubles occur, be sure to check the simple
causes which, at rst, may seem too obvious to be
considered. For example, a starting problem could be
caused by an empty fuel tank.
Some common types of engine troubles are listed
below. Use these to help locate the possible cause(s).
Engine Cranks But Will Not Start
1. Empty fuel tank.
2. Fuel shut-o valve closed.
3. Poor fuel, dirt or water in the fuel system.
4. Clogged fuel line.
5. Spark plug lead disconnected.
6. Kill switch in o position.
7. Faulty spark plug.
8. Faulty ignition module.
9. Fuel solenoid malfunction.
10. Choke not closing.
11. Baery connected backwards.
12. Safety interlock system engaged.
Engine Starts But Does Not Keep Running
1. Restricted fuel tank cap vent.
2. Poor fuel, dirt or water in the fuel system.
3. Faulty or misadjusted choke or throle controls.
4. Loose wires or connections that short the kill
terminal of ignition module to ground.
5. Faulty cylinder head gasket.
6. Faulty carburetor.
7. Intake system leak.
Engine Starts Hard
1. PTO drive is engaged.
2. Poor fuel, dirt or water in the fuel system.
3. Clogged fuel line.
4. Loose or faulty wires or connections.
5. Faulty or misadjusted choke or throle controls.
6. Faulty spark plug.
7. Low compression.
8. Faulty ACR mechanism.
9. Weak spark.
10. Fuel pump malfunction causing lack of fuel.
Section 3
Troubleshooting
3
11. Engine overheated-cooling/air circulation
restricted.
12. Flywheel key sheared.
13. Intake system leak.
Engine Will Not Crank
1. PTO drive is engaged.
2. Baery is discharged.
3. Safety interlock switch is engaged.
4. Loose or faulty wires or connections.
5. Faulty key switch or ignition switch.
6. Faulty electric starter.
7. Seized internal engine components.
Engine Runs But Misses
1. Dirt or water in the fuel system.
2. Spark plug faulty or fouled.
3. Poor quality of fuel.
4. Spark plug lead boot loose on plug.
5. Loose wires or connections that intermiently short the kill terminal of ignition module to
ground.
6. Engine overheated.
7. Faulty ignition module or improperly gapped.
8. Carburetor adjusted incorrectly.
Engine Will Not Idle
1. Dirt or water in the fuel system.
2. Stale fuel and/or gum in carburetor.
3. Faulty spark plug.
4. Fuel supply inadequate.
5. Idle fuel adjusting needle improperly set.
6. Idle speed adjusting screw improperly set.
7. Low compression.
8. Restricted fuel tank cap vent.
9. Engine overheated-cooling system/air circulation
problem.
3.1
Page 24
Section 3 Troubleshooting
Engine Overheats
1. Air intake/grass screen, cooling ns, or cooling
shrouds clogged.
2. Excessive engine load.
3. Low crankcase oil level.
4. High crankcase oil level.
5. Faulty carburetor.
6. Lean fuel mixture.
Engine Knocks
1. Excessive engine load.
2. Low crankcase oil level.
3. Old or improper fuel.
4. Internal wear or damage.
5. Quality of fuel.
6. Incorrect grade of oil.
Engine Loses Power
1. Low crankcase oil level.
2. High crankcase oil level.
3. Dirty air cleaner element.
4. Dirt or water in the fuel system.
5. Excessive engine load.
6. Engine overheated.
7. Faulty spark plug.
8. Low compression.
9. Exhaust restriction.
10. Low baery.
11. Incorrect governor seing.
Engine Uses Excessive Amount of Oil
1. Incorrect oil viscosity/type.
2. Clogged, broken, or inoperative breather.
3. Worn or broken piston rings.
4. Worn cylinder bore.
5. Worn valve stems/valve guides.
6. Crankcase overfilled.
7. Blown head gasket/overheated.
• Check for buildup of dirt and debris on the crankcase, cooling ns, grass screen and other external surfaces. Dirt or debris on these areas can cause overheating.
• Check for obvious 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 the air cleaner cover and base for damage or indications of improper t and seal.
• Check the air cleaner element. Look for holes, tears, cracked or damaged sealing surfaces, or other damage that could allow unltered air into the engine. Also note if the element is dirty or clogged. These could indicate improper
maintenance.
• Check the carburetor throat for dirt. Dirt in the throat is further indication that the air cleaner was not functioning properly.
• Check if the oil level is within the operating range on the dipstick. If it is above, sni for gasoline
odor.
• Check the condition of the oil. Drain the oil into a container; it should 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 the wrong type or weight of oil was
used, the oil was not changed at the recommended
intervals, an over-rich fuel mixture, or weak ignition, to name a few possible causes.
Oil Leaks from Oil Seals, Gaskets
1. Clogged, broken, or inoperative breather.
2. Worn or broken piston rings.
3. Piston blowby, or leaky valves.
4. Restricted exhaust.
External Engine Inspection
Before cleaning or disassembling the engine, make a thorough inspection of its external appearance and condition. This inspection can give clues to what might be found inside the engine (and the cause)
when it is disassembled.
3.2
NOTE: It is good practice to drain oil at a location
away from the workbench. Be sure to allow ample time for complete drainage.
Cleaning the Engine
Aer inspecting the external condition of the engine, clean the engine thoroughly before disassembling it. Also clean individual components as the 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 the manufacturer’s instructions and safety precautions carefully.
Page 25
Section 3
Troubleshooting
Make sure all traces of the cleaner are removed before
the engine is reassembled and placed into operation.
Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil.
Basic Engine Tests
Crankcase Vacuum Test
A partial vacuum should be present in the
crankcase when the engine is operating. Pressure
in the crankcase (normally caused by a clogged or improperly-operating breather) can cause oil to be forced out at oil seals, gaskets, or other available spots.
Crankcase vacuum is best measured with a water manometer or vacuum/pressure test gauge. See Section 2. Complete instructions are provided with the
testers.
Test the crankcase vacuum with the manometer as follows:
1. Insert the rubber stopper into the oil ll hole.
Be sure the pinch clamp is installed on the hose and use the tapered adapters to connect
the hose between the stopper and one of the manometer tubes. Leave the other tube open to the atmosphere. Check that the water level in the
manometer is at the “0” line. Make sure the pinch clamp is closed.
2. Start the engine and run at no-load high idle speed (3200 to 3750 RPM).
3. Open the clamp and note the water level in the
tube.
The level in the engine side should be a minimum
of 10.2 cm (4 in.) above the level in the open side.
If the level in the engine side is the same as the
open side (no vacuum), or the level in the engine side is lower than the level in the open side (pressure), check for the conditions in the table
below.
4. Close the pinch clamp before stopping the engine.
To perform the test with the vacuum/pressure gauge:
1. Insert the stopper as in step 1.
2. Insert the barbed gauge ing into the hole in the
stopper. Be sure the gauge needle is at “0”.
3. Run the engine, as in step 2, and observe the gauge reading. Needle movement to the le of “0” is a vacuum, and movement to the right indicates a pressure. A minimum of 10.2 cm (4 in.) of vacuum should be present.
3
Incorrect Vacuum in Crankcase
Possible Cause Solution
1. Crankcase breather clogged or inoperative.
2. Seals and/or gaskets leaking. Loose or improperly torqued fasteners.
3. Piston blowby or leaky valves. Conrm with cylinder leakdown test.
4. Restricted exhaust.
1. Disassemble breather, clean parts thoroughly,
reassemble, and recheck pressure.
2. Replace all worn or damaged seals and gaskets.
Make sure all fasteners are tightened securely. Use appropriate torque values and sequences when necessary.
3. Recondition piston, rings, cylinder bore, valves, and valve guides.
4. Repair/replace restricted muer/exhaust system.
3.3
Page 26
Section 3 Troubleshooting
Compression Test
These engines are equipped with an automatic
compression release (ACR) mechanism. Because of the ACR mechanism, it is dicult to obtain an accurate compression reading. As an alternate, use the
leakdown test described below.
Cylinder Leakdown Test
A cylinder leakdown test can be a valuable alternative to a compression test. By pressurizing the combustion chamber from an external air source, you can determine if the valves or rings are leaking, and how badly.
The cylinder leakdown tester is a relatively simple, inexpensive leakdown tester for small engines. The tester includes a quick disconnect coupling for aaching the adapter hose and a holding tool.
Leakdown Test Instructions
1. Run the engine for 3-5 minutes to warm it up.
2. Remove the spark plug.
3. Rotate the cranksha until the piston is at top dead center of the compression stroke. You
will need to hold the engine in this position while testing. The holding tool supplied with
the tester can be used if the PTO end of the cranksha is accessible. Slide the holding tool onto the cranksha, align the slot with one of the mounting holes on the PTO face, and tighten it onto the cranksha. Install a 3/8" breaker bar into
the slot of the holding tool, so it is perpendicular to both the holding tool and cranksha, or insert
a shoulder bolt through the slot and thread it into
the mounting hole. If the ywheel end is more accessible, you can use a breaker bar and socket on the ywheel nut/screw to hold it in position. You may need an assistant to hold the breaker bar during testing. If the engine is mounted in a piece of equipment, you may be able to hold it by clamping or wedging a driven component. Just be certain that the engine cannot rotate o of
TDC in either direction.
4. Install the adapter into the spark plug hole, but
do not aach it to the tester at this time.
5. Connect an adequate air source (80-100 psi) to the tester.
6. Turn the regulator knob in the increase (clockwise) direction until the gauge needle is in
the yellow set area at the low (right) end of the
scale.
7. Connect the tester quick-disconnect to the
adapter. Note the gauge reading and listen for
escaping air at the carburetor inlet, exhaust
outlet, and/or crankcase breather.
8. Check your test results against the table below:
Leakdown Test Results
Air escaping from crankcase breather ................................................Defective rings or worn cylinder walls.
Air escaping from exhaust system ......................................................Defective exhaust valve.
Air escaping from carburetor ...............................................................Defective intake valve.
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.
3.4
Page 27
Air Cleaner and Air Intake System
Section 4
Air Cleaner and Air Intake System
Section 4
Air Cleaner
These engines are equipped with a replaceable, high density, paper air cleaner element. Some engines also have an oiled, foam precleaner, located in the outer air cleaner cover. See Figure 4-1.
Air Cleaner Base
Optional Foam Precleaner
Intake air is drawn in through the upper opening from the blower housing, passes through the precleaner (if so equipped), the paper element and then into the carburetor. The outer air cleaner cover is secured by two knobs, and removed by turning the knobs counterclockwise.
Air Cleaner Element
Air Cleaner Cover
4
Figure 4-1. Air Cleaner Assembly - Exploded View.
Check the air cleaner daily or before starting the engine. Check for and correct any buildup of dirt and
debris, and loose or damaged components.
NOTE: Operating the engine with loose or
damaged air cleaner components could allow unltered air into the engine causing premature wear and failure.
Air Cleaner Cover Knobs
Precleaner Service
If so equipped, wash and oil the precleaner annually or every 25 hours of operation (more oen under extremely dusty or dirty conditions).
1. Loosen the air cleaner cover knobs and remove the cover.
2. Remove the precleaner.
4.1
Page 28
Section 4 Air Cleaner and Air Intake System
3. Wash the precleaner in warm water with detergent. Rinse the precleaner thoroughly until all traces of detergent are eliminated. Squeeze out excess water (do not wring). Allow the precleaner to air dry.
4. Saturate the precleaner with new engine oil. Squeeze out all excess oil.
5. Reinstall the precleaner into the outer cover.
6. Install the air cleaner cover and secure with the two knobs.
7. When precleaner replacement is necessary, order Kohler Part No. 20 083 03-S.
Paper Element Service
Check the paper element annually or every 25 hours of operation (more oen under extremely dusty or dirty conditions). Clean or replace the element as necessary. Replace the air cleaner element annually or every 100 hours.
1. Remove the air cleaner cover and the precleaner (if so equipped), service as required.
2. Remove the air cleaner element with the integral rubber seal.
8. When element replacement is necessary, order
Kohler Part No. 20 083 02-S.
Inspect Air Cleaner Components
Whenever the air cleaner cover is removed, or the paper element or precleaner is serviced, check the following areas/components:
Outer Air Cleaner Cover - Make sure the air cleaner cover is in good condition, not cracked, damaged, or missing a retaining knob, which can aect the sealing ability of the air cleaner element.
Air Cleaner Base - Make sure the base is properly secured and not cracked or damaged. Since the air cleaner base and carburetor are secured to the intake port with common hardware, it is extremely important that the fasteners securing these components are tight at all times. The air cleaner base also provides the mounting points for the air cleaner cover retaining studs. Make sure the bosses are not cracked, broken or damaged, and the studs are properly secured.
Before reinstalling an air cleaner base that has been removed, make sure the metal bushings in the base mounting holes are present. See Figure 4-2. The bushings prevent damage to the base and maintain the proper mounting torque.
3. Gently tap the pleated side of the paper element to dislodge dirt. Do not wash the paper element or use pressurized air, as this will damage the element. Replace a dirty, bent, or damaged element with a genuine Kohler element. Handle new elements carefully; do not use if the rubber seal is damaged.
4. Clean all air cleaner components of any accumulated dirt or foreign material. Prevent any dirt from entering the throat of the carburetor.
5. Install the air cleaner element with the pleated side out and seat the rubber seal onto the edges of the air cleaner base.
6. Reinstall the precleaner (if so equipped), into the upper section of the air cleaner cover. Make sure the hole in the precleaner is aligned with the upper mounting knob. See Figure 4-1.
7. Reinstall the air cleaner cover and secure with the two knobs.
Figure 4-2. Bushings in Air Cleaner Base.
Breather Hose - Make sure the hose is not cracked or damaged, and aached to both the air cleaner base and valve cover.
NOTE: Damaged, worn, or loose air cleaner
components can allow unltered air into the engine causing premature wear and failure. Tighten or replace all loose or damaged components.
4.2
Page 29
Figure 4-3. Breather Hose.
Disassembly
The following procedure is for complete disassembly of all air cleaner components. As the removal of the air cleaner base also aects carburetor mounting and governor adjustment, steps 3 and 4 should only be performed if required. Detailed photos are provided in Sections 5, 8, and 10 for the various individual steps.
Section 4
Air Cleaner and Air Intake System
Reassembly
The following procedure is for complete assembly of all air cleaner components. Steps 1-3 are necessary only if the air cleaner base and/or the cover mounting studs were removed in Section 8, Disassembly.
1. Install the mounting studs into the air cleaner base if removed previously. Tighten the studs until boomed, or to the end of threads (do not force).
2. Install the air cleaner base gasket and air cleaner base, with the two metal spacers, onto the mounting stud(s) and/or alignment pin. Make sure the upper mounting tab is located above the closure plate. Install and nger tighten the hex ange nut(s). When a long M6 thread forming mounting screw is used, apply hand pressure to keep the parts from shiing, then remove the alignment pin and install the M6 thread forming screw. DO NOT OIL. Torque the nut(s) to
5.5 N·m (48 in. lb.). Torque the screw to 8.0 N·m
(70 in. lb.) into a new hole, or 5.5 N·m (48 in. lb.)
into a used hole, do not over tighten.
4
1. Loosen the air cleaner cover retaining knobs and remove the air cleaner cover.
2. Remove the foam precleaner (if so equipped), and the air cleaner element with formed rubber seal.
3. Disconnect the breather hose from the valve cover or air cleaner base.
NOTE: The air cleaner base should be removed
only if necessary.
4. Remove the two hex ange nuts from the mounting studs. If one stud and one thread forming screw is used; rst remove the thread forming screw on the right side of the carburetor inlet, which secures the air cleaner base, carburetor and gaskets. Insert a 3/16” diameter rod approximately 4” long, into the hole to serve as a temporary alignment pin. Be careful not to force the rod or damage the threads. Then remove the hex ange nut from the stud on the le side of the carburetor inlet. Carefully remove the air cleaner base and gasket. The cover mounting studs thread into the air cleaner base, and they should only be removed if necessary.
3. Reconnect the breather hose and perform the governor adjustment (Section 5, Initial Governor Adjustment).
4. Install the air cleaner element with the pleated side out and seat the rubber seal onto the edges of the air cleaner base.
5. Install the serviced precleaner (if so equipped) into the air cleaner cover. Make sure the hole in the precleaner is aligned with the upper mounting knob.
6. Reinstall the air cleaner cover and secure with the two knobs.
4.3
Page 30
Section 4 Air Cleaner and Air Intake System
Air Intake/Cooling System
Clean Air Intake/Cooling Areas
To ensure proper cooling, make sure the grass screen, cooling ns, and other external surfaces of the engine are kept clean at all times.
Annually or every 100 hours of operation, (more oen under extremely dusty, dirty conditions), remove the blower housing and any other cooling shrouds. Clean the cooling ns and external surfaces as necessary. Make sure all parts are reinstalled. Torque the M6 blower housing fasteners to 7.7 N·m (68.3 in. lb.).
NOTE: Operating the engine with a blocked grass
screen, dirty or plugged cooling ns, and/or cooling shrouds removed, will cause engine damage due to overheating.
4.4
Page 31
Fuel System and Governor
Section 5
Fuel System and Governor
Section 5
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well-ventilated, unoccupied buildings, away from sparks or ames. Do not ll the fuel tank while the engine is hot or running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent.
General Recommendations
Purchase gasoline in small quantities and store in clean, approved containers. A container with a capacity of 2 gallons or less with a pouring spout is recommended. Such a container is easier to handle and helps eliminate spillage during refueling.
• Do not use gasoline le over from the previous season, to minimize gum deposits in your fuel system and to ensure easy starting.
• Do not add oil to the gasoline.
• Do not overll the fuel tank. Leave room for the fuel to expand.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded gasoline blends (up to a maximum of 15% MTBE by volume) are approved as a fuel for Kohler engines. Other gasoline/ether blends are not approved.
Fuel System
The typical fuel system and related components include the fuel tank, in-line fuel lter, fuel pump, carburetor, and fuel lines. Some applications use gravity feed without a fuel pump.
Operation
The fuel from the tank is moved through the in-line lter and fuel lines by the fuel pump. On engines not equipped with a fuel pump, the fuel tank outlet is located above the carburetor inlet and gravity moves the fuel.
Fuel then enters the carburetor oat bowl and is moved into the carburetor body. There, the fuel is mixed with air. This fuel-air mixture is then burned in the engine combustion chamber.
Troubleshooting
Use the following procedure to check if fuel is reaching the combustion chamber.
5
Fuel Type
For best results use only clean, fresh, unleaded gasoline with a pump sticker octane rating of 87 (R+M)/2 or higher. In countries using the Research Octane Number (RON), it should be 90 octane minimum. Leaded gasoline is not recommended and must not be used on EFI engines or on other models where exhaust emissions are regulated.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler engines. Other gasoline/alcohol blends including E20 and E85 are not to be used and not approved. Any failures resulting from use of these fuels will not be warranted.
5.1
Page 32
Section 5 Fuel System and Governor
Fuel System Troubleshooting Guide
Test Conclusion
1. Check for the following: a. Make sure the fuel tank contains clean, fresh,
proper fuel. b. Make sure the vent in fuel cap is open. c. Make sure the fuel valve is open.
2. Check for fuel in the combustion chamber. a. Disconnect and ground spark plug lead. b. Close the choke on the carburetor. c. Crank the engine several times. d. Remove the spark plug and check for fuel at
the tip.
3. Check for fuel ow from the tank to the fuel pump. a. Remove the fuel line from the inlet ing of
the fuel pump. b. Hold the line below the boom of the tank.
Open the shuto valve (if so equipped) and
observe ow.
4. Check the operation of fuel pump. a. Remove the fuel line from the inlet ing of
the carburetor. b. Crank the engine several times and observe
ow.
2. If there is fuel at the tip of the spark plug, fuel is
reaching the combustion chamber.
If there is no fuel at the tip of the spark plug, check
for fuel ow from the fuel tank (Test 3).
3. If fuel does ow from the line, reconnect line and
check for faulty fuel pump (Test 4).
If fuel does not ow from the line, check for
clogged fuel tank vent, fuel pickup screen, shuto valve, and fuel lines.
4. If fuel does ow from the line, check for faulty
carburetor. (Refer to the "Carburetor" portions of this section.)
If fuel does not ow from the line, check for
clogged fuel line. If the fuel line is unobstructed, the fuel pump is faulty and must be replaced.
Fuel Filter
Some engines are equipped with an in-line fuel lter. Periodically inspect the lter and replace when dirty. Replacement is recommended annually or every 100 hours. Use a genuine Kohler lter.
Fuel Line
These engines use low permeation rated fuel lines, certied to comply with California and U.S. EPA evaporative emission requirements. Fuel lines that do not meet these requirements may not be used. Order replacement hose through a Kohler Service Center.
Fuel Pump
Some engines are equipped with an optional pulse fuel pump. See Figure 5-1.
Operation
The fuel pump has two internal chambers separated by a diaphragm. The air chamber is connected to the engine crankcase by a rubber hose. The fuel chamber has an inlet from the fuel tank, and an outlet to the carburetor. The inlet and outlet each have an internal, one-way check valve.
Alternating negative and positive pressures in the crankcase activate the pump. When the piston moves upward in the cylinder, negative pressure (vacuum) is created in the crankcase and in the air chamber of the pump. The diaphragm exes toward the negative pressure, and the suction draws fuel past the inlet check valve, into the fuel chamber. Downward movement of the piston causes a positive pressure in the crankcase and air chamber, pushing the diaphragm in the opposite direction, puing pressure on the fuel. The inlet check valve has now closed, so the fuel is forced past the outlet check valve, to the carburetor.
Repair
Pulse fuel pumps are not serviceable and must be replaced when faulty.
Removal
1. Disconnect the inlet, outlet, and pulse lines from the fuel pump. Mark the lines for proper reassembly.
2. Remove the hex ange screws aaching the fuel pump.
5.2
Page 33
Installation
1. Install the new fuel pump, and secure with the hex ange screws. Torque the hex ange screws to 5.9 N·m (52 in. lb.). Do not over tighten.
2. Connect the inlet, outlet, and pulse lines to their respective ings on pump. Secure with the clamps. See Figure 5-1.
Section 5
Fuel System and Governor
WARNING: Explosive Fuel
Gasoline is extremely ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or ames. Do not ll the fuel tank while the engine is hot or running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent.
Troubleshooting – Fuel System
If engine troubles are experienced that appear to be fuel system related, check the following areas before adjusting or disassembling the carburetor.
Figure 5-1. Pulse Fuel Pump.
Carburetor
These engines are equipped with a Walbro xed main jet carburetor. See Figure 5-2. The carburetors will have a low idle speed adjustment screw, and either xed idle, or a limiter cap on the idle fuel adjustment needle.
• Make sure the fuel tank is lled with clean, fresh gasoline.
• Make sure the fuel cap vent is not blocked and that it is operating properly.
• Make sure fuel is reaching the carburetor. This includes checking the fuel shut-o valve, fuel tank filter screen, in-line fuel filter, fuel lines, and fuel pump (as equipped), for restrictions or faulty components.
• Make sure the air cleaner base and carburetor are securely fastened to the engine using gaskets in good condition.
• Make sure the air cleaner element is clean, and all air cleaner components are fastened securely.
• Make sure the ignition system, governor system, exhaust system, and throle and choke controls are operating properly.
If, aer checking the items listed above, starting problems or conditions similar to those listed in the following table exist, it may be necessary to adjust or service the carburetor.
5
Figure 5-2. Carburetor.
5.3
Page 34
Section 5 Fuel System and Governor
Troubleshooting – Fuel System
Condition
1. Engine starts hard, runs roughly or stalls at idle speed.
2. Engine runs rich. (Indicated by black, sooty exhaust smoke, misfiring, loss of speed and power, governor hunting, or excessive throle opening).
3. Engine runs lean. (Indicated by misfiring, loss of speed and power, governor hunting, or excessive throle opening).
4. Fuel leaks from carburetor. 4a. Float level set too high. See Remedy 2c.
1a. Low idle fuel mixture/speed improperly adjusted. Adjust the low
idle speed screw, then adjust the low idle fuel needle.
b. Improper choke adjustment.
2a. Choke partially closed during operation. Check the choke lever/
linkage to ensure choke is operating properly.
b. Low idle fuel mixture is improperly adjusted. Adjust low idle
fuel needle.
c. Float level is set too high. With fuel bowl removed and carburetor
inverted, the exposed surface of oat must be parallel with the bowl gasket surface of the carburetor body.
d. Dirt under fuel inlet needle. Remove needle; clean needle and
seat and blow with compressed air.
e. Bowl vent or air bleeds plugged. Remove fuel bowl, low idle
fuel adjusting needle, and welch plugs. Clean vent, ports, and air
bleeds. Blow out all passages with compressed air. f. Fuel bowl gasket leaks. Remove fuel bowl and replace gasket. g. Leaky, cracked, or damaged oat. Submerge oat to check for
leaks.
3a. Low idle fuel mixture is improperly adjusted. Adjust low idle
fuel needle. b. Float level is set too low. With fuel bowl removed and carburetor
inverted, the exposed surface of oat must be parallel with the
bowl gasket surface of the carburetor body. c. Idle holes plugged; dirt in fuel delivery channels. Remove fuel
bowl, low idle fuel adjusting needle, and welch plugs. Clean
main fuel jet and all passages; blow out with compressed air.
b. Dirt under fuel inlet needle. See Remedy 2d. c. Bowl vent plugged. Remove fuel bowl and clean bowl vent. Blow
out with compressed air. d. Float is cracked or damaged. Replace oat. e. Bowl retaining screw gasket damaged. Replace gasket. f. Bowl retaining screw loose. Torque screw to specications.
Possible Cause/Probable Remedy
Carburetor Adjustment
NOTE: Carburetor adjustments should be made only
aer the engine has warmed up.
The carburetor is designed to deliver the correct fuel-to-air mixture to the engine under all operating conditions. The main fuel jet is calibrated at the factory and is not adjustable. The idle fuel adjustment needle is also set at the factory and normally does not need adjustment. If the engine is hard starting or does not operate properly, however, it may be necessary to adjust or service the carburetor.
5.4
Idle Speed (RPM) Adjustment Screw
Idle Fuel Mixture Needle
Figure 5-3. Fixed Main Jet Carburetor.
Page 35
Section 5
Fuel System and Governor
Low Idle Mixture Adjustment*
NOTE: Engines will have xed idle (no adjustment
possible) or a limiter cap on the idle fuel adjustment needle. Step 2 can only be performed within the limits allowed by the cap.
1. Start the engine and run at half throle for 5 to 10 minutes to warm up. The engine must be warm before doing step 2.
2. Low Idle Fuel Needle Seing: Place the throle into the idle or slow position.
Turn the low idle fuel adjustment needle out
(counterclockwise) from the preliminary seing until engine speed decreases (rich). Note the position of the needle.
Now turn the adjusting needle in (clockwise).
The engine speed may increase, then it will decrease as the needle is turned in (lean). Note the position of the needle.
Set the adjusting needle midway between the rich
and lean seings. See Figure 5-4.
Low Idle Speed Setting
1. Start the engine and run at half throle for 5 to 10 minutes to warm up. The engine must be warm before doing step 2.
2. Low Idle Speed Seing: Place the throle control into the idle or slow position. Set the low idle speed by turning the low idle speed adjusting screw in or out. Check the speed using a tachometer.
NOTE: The actual low idle speed depends on
the application–refer to equipment manufacturer’s recommendations. The recommended low idle speed for basic engines is 1500 RPM. To ensure best results when seing the low idle fuel needle, the low idle speed must not exceed 1500 RPM (±75 RPM).
5
Lean
Adjust to Midpoint
Rich
Figure 5-4. Optimum Low Idle Fuel Setting.
*NOTE: If the engine is equipped with a governed idle
adjustment (See Figure 5-23), the governor will compensate for speed changes due to the low idle mixture adjustment. Disable the governed idle control by backing out the governed idle adjusting screw and seing a xed idle speed using the idle speed screw on the carburetor. Make the low idle mixture adjustment and then reset the governed idle speed at the adjusting screw.
5.5
Page 36
Section 5 Fuel System and Governor
Disassembly
Throttle Lever and Shaft
Dust Seal
Throttle Plate Screw(s)
Throttle Plate
Low Idle Speed Adjusting Screw and Spring
Low Idle Fuel Adjusting Needle and Spring with Limiter Cap
Choke Lever and Shaft
Choke Return Spring
Choke Plate
Fuel Inlet Needle
Float
Float Shaft
Bowl Gasket
Fuel Bowl
Fuel Shut-off Solenoid
Figure 5-5. Carburetor - Exploded View.
1. Remove the bowl retaining screw or fuel shut-o solenoid, retaining screw gasket, and fuel bowl.
2. Remove the bowl gasket, oat sha, oat, and fuel inlet needle.
3. Do not aempt to remove the low idle fuel adjustment needle if it has a limiter cap.
Further disassembly to remove the welch plugs,
main fuel jet, throle plate and sha, and choke plate and sha is recommended only if these parts are to be cleaned or replaced.
5.6
Bowl Retaining Screw Gasket
or
Welch Plug Removal
In order to clean the idle ports and bowl vent thoroughly, remove the welch plugs covering these areas.
Use SPX Tool No. KO-1018 and the following procedure to remove the welch plugs. See Figure 5-6.
1. Pierce the welch plug with the tip of the tool.
NOTE: To prevent damage to the carburetor, do
not allow the tool to strike the carburetor body.
2. Pry out the welch plug with the tip of the tool.
Bowl Retaining Screw
Page 37
Tool No. KO1018
Section 5
Fuel System and Governor
2. The choke plate is inserted into a slot in the choke sha. Grasp the choke plate with pliers, and pull it out of the slot. See Figure 5-8.
Do Not Allow Tip to Strike Carburetor Body
Figure 5-6. Removing Welch Plug.
Main Fuel Jet Removal
The main jet is pressed into the side of the tower portion of the body. Removal is not recommended, unless a high-altitude kit is being installed, in which case the removal instructions will be included in the kit.
Fuel Inlet Seat Removal
The fuel inlet seat is pressed into the carburetor body, do not aempt to remove it. If necessary, clean it in place with aerosol carburetor cleaner.
Choke Shaft Removal
1. Because the edges of the choke plate are beveled, mark the choke plate and carburetor body, to ensure correct reassembly. See Figure 5-7.
Also note the choke plate position in the bore,
and the position of the choke lever and choke return spring.
Pierce Plug with Tip
Pry Out Plug
Welch Plug
Figure 5-8. Removing Choke Plate.
5
3. Remove the choke sha and choke return spring.
Throttle Shaft Removal
Do not aempt to remove the throle sha, as repair kits are not available. Throle sha wear is normally accompanied by corresponding wear to the carburetor body, making it impractical to aempt a cost-eective repair. Replace the entire carburetor if the throle sha is worn.
Cleaning
WARNING: Flammable Solvents!
Carburetor cleaners and solvents are extremely ammable. Keep sparks, ames, and other sources of ignition away from the area. Follow the cleaner manufacturer’s warnings and instructions on its proper and safe use. Never use gasoline as a cleaning agent.
Figure 5-7. Marking Choke Plate and Carburetor Body.
All parts should be cleaned thoroughly using a commercial carburetor cleaner. Make sure all gum deposits are removed from the following areas.
• Carburetor body and bore; especially the areas where the throle plate, choke plate and shas are seated.
• Idle fuel and idle ports in carburetor bore, main jet, bowl vent, and fuel inlet needle and seat.
• Float and oat hinge.
• Fuel bowl.
5.7
Page 38
Section 5 Fuel System and Governor
• Throle plate, choke plate, throle sha, and choke sha.
NOTE: Do not submerge the carburetor in
cleaner or solvent when plastic, ber, rubber, foam seals or gaskets are installed. The cleaner may damage these components.
Inspection
Carefully inspect all components and replace those that are worn or damaged.
• Inspect the carburetor body for cracks, holes, and other wear or damage.
• Inspect the float for cracks, holes, and missing or damaged float tabs. Check the float hinge and pin for wear or damage.
• Inspect the fuel inlet needle and seat for wear or damage.
• Inspect the tip of the low idle fuel adjustment needle for wear or grooves.
• Inspect the throle and choke sha and plate assemblies for wear or excessive play.
Repair
Always use new gaskets when servicing or reinstalling carburetors. Repair kits are available which include new gaskets and other components. Always refer to the Parts Manual for the engine being serviced to ensure the correct repair kits are ordered.
Reassembly
Choke Shaft Installation
1. Install the choke return spring to the choke sha.
Welch Plug Installation
Use SPX Tool No. KO1017 and install new plugs as follows:
1. Position the carburetor body with the welch plug cavities to the top.
2. Place a new welch plug into the cavity with the raised surface up.
3. Use the end of the tool that is about the same size as the plug and aen the plug. Do not force the plug below the surface of the cavity. See Figure 5-9.
Tool No. KO1017
Carburetor Body
Figure 5-9. Installing Welch Plugs.
4. Aer the plugs are installed, seal them with Glyptal™ (or an equivalent sealant). Allow the sealant to dry.
NOTE: If a commercial sealant is not available,
ngernail polish can be used.
Carburetor Reassembly
1. Install the low idle speed adjusting screw and spring.
New Welch Plug
2. Insert the choke sha with the return spring into the carburetor body.
3. Rotate the choke lever approximately 1/2 turn counterclockwise. Make sure the choke return spring hooks on the carburetor body.
4. Position the choke plate as marked during disassembly. Insert the choke plate into the slot in the choke sha. Make sure the choke sha is locked between the tabs on the choke plate.
5.8
2. If the low idle fuel adjusting needle contains a limiter, adjust to the midpoint within the adjustment range.
3. Insert the fuel inlet needle into the oat. Align the needle with the seat and lower the oat into the carburetor body. See Figure 5-10. Install the oat sha.
Page 39
Section 5
Fuel System and Governor
Figure 5-10. Installing Float and Fuel Inlet Needle.
4. Install the bowl gasket, fuel bowl, bowl retaining screw gasket, and bowl retaining screw or fuel solenoid.
Torque the bowl retaining screw to 5.1-6.2 N·m
(45-55 in. lb.).
Fuel Shut-off Solenoid
Many engines are equipped with a fuel shut-o solenoid installed in place of the bowl retaining screw to eliminate backring when the engine is shut down. If backring occurs on engines equipped with this solenoid, verify that the correct shutdown procedure is being used. In order for the solenoid to be eective, the engine must be running between half and full throle when the key is turned o. Next, check the baery to ensure that it is not discharged or faulty. A minimum of 7.3 volts DC is required to activate the solenoid. Also check to see that the ground lead from the carburetor body to the air cleaner base mounting screw is properly connected.
Figure 5-11. Fuel Shut-Off Solenoid.
High Altitude Operation
Operating the engine with the wrong engine configuration at a given altitude may increase its emissions and decrease fuel efficiency and performance. To ensure correct engine operation at altitudes above 1219 meters (4000 ), it may be necessary to have an authorized Kohler dealer install a special high altitude jet kit in the carburetor. If a high altitude kit has been installed, the engine must be reconverted to the original jet size, before it is operated at lower altitudes, or overheating and engine damage can result.
To obtain high altitude kit information or locate a dealer near you, call 1-800-544-2444 to nd the names of the nearest Kohler Co. Service Centers or, access our web site at: www.kohlerengines.com and click on the “Service & Dealer Locator” located in the upper right hand corner. The service center will need your engine specication number which is found on your Engine ID Label.
5
If these check out, the solenoid should be removed for bench testing. Remember to shut o the fuel supply and catch any fuel spilling from the carburetor as the solenoid is removed.
Bench test the solenoid by grounding the solenoid case and applying 12 volt DC to the spade terminal. If the plunger does not retract, the solenoid is faulty and must be replaced. Always use a new fuel bowl gasket whenever the solenoid is installed. Refer to the wiring diagram in Section 7 and connect the fuel shut-o solenoid.
Unitized Throttle and Choke Control
Some engines are equipped with a unitized throle and choke control. This assembly controls the choke and engine speed with a single lever. See Figure 5-12.
5.9
Page 40
Section 5 Fuel System and Governor
Throttle Cable Adjustment
1. Loosen the control cable clamp. See Figure 5-12.
Cable Clamp
Figure 5-12. Speed Control Bracket with Unitized Throttle/Choke Control.
2. Place the throle control lever of the equipment into the fast or high speed position. The actuating tab+ of the choke lever should be just below the end of the choke adjusting screw. See Figure 5-13.
Choke Adjustment Screw
Cold Engine
Figure 5-14. Typical Throttle/Choke Controls.
3. Early Models: Early models use a single
alignment hole to set the engine RPM. Align the hole in the throle lever with the hole in the speed control bracket by inserting a pencil or 6.35 mm (1/4 in.) drill bit. See Figure 5-15.
Alignment Hole
Figure 5-15. Alignment Hole in Speed Control Bracket and Throttle Lever. (Early Models)
Warm Engine
Figure 5-13Adjusting Unitized Throttle/Choke Control.
NOTE: The choke is placed on by moving the
throle control slightly past the fast position. If the throle control does not have a designated choke on position, be sure to leave sucient throle control travel past the fast position. This will enable the choke to be placed on. See Figure 5-14.
5.10
Later Models: Later models use a new control
assembly, identied by two opposing alignment holes (close to the throle lever pivot), instead of one. Based upon the intended high-speed (RPM) seing, throle cable adjustment must be made by matching the hole in the control lever with the correct alignment hole. Use the lower (le side) hole for high-speed seings above 3000 RPM. Use the upper (right side) hole for high-speed seings lower than 3000 RPM. Move the throle lever to align the hole in the lever with the correct hole in the control bracket. Insert a pencil or a 6.35 mm (1/4 in.) drill bit to hold in position. See Figure 5-16.
Page 41
Section 5
Fuel System and Governor
4. Pull on the outer shield of the throle control cable to remove any slack. Tighten the cable clamp securely.
Alignment Hole
Alignment Hole for 3000 RPM and Higher
Figure 5-16. Alignment Holes in Speed Control Bracket and Throttle Lever. (Later Models)
Starting an Engine Equipped with Unitized Throttle and Choke Control
1. For a Cold or Warm Engine – Place the throle/ choke control into the fast/choke on position. This will also place the choke into the on position. See Figure 5-17.
for Less Than 3000 RPM
NOTE: If the engine develops sucient speed
to disengage the starter but does not keep running (a false start), engine rotation must be allowed to come to a complete stop before aempting to restart the engine. If the starter is engaged while the ywheel is rotating, the starter pinion and ywheel ring gear may clash, resulting in damage to the starter.
If the starter does not turn the engine over, shut the starter o immediately. Do not make further aempts to start the engine until the condition is corrected. Do not jump start using another baery (refer to Baery, Section 7). See your Kohler Engine Service Dealer for trouble analysis.
5
4. For Operation – Aer the engine starts, move the throle/choke control from the fast/choke on position and set the desired engine operating speed (between the slow and fast position).
High Speed (RPM) Adjustment
The recommended maximum no-load high speed (RPM) for most engines is 3300 RPM. The actual high speed (RPM) depends on the application. Refer to the equipment manufacturer’s instructions for specic information.
Figure 5-17. Throttle Position for Starting Engine.
2. Make sure the equipment is in neutral.
3. Activate the starter switch. Release the switch as soon as the engine starts.
NOTE: Do not crank the engine continuously
for more than 10 seconds at a time. If the engine does not start, allow a 60 second cool down period between starting aempts. Failure to follow these guidelines can burn out the starter motor.
WARNING: Overspeed is Hazardous!
Do not tamper with the governor seing. Over speed is hazardous and could cause personal injury.
1. Make sure the throle cable is adjusted properly (see ‘Throle Cable Adjustment).
2. Start the engine and allow it to warm up. Place the throle control lever into the fast or high speed position. Turn the choke adjustment screw (see Figure 5-13) out/counterclockwise, so there is clearance from the choke lever, and that contact cannot occur during Step 4. See Figure 5-13.
3. Early Models: Early models use a single alignment hole to set the engine RPM. Align the hole in the throle lever with the hole in the speed control bracket by inserting a pencil or 6.35 mm (1/4 in.) drill bit. See Figure 5-15.
5.11
Page 42
Section 5 Fuel System and Governor
Later Models: Later models utilize a new design
control assembly, identied by two opposing alignment holes (close to the throle lever pivot), instead of one. Based upon the intended high speed (RPM) seing, throle cable adjustment must be made matching the hole in the control lever with the appropriate alignment hole. Use the lower (le side) hole for high-speed seings 3000 RPM and above. Use the upper (right side) hole for high-speed seings less than 3000 RPM. Move the throle lever to align the hole in the lever with the appropriate hole in the control bracket. Insert a pencil or a 6.35 mm (1/4 in) drill bit to hold in position. See Figure 5-16.
4. Loosen the speed control bracket mounting screws. Slide the bracket forward or backward, until the desired high speed (RPM) is reached. See Figure 5-18. Check the speed with a tachometer.
Choke Adjustment
This procedure must follow the High Speed Adjustment just described. If not already completed, perform that operation rst.
1. Turn the choke adjusting screw out
(counterclockwise), until it no longer contacts the choke lever.
2. Then turn it back in (clockwise), until it just
makes contact.
3. While observing the choke link, move the throle control lever to the low idle (slow) position, then back to full throle (fast). The choke link should not move as the throle moves through the normal range. If it does, back the adjusting screw out until it no longer moves.
4. Move the throle control lever to the choke position. Check if the choke has fully closed by placing your nger on the right side of the lower end of the choke lever/choke link and applying gentle pressure towards the carburetor. If the controls have been properly set, the link should not move.
Figure 5-18. Adjusting High Speed (RPM).
To increase the high speed (RPM), move the
bracket toward the carburetor.
To decrease the high speed (RPM), move the
bracket away from the carburetor.
5. Tighten the speed control bracket mounting screws. Recheck the speed with a tachometer and readjust if necessary.
Torque the mounting screws as follows:
Into new as-cast hole – 11.0 N·m (95 in. lb.). Into used hole – 7.5 N·m (65 in. lb.).
6. Adjust the choke (see Choke Adjustment which follows).
Separate Throttle and Choke Control
Some engines are equipped with separate throle and choke controls. This allows you to adjust the choke and throle controls individually.
Install Separate Control Cables
Throttle Control Installation
1. Loosen the two cable clamp screws on the speed control bracket assembly. See Figure 5-19.
2. Move the application throle control lever to the maximum full (fast) throle position, and then move it back 3/16" or 4.75 mm. Insert the cable boden wire into the throle control lever on the control plate.
3. Position the throle cable under the cable clamp.
5.12
Page 43
Choke Cable Clamp
Section 5
Fuel System and Governor
5. Pull on the outer shield of the throle control cable to remove any slack. Tighten the cable clamp securely.
Throttle Cable Clamp
Figure 5-19. Separate Choke and Throttle Cable Controls.
4. Early Models: Early models use a single
alignment hole to set the engine RPM. Align the hole in the throle lever with the hole in the speed control bracket by inserting a pencil or 6.35 mm (1/4 in.) drill bit. See Figure 5-20.
Alignment Hole
Alignment Hole
Alignment Hole for 3000 RPM and Higher
Figure 5-21. Alignment Holes in Speed Control Bracket and Throttle Lever. (Later Models)
6. Move the application throle lever to the slow position, then to full throle. Check the engine control to ensure it stops against the stop screw, which means it is properly set.
Choke Control Installation
1. Connect the choke cable boden wire to the engine choke control lever on the speed control bracket assembly.
2. Position the choke cable under the cable clamp.
3. Push/move the choke control to the o position in the application panel until it booms, then pull it back approximately 1/16 in.
for Less Than 3000 RPM
5
Figure 5-20. Alignment Hole in Speed Control Bracket and Throttle Lever. (Early Models)
Later Models: Later models utilize a new design
control assembly, identied by two opposing alignment holes (close to the throle lever pivot), instead of one. Based upon the intended high speed (RPM) seing, throle cable adjustment must be made matching the hole in the control lever with the appropriate alignment hole. Use the lower (le side) hole for high-speed seings 3000 RPM and above. Use the upper (right side) hole for high-speed seings less than 3000 RPM. Move the throle lever to align the hole in the lever with the appropriate hole in the control bracket. Insert a pencil or a 6.35 mm (1/4 in.) drill bit to hold in position. See Figure 5-21.
4. Push on the choke cable, ahead of the clamp on the engine control plate, until the choke lever stops. Do not force. Then tighten the cable clamp screw.
5. Move the choke control until it stops (on position). Check that the choke link cannot be moved towards the carburetor by applying nger pressure on the lower link/lever below the engine control plate. If the choke link moves, readjust by following steps 3 and 4.
6. Push/move the choke control in/down until it booms. The choke lever and link should be to the right at the end of its travel, with linkage free so the engine does not run on partial choke.
5.13
Page 44
Section 5 Fuel System and Governor
Starting an Engine Equipped with Separate Control Cables
1. Place the throle control midway between the slow and fast positions. Place the choke control
into the on position.
2. Start the engine.
3. For a Cold Engine – Gradually return the choke control to the o position aer the engine starts and warms up.
The engine/equipment may be operated during
the warm up period, but it may be necessary to leave the choke partially on until the engine warms up.
4. For a Warm Engine – Return choke to o position as soon as engine starts.
Changing the High Speed (RPM) on the Engines with Separate Controls (Increase or Decrease RPM)
1. Check that the governor spring and installation matches the intended high speed RPM operating range. Refer to Figure 5-27 or 5-28.
4. To ensure that the RPM has been obtained, move the throle lever to low idle/slow then back to full throle/fast position and check the RPM with a tachometer.
Setting the Low Idle RPM
1. Move the application control to slow position.
2. Using a tachometer, check the RPM. Then, using a screwdriver, turn the low idle speed screw (see Figure 5-3) inward (clockwise) to increase the RPM, and outward (counterclockwise) to lower the RPM.
Governed Idle Adjustment
A governed idle control system was supplied as a option on early engines and is standard on later model engines. The purpose of this system is to maintain a desired idle speed regardless of ambient conditions (temperature, parasitic load, etc.) that may change. The later models can be identied by the two opposing alignment holes, (adjacent from the throle lever pivot) rather than one. Based upon the intended high speed (RPM) seing, cable adjustment must be made matching the hole in the control lever with the appropriate alignment hole.
2. Start the engine, move the application throle lever to full throle/fast, and loosen the mounting screws of the main speed control bracket to allow repositioning. See Figure 5-22.
Figure 5-22. Adjusting High Speed (RPM).
3. To increase the RPM: Move the speed control
bracket, towards the carburetor. To decrease the RPM: Move the speed control bracket, away from the carburetor. Check the RPM with a tachometer and tighten screws when correct seing has been obtained. See Figure 5-19.
The system requires an additional procedure for seing the idle speed. If speed adjustments are required proceed as follows.
1. Make any necessary speed or control adjustments following the appropriate instructions already covered in this section.
2. Move the throle control to the idle position. Hold the governor lever away from the carburetor, so the throle lever is tight against the idle speed adjusting screw. Check the speed with a tachometer and adjust it to 1500-1750 RPM.
3. Release the governor lever and allow the engine to return to the governed idle speed. Check it with a tachometer against the equipment manufacturers recommended idle speed. If adjustment is necessary, use the governed idle adjusting screw on the speed control assembly (see Figure 5-23). Turn the screw clockwise to increase the governed idle speed and counterclockwise to decrease it.
5.14
Page 45
Governed Idle Adjusting Screw
Figure 5-23. Location of Governed Idle Adjusting Screw.
Governor
These engines are equipped with a centrifugal yweight mechanical governor, designed to hold the engine speed constant under changing load conditions. The governor gear/yweight mechanism is mounted on the closure plate in the crankcase, and is driven o a gear on the cranksha.
NOTE: Flyweights must be installed perpendicular
to the nylon gear as shown. Improper installation of the yweights may cause damage to the governor gear. See Figure 5-24.
Section 5
Fuel System and Governor
The governor lever is clamped on the protruding end of the sha and connected with linkage to the throle lever on the carburetor, so any rotation of the sha causes corresponding movement of the throle plate.
When the engine is at rest, and the throle is in the fast position, the tension of the governor spring holds the throle plate open. When the engine is operating (the governor gear assembly is rotating), the force applied by the regulating pin against the cross sha tends to close the throle plate. The governor spring tension and the force applied by the regulating pin are in equilibrium during operation, holding the engine speed constant.
When load is applied and the engine speed (and governor gear speed) decreases, the governor spring tension moves the governor arm to open the throle plate wider. This allows more fuel into the engine; increasing engine speed. This action takes place very rapidly, so a reduction in speed is hardly noticed. As the speed reaches the governed seing, the governor spring tension and the force applied by the regulating pin will again be in equilibrium. This maintains the engine speed at a relatively constant level.
The governed speed seing is determined by the position of the throle control. It can be variable or constant, depending on the application.
5
Flyweights
Nylon Gear
Figure 5-24. Governor Gear/Flyweight Assembly.
Operation
As the governor gear rotates, centrifugal force causes the flyweights to move outward as speed increases. As the flyweights move outward, they cause the regulating pin to move outward.
The regulating pin contacts the tab on the cross sha, causing the sha to rotate. One end of the cross sha protrudes through the side of the crankcase.
Initial Adjustment
Make this initial adjustment whenever the governor arm is loosened or removed from the cross sha. To ensure proper seing, make sure the throle linkage is connected to the governor arm and the throle lever on the carburetor. See Figures 5-25 and 5-26.
1. Move the governor lever toward the carburetor
(wide open throle). Do not apply excess force exing or distorting the throle link.
2. Grasp the cross sha with pliers, and turn the
shacounterclockwise as far as it will go, then tighten the hex nut. Torque the hex nut to
7.0-8.5 N·m (60-75 in. lb.).
5.15
Page 46
Section 5 Fuel System and Governor
Figure 5-25. Governor Adjustment.
Governor Sensitivity Adjustment
Governor sensitivity is adjusted by repositioning the governor spring in the holes in the governor lever. If speed surging occurs with a change in load, the governor is set too sensitive. If a big drop in speed occurs when a normal load is applied, the governor should be set for greater sensitivity.
The desired high speed seing (RPM) will determine the governor spring position in the governor lever and the throle lever, as well as the spring used. See Figure 5-27 and 5-28.
Throttle Lever
1
2
3
Governor Lever
1
2
3
Figure 5-26. Tightening Governor Lever Nut.
Single Alignment Hole
High Speed
RPM
 ;
 ;
  ;
Figure 5-27. Early Style Governor Spring Location Chart.
5.16
Governed
Idle RPM
Governed
Lever Hole No.
Throttle Lever
Hole No.
White
Spring
Green
Spring
Black
Spring
Page 47
Section 5
Fuel System and Governor
Single Hole
2
1
2
Throttle Lever
/HVVWKDQ530 6LQJOH+ROH ; %
/HVVWKDQ530 6LQJOH+ROH ; $
Figure 5-28. Later Style Governor Spring Location Chart.
3
Governor Lever (Single Hole)
High Speed
RPM
Governed
Idle RPM
Governor Lever (Multiple Hole)
Governed
Lever Hole No.
3
1
Alignment Hole for 3000 RPM and Higher
Throttle Lever
Hole No.
A
Red
Spring
B
Alignment Hole for Less Than 3000 RPM
Alignment
Hole
5
5.17
Page 48
Section 5 Fuel System and Governor
5.18
Page 49
Section 6
Lubrication System
Oil Recommendations
Using the proper type and weight of oil in the crankcase is extremely important. So is checking oil daily and changing oil regularly. Failure to use the correct oil, or using dirty oil, causes premature engine wear and failure.
Oil Type
Use high-quality detergent oil of API (American Petroleum Institute) service class SJ or higher. Select
the viscosity based on the air temperature at the time of operation as shown in the following table.
RECOMMENDED SAE VISCOSITY GRADES
10W-30
**
5W-20, 5W-30
*
Section 6
Lubrication System
V
R
I
C
E
S
I
P
A
SAE
10W-30
Figure 6-2. Oil Container Logo.
Check Oil Level
The importance of checking and maintaining the proper oil level in the crankcase cannot be overemphasized. Check oil BEFORE EACH USE as follows:
E
S
J
6
Kohler 10W-30
°F -20 0 20 32 40 60 80 100
°C -30 -20 -10 0 10 20 30 40
TEMPERATURE RANGE EXPECTED BEFORE NEXT OIL CHANGE
* Use of synthetic oil having 5W-20 or 5W-30 rating is acceptable,
up to 4°C (40°F)
** Synthetic oils will provide better starting in extreme cold below
23°C (-10°F)
Figure 6-1. Viscosity Grades Table.
NOTE: Using other than service class SG, SH, SJ or
higher oil or extending oil change intervals longer than recommended can cause engine damage.
NOTE: Synthetic oils meeting the listed
classifications may be used with oil changes performed at the recommended intervals. However to allow piston rings to properly seat, a new or rebuilt engine should be operated for at least 50 hours using standard petroleum based oil before switching to synthetic oil.
A logo or symbol on oil containers identies the API service class and SAE viscosity grade. See Figure 6-2.
1. Make sure the engine is stopped, level, and is cool so the oil has had time to drain into the sump.
2. To keep dirt, grass clippings, etc., out of the engine, clean the area around the oil ll cap/ dipstick before removing it.
3. Remove the oil ll cap/dipstick; wipe oil o. See Figure 6-3. Reinsert the dipstick into the tube and fully seat the dipstick in the tube. See Figure 6-4.
Figure 6-3. Removing Dipstick.
6.1
Page 50
Section 6 Lubrication System
Oil Filter
Oil Drain Plug
Figure 6-4. Dipstick Seated.
4. Remove the dipstick and check the oil level. The oil level should be up to, but not over the ‘‘F’’ mark on the dipstick. See Figure 6-5.
Operating Range
Figure 6-5. Oil Level Dipstick.
5. If the level is low, add oil of the proper type, up to the ‘‘F’’ mark on the dipstick. Always check the level with the dipstick before adding more oil.
NOTE: To prevent extensive engine wear or
damage, always maintain the proper oil level in the crankcase. Never operate the engine with the oil level below the ‘‘L’’ mark or over the ‘‘F’’ mark on the dipstick.
Change Oil and Oil Filter
Change the oil and oil lter annually or every 100 hours of operation. Change the oil and oil lter while
the engine is still warm. The oil will ow more freely and carry away more impurities. Make sure the engine is level when lling or checking oil. Change the oil and lter as follows (see Figure 6-6). Always use a genuine Kohler oil lter.
Figure 6-6. Oil Drain Plug, Oil Filter.
1. To keep dirt, grass clipping, etc., out of the engine, clean the area around the oil ll cap/ dipstick before removing it.
2. Remove the drain plug and oil ll cap/dipstick. Be sure to allow ample time for complete drainage.
3. Remove the old lter and wipe o the mounting pad.
4. Reinstall the oil drain plug and torque to 14 N·m (125 in. lb.).
5. Place the new replacement lter in a shallow pan with the open end up. Pour new oil of the proper type, in through the threaded center hole. Stop pouring when the oil reaches the boom of the threads. Allow a minute or two for the oil to be absorbed by the lter material.
6. Apply a thin lm of clean oil to the rubber gasket on the new lter.
7. Install the new oil lter to the lter adapter or oil cooler. Refer to instructions on the oil lter for proper installation.
8. Fill the crankcase with new oil of the proper type, to the “F” mark on the dipstick.
9. Reinstall the oil ll cap/dipstick and push rmly into place.
10. Test run the engine to check for leaks. Stop the engine, allow a minute for the oil to drain down, and recheck the level on the dipstick. Add more oil, as necessary, so the oil level is up to but not over the “F” mark.
6.2
Page 51
Section 6
Lubrication System
NOTE: To prevent extensive engine wear or
damage, always maintain the proper oil level in the crankcase. Never operate the engine with the oil level below the ‘‘L’’ mark or over the ‘‘F’’ mark on the dipstick.
Full-Pressure Lubrication System
Operation
This engine uses a full-pressure lubrication system to deliver oil for internal lubrication. A cam driven, high eciency Gerotor™ oil pump located in the crankcase maintains proper oil ow and oil pressure even at low speeds and high operating temperatures. Oil is supplied from the pump via two circuits to the cranksha main bearings, cranksha, connecting rod bearing surfaces, cam gears, and axis shas. An integral pressure relief valve within the oil pump limits the maximum pressure of the system.
For a cold engine at start up, the oil pressure can go up to 20-25 psi. For a warm (normal operating temperature) engine at idle speed, the oil pressure can go down to 5 psi.
Service
The oil pump rotors typically require no servicing, if normal maintenance is performed as outlined in Section 1.
The closure plate must be removed for access to the oil pump and the rotors. Refer to the Disassembly and Reassembly, Sections (8 and 10), for removal and reinstallation procedures.
Oil Filter
These engines are equipped with a full-ow oil lter. See Figure 6-8.
The oil lter helps remove sludge and other combustion by-products from the oil. It also extends the oil change interval and cools the oil.
Oil Filter
Figure 6-8. Oil Filter Location.
Oil Sentry™
Some engines are equipped with an optional Oil Sentry™ switch. This switch is designed to prevent the engine from starting in a low oil or no oil condition. The 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.
Operation
The pressure switch is designed to break contact as the oil pressure increases and make contact as the oil pressure decreases. At oil pressure above approximately 2 to 5 psi, the switch contacts open. At oil pressures below approximately 2 to 5 psi, the switch contacts close.
6
Figure 6-7. Oil Pump on Intake Cam Shaft (Gerotors Removed from Pump Housing).
On vehicular applications (lawn tractors, mowers, etc.), the pressure switch can be used to activate a low oil warning light. On stationary or unaended applications, the pressure switch can be used to ground the ignition module to stop the engine.
NOTE: Oil Sentry™ is not a substitute for checking
the oil level BEFORE EACH USE. Make sure the oil level is maintained up to the ‘‘F’’ mark on the dipstick. See Figure 6-5.
6.3
Page 52
Section 6 Lubrication System
Installation
The pressure switch is installed into the center oil galley of the lter adapter casting on the closure plate. Based on the application an elbow adapter may also be used. See Figure 6-9. On engines not equipped with
Oil Sentry
, the oil galley is sealed with a 1/8" pipe
plug or completely sealed.
Oil Sentry (External)
Oil Sentry Blower Housing)
(Behind
Figure 6-9. Oil Sentry™ Pressure Switch Locations.
To install the Oil Sentry™ switch:
1. Remove and discard the pipe plug from the center passage of oil lter mounting pad.
2. Apply pipe sealant with Teon® (Loctite® No. 59241 or equivalent) to the threads of the 90° adapter (if used), and the Oil Sentry™ switch.
1. Connect the continuity tester across the blade terminal and the metal case of the switch. With 0 psi pressure applied to the switch, the tester should indicate continuity (switch closed).
2. Gradually increase the pressure to the switch. The tester should indicate a change to no continuity (switch open) as the pressure increases through the range of 2.0/5.0 psi.
The switch should remain open as the pressure is
increased to 90 psi maximum.
3. Gradually decrease the pressure to the switch. The tester should indicate a change to continuity (switch closed) as the pressure decreases through the range of 2.0/5.0 psi; approaching 0 psi.
If the switch does not operate as specied,
replace the switch.
Testing Oil Pressure
On some models the engine oil pressure can be tested using an oil pressure tester. Follow the instructions included with the tester. The pressure can be tested by removing the oil lter and installing the tester adapter on the mounting pad, or by removing the Oil Sentry pressure switch (or pipe plug) and threading the tester hose directly into the mounting hole. See Figure 6-10.
3. Install the adapter (if used), and carefully tighten it to the intended position. Do not over tighten or damage the adapter.
4. Install the switch into the adapter or center passage. Torque the switch to 4.5-5.0 N·m (40-45 in. lb.).
5. Connect the lead to the terminal on the Oil Sentry™ switch.
Testing the Oil Sentry™ Switch
The Oil Sentry™ pressure monitor is a normally closed switch. It is calibrated to open (break contact) with increasing pressure and close (make contact) with decreasing pressure within the range of 2.0/5.0 psi.
Compressed air, a pressure regulator, pressure gauge, and a continuity tester are required to test the switch.
6.4
Locations For Tester
Figure 6-10. Tester Locations (Some Models).
Page 53
Section 7
Electrical System and Components
Section 7
Electrical System and Components
This section covers the operation, service, and repair of the electrical system and electrical system components.
Major electrical systems and components covered in this section include the ignition system, baery, baery charging systems, electric starter, and optional Oil Sentry™ oil level pressure switch.
WARNING: Electrical Shock
Never touch electrical wires or components while the engine is running. They can be sources of electrical shock.
Spark Plug
Engine misre or starting problems are oen caused by a spark plug that is in poor condition or has an improper gap seing.
The engine is equipped with the following spark plug:
Type: Champion® RC12YC or QC12YC (RFI Compliant)
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.)
Spark Plug Service
Annually or every 100 hours of operation, remove the spark plug. Check its condition, and reset the gap or replace with a new plug as necessary. Spark plug replacement is recommended at 500 hours.
1. Before removing the spark plug, clean the area around the base of the plug to keep dirt and debris out of the engine. Due to the deep recess around the spark plug, blowing out the cavity with compressed air is usually the most eective method for cleaning. The spark plug is most accessible when the blower housing is removed for cleaning.
2. Remove the plug and check its condition. Replace the plug if worn or reuse is questionable.
NOTE: Do not clean the spark plug in a machine
using abrasive grit. Some grit could remain in the spark plug and enter the engine, causing extensive wear and damage.
3. Check the gap using a wire feeler gauge. Adjust the gap by carefully bending the ground electrode. Gap plugs to 0.76 mm (0.030 in.). See Figure 7-1.
Wire Gauge
Spark Plug
0.76 mm
Ground Electrode
Figure 7-1. Servicing Spark Plug.
4. Reinstall the spark plug into the cylinder head.
Torque the spark plug to 24-30 N·m (18-22 . lb.).
5. Reconnect the spark plug lead and reinstall the blower housing, if removed previously. Torque the blower housing screws to 7.7 N·m (68.3 in. lb.).
(0.030 in. ) Gap
7
7.1
Page 54
Section 7 Electrical System and Components
Inspection
Inspect the spark plug as soon as it is removed from the cylinder head. The deposits on the tip are an indication of the general condition of the piston rings, valves, and carburetor.
Normal and fouled plugs are shown in the following photos.
Chalky White Deposits: Chalky white colored deposits indicate overheating. This condition is usually accompanied by excessive gap erosion. A clogged grass screen, clogged cooling ns, and lean carburetion are some causes of overheating.
Normal: A plug taken from an engine operating under normal conditions will have light tan or gray colored deposits. If the center electrode is not worn, a plug in this condition could be regapped and reused.
Worn: On a worn plug, the center electrode will be rounded and the gap will be eroded .010" or more than the correct gap. Replace a worn spark plug immediately.
Carbon Fouled: So, sooty, black deposits indicate incomplete combustion. Incomplete combustion is usually caused by over-rich carburetion, weak ignition, or poor compression.
7.2
Wet Fouled: A wet plug is caused by excess fuel, or oil in the combustion chamber. Excess fuel could be caused by operating the engine with too much choke or a dirty air lter. Oil in the combustion chamber is usually caused by worn piston rings or valve guides.
Page 55
Electronic CD Ignition System
Air Gap
0.203/0.305 mm (0.008-0.012 in.)
Electrical System and Components
Ignition Module
Spark Plug Boot
Spark Plug
Section 7
Spark Plug Terminal (C)
Flywheel
Kill Switch or Off Position of Key Switch
Figure 7-2. Electronic CD Ignition System.
These engines are equipped with a dependable electronic, capacitive discharge (CD) ignition system. The system consists of the following components:
• A magnet assembly which is permanently axed to the ywheel.
• An electronic, capacitive discharge ignition module which mounts on the engine crankcase.
Magnet
Lamination (A)
• A spark plug.
• A kill switch (or key switch), which grounds the module to stop the engine.
Kill Terminal (B)
7
7.3
Page 56
Section 7 Electrical System and Components
D1
SCS
L1
L2
Figure 7-3. Capacitive Discharge Ignition Module.
Operation
As the flywheel rotates, and the magnet passes the ignition module, the magnetic eld induces current in the input coil (L1). The current pulse is rectied by a diode (D1) and charges a high-voltage capacitor (C1). As the magnet completes its pass, it induces current in a small triggering coil (L2), which turns on the semiconductor switch (SCS). With the switch on, the charged capacitor is directly connected to the primary winding (P) of the transformer (T1). As the capacitor discharges through the primary, the current initiates a fast-rising ux eld in the transformer core. The ux field induces a high voltage in the secondary winding (S) of the transformer. The high voltage pulse is delivered to the spark plug, where it arcs across the electrode gap and ignites the fuel-air mixture in the combustion chamber.
Troubleshooting and Testing CD Ignition Systems
The CD ignition system is designed to be trouble free for the life of the engine. Other than periodically checking/replacing the spark plug, no maintenance or timing adjustment is necessary or possible. The ignition module automatically controls the timing of the spark. Mechanical systems do occasionally fail or break down, however, so the following troubleshooting information is provided to help systematically determine the cause of a reported problem.
Reported ignition problems are most oen due to poor or loose connections. Before beginning the test procedure check all external wiring, including ground leads for wiring harness and rectier-regulator (if so equipped). Be certain all ignition-related wires are connected, including the spark plug lead, and all terminal connections t snugly. Make sure the ignition switch is in the run position.
C1
NOTE: The CD ignition systems are sensitive to
Preliminary Test
To be certain the reported problem is in the engine ignition system, it should be isolated from the unit, as follows.
1. Locate the plug connectors where the wiring
a. If the problem is gone, the electrical system
b. If the problem persists, continue with the
T1
Spark Plug
P
excessive load on the kill lead. Customer complaints of hard starting, low power, or misfire under load may be due to excessive draw on the kill circuit. Disconnect any auxiliary kill wires or safety switches connected to the kill circuit and operate the engine to determine if the reported problem is gone.
harnesses from the engine and unit are joined. Separate the connectors and separate the white kill lead from the engine connector. Rejoin the connectors and position or insulate the kill lead terminal, so it cannot touch ground. Try to start the engine to verify whether the reported problem is still present.
on the unit is suspect. Check the key switch, wires, connections, safety interlocks, etc.
following troubleshooting procedure. Leave the kill lead isolated until all testing is completed.
S
7.4
Page 57
Electrical System and Components
CD Ignition System Troubleshooting Guide
7KHIROORZLQJJXLGHZLOOKHOSORFDWHDQGFRUUHFWLJQLWLRQV\VWHPSUREOHPV
Problem Test
1. Make sure the spark plug lead is connected to the spark plug.
Engine
Will Not
Start
2. Check the condition of spark plug. Make sure gap is set to 0.76 mm (0.030 in.).
3. a. Test for spark with ignition tester (See Section 2).
Disconnect spark plug lead and connect it to
the post terminal of the tester. See Figure 7-4. Connect the clip to a good ground, not the spark plug.
NOTE: To maintain engine speeds normally
obtained during cranking, do not remove the engine spark plug.
b. Make sure the engine ignition switch,
kill switch, or key switch is in the ‘‘run’’ position.
c. Crank the engine (minimum speed 500
RPM), and observe the tester. Visible and audible sparks should be produced.
2. If plug is in good condition, check/adjust gap and reinstall.
3. If visible and audible sparks are produced, the ignition module is OK.
If visible and audible sparks are not
produced:
a. Make sure the engine ignition switch,
b. Check wires and terminals of ignition
c. If wires and terminals are OK, the
Section 7
Conclusion
kill switch, or key switch is in the ‘‘run’’ position.
module and other components for accidental grounding and damaged insulation.
ignition module is probably faulty and should be replaced. Test module further using an ohmmeter (Test 4).
4. Measure the resistance of module secondary using an ohmmeter (see Figures 7-2 and 7-5):
Zero ohmmeter before testing. Connect
one ohmmeter lead to laminations (A). Connect the other lead to the spark plug terminal (C) of high-tension lead. With the ohmmeter leads connected in this manner, the resistance of secondary should be 7,900 to 18,400 ohms.
NOTE: This test cannot be performed
unless module has been red at least once.
4. If the resistance is low or 0 ohms, the
module secondary is shorted. Replace the module.*
If the resistance is high or innity ohms,
the module secondary is open. Replace the module.*
If the resistance is within the specied
range, the module secondary is OK.
*Refer to the Disassembly and Reassembly
Sections for complete ignition module removal and installation procedures.
7
Figure 7-4. Ignition Tester (See Section 2).
Figure 7-5. Testing CD Ignition Module Secondary.
7.5
Page 58
Section 7 Electrical System and Components
Battery
A 12 volt baery with a minimum current rating of 250 cold cranking amps is recommended. The actual cold cranking amp requirement depends on engine size, application and starting temperatures. As temperatures decrease, cranking requirements increase but baery capacity shrinks. Refer to the operating instructions of the equipment this engine powers for specic baery requirements.
If the baery charge is not sufficient to crank the engine, recharge the baery. Do not jump start using another baery.
Battery Charging
WARNING: Explosive Gases!
Baeries produce explosive hydrogen gas while being charged. To prevent a re or explosion, charge baeries only in well ventilated areas. Keep sparks, open ames, and other sources of ignition away from the baery at all times. Keep baeries out of the reach of children. Remove all jewelry when servicing baeries.
Before disconnecting the negative (-) ground cable, make sure all switches are OFF. If ON, a spark will occur at the ground cable terminal, which could cause an explosion if hydrogen gas or gasoline vapors are present.
Battery Maintenance
Regular maintenance will ensure the baery will accept and hold a charge.
1. Regularly check the level of electrolyte. Add distilled water as necessary to maintain the recommended level.
Battery Test
Test the baery voltage by connecting a DC voltmeter across the baery terminals and cranking the engine. If the baery drops below 9 volts while cranking, the baery is discharged or faulty. Refer to Figure 7-6.
DC Voltmeter
Battery
Figure 7-6. Checking Battery Voltage.
Electrical Systems Wiring Diagrams and Battery Charging Systems
Most engines are equipped with either a 9 or 15 amp, regulated baery charging system. Some have a 3 amp, regulated system with a 70 wa lighting circuit.
Refer to the following wiring diagrams and troubleshooting guides to test and service the system.
NOTE: Observe the following guidelines to
prevent damage to the electrical system and components.
1. Make sure the baery polarity is correct. A negative (-) ground system is used.
NOTE: Do not overll the baery. Poor
performance or early failure due to loss of electrolyte will result.
2. Keep the cables, terminals, and external surfaces of the baery clean. A build-up of corrosive acid or grime on the external surfaces can self­discharge the baery. Self-discharging happens rapidly when moisture is present.
3. Wash the cables, terminals, and external surfaces with a baking soda and water solution. Rinse thoroughly with clear water.
NOTE: Do not allow the baking soda solution to
enter the cells of the baery, as this will destroy the electrolyte.
7.6
2. Disconnect the baery cables (negative (-) cable rst), before doing electric welding on the equipment powered by the engine.
3. Prevent the stator leads from touching or shorting while the engine is running. This could damage the stator.
Page 59
Lighting Lead (Yellow)
Lighting Stator
Charging Lead (Black)
Figure 7-7. 3 Amp/70 Watt Stator.
Section 7
Electrical System and Components
3 Amp Charging Stator
Diode
Ground-To­Kill Lead
A
M
Key Switch
Optional Oil Sentry Shutdown
Optional Fuse
Optional Oil Sentry Switch (Indicator Light)
R
S
B
TM
TM
Engine Connector
White
AC
B+
AC
Regulator­Rectier
Violet
Green
Stator
Flywheel
Ignition Module
Spark Plug
7
(Red)
Optional Fuel Solenoid
Battery
Figure 7-8. 3 amp Regulated Battery Charging System/70 Watt Lighting.
Starter Solenoid
Optional Oil Sentry™ Switch (Shutdown or
Indicator) Bendix Starter
7.7
Page 60
Section 7 Electrical System and Components
Troubleshooting Guide 3 Amp Battery Charging System With 70 Watt Lighting Stator
NOTE: Zero ohmmeteres on each scale to ensure accurate readings. Voltage tests should be made with engine
running at full throle - no load. Baery must be fully charged.
Problem Test
1. With engine running in the fast seing, measure voltage across baery terminals using a DC voltmeter.
2. Remove connector from rectier-regulator. With engine running in the fast position, measure AC voltage across stator leads using an AC voltmeter.
3. With charging lead disconnected from baery and engine stopped, measure resistance from charging lead to ground
No
Charge
To
Battery
using an ohmmeter. Note reading.
Reverse the leads and measure resistance
again.
In one direction, the resistance should
be innity ohms (open circuit). With the leads reversed, some resistance should be measured (about midscale on Rx1 range).
4. Cut the sleeving on the charging lead to expose the diode connections.
Measure the resistance from the stator side
of diode to ground using an ohmmeter.
Conclusion
1. If voltage is more than 12.5 volts, charging
system is OK.
If voltage is 12.5 volts or less, the stator or
diode are probably faulty. Test the stator and diode (Test 2, 3, and 4).
2. If voltage is 20 volts or more, stator
winding is OK.
If voltage is less than 20 volts, test stator
using an ohmmeter (Tests 3 and 4).
3. If resistance is low in both directions, the
diode is shorted. Replace the diode.
If resistance is high in both directions, the
diode or stator winding is open. (Use
Test 4).
4. If resistance is approximately 0.5 ohms,
stator winding is OK, diode is open. Replace diode.
If resistance is 0 ohms, stator winding is
shorted. Replace stator.
1. Make sure lights are not burned out.
2. Disconnect the lighting lead from the wiring harness.
No
Lights
7.8
With engine running at in the fast seing,
measure voltage from lighting lead to ground using an AC voltmeter.
3. With engine stopped, measure the resistance of stator from lighting lead to ground using an ohmmeter.
If resistance is innity ohms, stator
winding or lead is open. Replace stator.
1. Replace burned out lights.
2. If voltage is 13 volts or more, stator is OK.
Check for loose connections or shorts in wiring harness.
If voltage is less than 13 volts, test stator
using an ohmmeter (Test 3).
3. If resistance is approximately 0.2 ohms,
stator is OK.
If resistance is 0 ohms, stator is shorted.
Replace stator.
If resistance is innity ohms, stator or
lighting lead is open. Replace stator.
Page 61
Section 7
Electrical System and Components
Troubleshooting Guide 3 Amp/70 Watt Braking Stator
NOTE: Zero ohmmeteres on each scale to ensure accurate readings. Voltage tests should be made with engine
running at full throle - no load. Baery must be fully charged.
Problem
No
Charge
To
Battery
Test
1. With engine running in the fast seing, measure voltage across baery
terminals using a DC voltmeter.
2. Remove connector from rectier-regulator. With engine running in the fast position, measure AC voltage across stator leads using an AC voltmeter.
3. With charging lead disconnected from baery and engine stopped, measure resistance from charging lead to ground using an ohmmeter. Note reading.
Reverse the leads and measure resistance
again.
In one direction, the resistance should
be innity ohms (open circuit). With the leads reversed, some resistance should be measured (about midscale on Rx1 range).
4. Disconnect the lighting lead (yellow) from the wiring harness.
Measure the resistance from the lighting
lead to ground using an ohmmeter.
Conclusion
1. If voltage is more than 12.5 volts, charging
system is OK.
If voltage is 12.5 volts or less, the stator or
diode are probably faulty. Test the stator and diode (Test 2, 3, and 4).
2. If voltage is 5 volts or more, stator winding
is OK.
If voltage is less than 5 volts, test stator
using an ohmmeter (Tests 3 and 4).
3. If resistance is low in both directions, the
diode is shorted. Replace the diode.
If resistance is high in both directions, the
diode or stator winding is open.
(Use Test 4.)
7
4. If resistance is approximately 0.15 ohms,
stator winding is OK, diode is open. Replace diode.
If resistance is 0 ohms, stator winding is
shorted. Replace stator.
1. Make sure lights are not burned out.
2. Disconnect the lighting lead (yellow) from the wiring harness.
No
Lights
With engine running in the fast seing,
measure voltage from lighting lead to ground using an AC voltmeter.
3. With engine stopped, measure the resistance of stator from lighting lead to ground using an ohmmeter.
If resistance is innity ohms, stator winding
or lead is open. Replace stator.
1. Replace burned out lights.
2. If voltage is 13 volts or more, stator is OK.
Check for loose connections or shorts in wiring harness.
If voltage is less than 13 volts, test stator
using an ohmmeter (Test 3).
3. If resistance is approximately 0.15 ohms,
stator is OK.
If resistance is 0 ohms, stator is shorted.
Replace stator.
If resistance is innity ohms, stator or
lighting lead is open. Replace stator.
7.9
Page 62
Section 7 Electrical System and Components
Troubleshooting Guide 3 amp/70 Watt Braking Stator (Continued)
Problem
No
Lights
Or
Battery
Charging
(Braking
System
Test)
1. Make sure lights are not burned out.
2. Disconnect the braking lead (green) from the wiring harness.
With engine running in the fast seing,
measure voltage from braking lead to ground using an AC voltmeter.
3. With the engine stopped, measure the resistance from braking lead to ground using an ohmmeter.
Test
1. Replace burned out lights.
2. If voltage is 35 volts or more, stator
is OK. Circuitry on unit that grounds braking lead is shorted.
If voltage is less than 35 volts, test stator
using an ohmmeter (Test 3).
3. If resistance is approximately
0.2-0.4 ohms, stator is OK.
If resistance is 0 ohms, stator is shorted.
Replace stator.
If resistance is innity ohms, stator or
lighting lead is open. Replace stator.
Conclusion
7.10
Page 63
Battery Charging System 9 or 15 amp
Section 7
Electrical System and Components
Ground-to-Kill Lead
A
R
M
Key Switch
Optional Fuse
_
Battery
+
Starter Solenoid
White
S
B
Engine Connector
Optional Oil Sentry™ Indicator Light
AC
AC
Violet
Green
B+
Rectier­Regulator
Green
Stator
Flywheel
Ignition Module
Spark Plug
Red
Optional Fuel Solenoid
Optional Oil Sentry™ Switch (Shutdown)
7
Optional Oil Sentry™
Bendix Starter
Switch (Indicator)
Figure 7-9. Regulated Battery Charging System, 9 or 15 amp.
7.11
Page 64
Section 7 Electrical System and Components
Rectifier-Regulator
AC
AC
Figure 7-10. 9 or 15 amp Stator and Rectifier-Regulator.
DC Volt Meter
(-)
B+
9 or 15 Amp Stator
Rectifier-Regulator
AC
B+
AC
Flywheel Stator
Battery
Figure 7-11. Proper Connection to Test 9 or 15 amp Charging System.
7.12
Ammeter
Page 65
Section 7
Electrical System and Components
Troubleshooting Guide 9 or 15 amp Regulated Battery Charging System
NOTE: Zero ohmmeters on each scale to ensure accurate readings. Voltage tests should be made with engine
running at full throle - no load. The baery must be fully charged.
Problem Test Conclusion
1. If voltage is 13.8-14.7 and charge rate increases when load is applied, the charging system is OK and baery was fully charged.
If voltage is less than 13.8 or charge rate does
not increase when load is applied, test stator (Tests 2 and 3).
2. If voltage is 28 volts or more, stator is OK. Rectier-regulator is probably faulty. Verify with Rectier-regulator tester KO3221.
If voltage is less than 28 volts, stator is probably
faulty and should be replaced. Test stator further using an ohmmeter (Test 3).
3a. If resistance is 0.1/0.2 ohms, the stator is OK.
If the resistance is innity ohms, stator is open.
Replace stator.
No
Charge
To
Battery
1. Trace B+ lead from rectier-regulator to key switch, or other accessible connection. Disconnect it from switch or connection. Connect an ammeter from loose end of B+ lead to positive terminal of baery. Connect DC voltmeter from loose end of B+ lead to negative terminal of baery. See Figure 7-11. With engine running in the fast position, read voltage on voltmeter.
If voltage is 13.8 volts or more, place a
minimum load of 5 amps* on baery to reduce voltage. Observe ammeter.
*NOTE: Turn on lights, if 60 was or more.
Or place a 2.5 ohm, 100 wa resistor across baery terminals.
2. Remove connector from rectier-regulator. With engine running in the fast position, measure AC voltage across stator leads using an AC voltmeter.
3a. With engine stopped, measure the resistance
across stator leads using an ohmmeter.
7
Battery
Continuously
Charges At
High Rate
3b. With the engine stopped, measure the
resistance from each stator lead to ground using an ohmmeter.
1. Perform same test as step 1 above.
3b. If the resistance is innity ohms (no continuity),
the stator is OK (not shorted to ground).
If resistance (or continuity) is measured, the
stator is shorted to ground. Replace stator.
1. If the voltage is 14.7 volts or less the charging
system is OK. The baery is unable to hold a charge. Service baery or replace as necessary.
If voltage is more than 14.7 volts, the rectifier-regulator is faulty. Replace rectifier-regulator.
7.13
Page 66
Section 7 Electrical System and Components
Blade Stop Stator Brake Circuit
The blade stop stator brake circuit is provided as a safety feature to ensure the application can meet ANSI (American National Standards Institute) application blade stop requirements.
The circuit is activated if the operator gets o of the seat of the application while mower blade system is activated or in certain reverse mow conditions.
The circuit is activated by taking the ignition shutdown (kill) lead to ground. This action turns on the stator-brake relay which shorts the charging AC stator leads to produce a magnetic eld that will counter or resist the rotation of the ywheel. This added resistance to rotation decreases the amount of time it takes for the application deck blades to come to a full stop.
As the Kohler blade stop stator brake circuit oen is operated in conjunction with other application circuits, the relay in the Kohler circuit is specially congured with a 680 ohm resistor in parallel with the relay coil. This is done to negate transient voltage signals that would be normally created by interrupting the relay current once the relay has been activated. Therefore, relay replacement must only be made with the properly identied relay.
12V Switched Power
Reverse Mow Module (OEM Supplied)
TRIAC
Stator Brake Relay Coil
Engine
NO
PTO
NC
90 Ω
Brake
680 Ω
Kill
Key Switch
CDI Ignition
Figure 7-12. Blade Stop Stator Brake Circuit Wiring Diagram.
7.14
NO
NC
Seat
Page 67
Stator Assembly
Wiring Harness
Stator leads to Rectifier-Regulator
Electrical System and Components
Insert stator leads into connector slots shown either orientation is acceptable
Wiring Harness
Insert relay into harness connector as shown
Wire Tie (Black)
Center slot is empty
Position connector with relay approximately as shown and attach to starter with wire tie
Section 7
Push Wing Mount (Black)
Figure 7-13. Stator Brake and Relay Harness Connections.
Troubleshooting Stator Brake System
Problems that could occur with the Kohler portion circuit generally could be caused by two component failures or an incorrect relay replacement, which will create the following conditions:
Dead Battery The brake relay has failed and is keeping the stator shorted, so no charge current can be passed from the rectier-regulator to the baery, eventually allowing the baery to discharge.
Test
Check baery voltage using a test meter with the application o and then while the application is operating at maximum speed. The baery voltage should increase from the engine o condition to the engine full speed condition.
If it does not, shut down the engine, remove the relay from its socket and re-test at full engine speed.
If the baery voltage does not increase with the engine operating, the problem is likely not with the stator brake relay.
Engine will crank but will not start
The brake stator relay is interacting with the application safeties or the reverse mow electronics, preventing normal engine start up.
Test
Remove the brake relay from its socket and aempt to restart the engine. If the engine starts, it is likely that the relay is not correct for this application or the transient protection resistor has failed. Replace the relay with the correct component.
If the engine does not start, the problem may exist with the application reverse mow circuit, the application safeties or with the key switch keeping the ignition shutdown line tied to engine ground.
Remove the engine shutdown (kill) lead from the application wire harness and aempt to start the engine again.
If the engine still does not start, you may have a fuel or ignition problem.
7
Perform other test associated with the charging stator and rectier-regulator to further determine root cause.
7.15
Page 68
Section 7 Electrical System and Components
Electric Starters
These engines use inertia drive starting motors.
Operation
When power is applied to the starter, the armature rotates. As the armature rotates, the drive pinion moves out on the splined drive sha and into mesh with the ywheel ring gear. When the pinion reaches the end of the drive sha, it rotates the ywheel and cranks the engine.
When the engine starts, the ywheel rotates faster than the starter armature and drive pinion. This moves the drive pinion out of mesh with the ring gear and into the retracted position. When power is removed from the starter, the armature stops rotating and the drive pinion is held in the retracted position by the anti-dri spring.
Starting Motor Precautions
NOTE: Do not crank the engine continuously for
more than 10 seconds at a time. If the engine does not start, allow a 60-second cool-down period between starting aempts. Failure to follow these guidelines can burn out the starter motor.
NOTE: If the engine develops sucient speed to
disengage the inertia drive starter but does not keep running (a false start), the engine rotation must be allowed to come to a complete stop before aempting to restart the engine. If the starter is engaged while the
ywheel is rotating, the starter pinion and ywheel ring gear may clash, resulting in
damage to the starter.
NOTE: If the starter does not crank the engine, shut
o the starter immediately. Do not make further aempts to start the engine until the condition is corrected.
NOTE: Do not drop the starter or strike the starter
frame or end cap. Doing so can damage the starter.
Troubleshooting Guide - Starting Difficulties
Problem
Starter
Does Not
Energize
Starter Energizes But Turns
Slowly
Possible Fault Correction
Battery
Wiring
Starter Switch
or Solenoid
Battery
Brushes
Transmission
or
Engine
1. Check the specic gravity of baery. If low, recharge or replace baery as necessary.
1. Clean corroded connections and tighten loose connections.
2. Replace wires in poor condition.
1. Bypass the switch or solenoid with a jumper wire. If starter cranks normally, replace the faulty components.
1. Check the specic gravity of baery. If low, recharge or replace baery as necessary.
2. Baery too small, must be at least 250 cold-cranking amps.
1. Check for excessively dirty or worn brushes and commutator. Clean commutator using a coarse cloth (not emery cloth).
2. Replace brushes if excessively or unevenly worn.
1. Make sure the clutch or transmission is disengaged or placed in neutral. This is especially important on equipment with
hydrostatic drive. The transmission must be exactly in neutral to
prevent resistance which could keep the engine from starting.
2. Check for seized engine components such as the bearings, connecting rod, and piston.
7.16
Page 69
Starter Removal and Installation
Refer to the Disassembly and Reassembly Sections for starter removal and installation procedures.
Starter Drive Service
Every 500 hours of operation, clean and lubricate the splines on the starter drive sha. If the drive pinion is worn, or has chipped or broken teeth, it must be replaced. See Figure 7-14.
It is not necessary to completely disassemble the starter to service the drive components.
Section 7
Electrical System and Components
Figure 7-15. Assembling Inner Half of Tool Around The Armature Shaft and Retaining Ring.
Spring Retainer
Drive Nut (Collar)
Figure 7-14. Drive Components.
1. Disassemble the retaining ring, use tool (See Section 2).
2 Referring to Figure 7-14, grasp the spring retainer
and push it toward the starter, compressing the anti-dri spring and exposing the retaining ring.
3. Holding the spring retainer in the retracted position, assemble the inner halves of the removal tool around the armature sha with the retaining ring in the inner groove (see Figure 7-15). Slide the collar over the inner halves to hold them in position.
Retaining Ring
Anti­Drift Spring
Drive Pinion
4. Thread the center screw into the removal tool until you feel resistance. Use a wrench (1 1/8" or adjustable) to hold the base of the removal tool. Use another wrench or socket (1/2" or 13 mm) to turn the center screw clockwise (see Figure 7-16). The resistance against the center screw will tell you when the retaining ring has popped out of the groove in the armature sha.
7
Figure 7-16. Holding Tool and Turning Center Screw (Clockwise) to Remove Retaining Ring.
5. Remove the drive components, and drive nut (collar) from the armature sha, paying aention to the sequence. If the splines are dirty, clean them with solvent.
6. The splines should have a light lm of lubricant. Relubricate as necessary with Kohler bendix starter lubricant (See Section 2). Reinstall or replace the drive components, assembling them in the same sequence as they were removed.
7.17
Page 70
Section 7 Electrical System and Components
Retaining Ring Installation
1. Position the retaining ring in the groove in one of the inner halves. Assemble the other half over the top and slide on the outer collar.
2. Be certain the drive components are installed in correct sequence onto the armature sha.
3. Slip the tool over the end of the armature sha, so the retaining ring inside is resting on the end of the sha. Hold the tool with one hand, exerting slight pressure toward the starter. Tap the top of the tool with a hammer until you feel the retaining ring snap into the groove. Disassemble and remove the tool.
4. Squeeze the retaining ring with pliers to compress it into the groove.
5. Assemble the inner halves with the larger cavity around the spring retainer (see Figure 7-17). Slide the collar over them and thread the center screw in until resistance is felt.
3. Remove the thru bolts and recessed hex nuts.
4. Remove the commutator end cap and li out the brush carrier assembly with the brushes and springs.
5. Remove the drive end cap, then pull the armature with the thrust washer and wave washer (as equipped) out of the starter frame.
Retaining Ring
Retainer
Anti-Drift Spring
Pinion
Drive Nut (Collar)
Hex Flange Nuts
Drive End Cap
Thrust Washer
Figure 7-17. Assembling Larger Inner Half Around Spring Retainer.
6. Hold the base of the tool with a 1 1/8" wrench and turn the center screw clockwise with a 1/2" or 13 mm wrench to draw the spring retainer up around the retaining ring. Stop turning when the resistance increases. Disassemble and remove the tool.
Starter Disassembly
1. Remove the drive components following the instructions for servicing the drive.
2. Remove the hex ange nut and insulating washer from the positive (+) brush lead stud.
Wave Washer
Armature
Frame Assembly
Brush Carrier Assembly
Commutator End Cap
Insulating Washer
Hex Flange Nut
Thru Bolts
Figure 7-18. Inertia Drive Electric Starter.
7.18
Page 71
Section 7
Electrical System and Components
Brush Replacement
1. Remove the hex ange nut and insulating washer from the positive (+) brush lead stud.
2. Remove the thru bolts and captured hex nuts.
3. Remove the commutator end cap, then pull the brush carrier assembly out of the frame. See
Figure 7-19.
Figure 7-19. Removing Brush Carrier Assembly.
Commutator Service
Clean the commutator with a coarse, lint free cloth. Do not use emery cloth.
If the commutator is badly worn or grooved, turn it down on a lathe or replace the armature.
2. Insert the armature into the starter frame. The magnets will hold it in place. See Figure 7-21.
Figure 7-21. Armature Installed in Starter Frame.
3. Align the holes with the spaces between the magnets and install the drive end cap onto the front of the frame.
4. If the brush assembly is not being replaced, position the springs and brushes within their pockets in the carrier; move them to the retracted position, and install carton staples to retain them. See Figure 7-22. Replacement brushes come pre-assembled in the carrier housing, retained with two carton staples.
7
Starter Reassembly
1. Place the wave washer, followed by the thrust washer onto the drive sha of the armature. See Figure 7-20.
Figure 7-20. Washers Installed on Armature.
Figure 7-22. Brush Carrier Assembly with Staples.
7.19
Page 72
Section 7 Electrical System and Components
5. Hold the brush holder assembly with the positive brush lead stud up. Align the molded sections with the corresponding cutouts in the starter frame and slide the brush carrier assembly into place. The commutator will push the carton staples out as the brush assembly is inserted. See Figure 7-23.
Figure 7-23. Installing Brush Carrier Using Staples.
6. Position the commutator end cap over the brush assembly, aligning the holes for the stud terminal and the thru bolts.
8. Install the insulating washer and hex ange nut onto the positive (+) brush lead stud. Make sure the stud is centered and does not touch the metal end cap. Torque the hex ange nut to 2.2-4.5 N·m (20-40 in. lb.).
NOTE: Aer installation and connection of the
starter lead, torque the outer nut to
1.6-2.8 N·m (12-25 in. lb.), do not over torque.
9. Lubricate the drive sha with Kohler bendix starter drive lubricant (See Section 2). Install the drive components following the instructions for servicing the drive. The completed starter is shown in Figure 7-25.
7. Install the thru bolts and hex nuts. Torque to
3.3-3.9 N·m. (30-35 in. lb.). See Figure 7-24.
Figure 7-24. Torquing Thru Bolts.
Figure 7-25. Assembled Starter.
7.20
Page 73
Disassembly
Section 8
Disassembly
WARNING: Accidental Starts!
Disabling engine. Accidental starting can cause severe injury or death. Before working on the engine or
equipment, disable the engine as follows: 1) Disconnect the spark plug lead. 2) Disconnect negative (-) baery cable from baery.
Section 8
The following sequence is suggested for complete engine disassembly. This procedure can be varied to accommodate options or special equipment.
Clean all parts thoroughly as the 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 the manufacturer’s instructions and safety precautions carefully.
Make sure all traces of the cleaner are removed before the engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil.
Typical Disassembly Sequence
1. Drain oil from the crankcase and remove oil lter.
2. Remove blower housing.
3. Disconnect spark plug lead.
4. Remove muffler.
5. Remove rectifier-regulator.
6. Remove electric starter.
7. Remove air cleaner.
8. Remove external governor components, carburetor and fuel pump.
9. Remove ignition module.
10. Remove grass screen, fan, and ywheel.
11. Remove stator.
12. Remove valve cover and cylinder head.
13. Remove closure plate and wiring harness.
14. Remove cam gears, cam shas, and oil pump.
15. Remove connecting rod and piston.
16. Remove piston from connecting rod.
17. Remove piston rings.
18. Remove cranksha and balance weight assembly.
19. Remove balance weight assembly from
cranksha.
20 Remove governor cross sha.
21. Remove PTO and ywheel side oil seals.
Drain Oil from Crankcase and Remove Oil Filter
1. Remove the oil drain plug and oil ll cap/ dipstick. See Figure 8-1.
2. Allow ample time for the oil to drain from the crankcase.
3. Remove and discard the oil lter.
8
Oil Fill Cap/ Dipstick
Oil Filter
Oil Drain Plug
Figure 8-1. Oil Drain Location, Oil Filter, and Oil Fill Cap/Dipstick.
8.1
Page 74
Section 8 Disassembly
Remove Oil Sentry™ Pressure Switch (On Models So Equipped)
1. Disconnect the lead from the Oil Sentry™ pressure switch.
2. Remove the pressure switch from the center passage or adapter elbow in the closure plate. See
Figure 8-2.
Figure 8-2. Removing Oil Sentry™ Switch.
Remove Muffler
1. Remove the hex ange nuts or 5/16-18 capscrews aaching the muer or exhaust system to the engine. Remove any aached brackets. See Figure 8-4.
2. Remove the muer and gasket from the exhaust
port.
Figure 8-4. Removing Exhaust Flange Nuts (Stud Design).
Remove Blower Housing
1. Remove the four shoulder screws securing the blower housing to the closure plate. See Figure
8-3.
2. Li the blower housing and separate the spark
plug lead from the corresponding slot.
Figure 8-3. Removing Blower Housing Screws.
Disconnect Spark Plug Lead
1. Carefully pull on the boot section and disconnect the spark plug lead.
Remove Rectifier-Regulator
1. Unplug the connector from the rectier-regulator.
2. Remove the two screws securing the rectier­regulator to the crankcase. Remove the rectier­regulator. See Figure 8-5.
Figure 8-5. Removing Rectifier-Regulator.
Remove Electric Starter
1. Disconnect the starter lead from the terminal stud.
2. Remove the two hex ange nuts securing the
starter to the closure plate. Remove the starter.
See Figure 8-6.
8.2
Page 75
Figure 8-6. Removing Electric Starter.
Remove Air Cleaner
1. Loosen the two knobs and remove the air cleaner
cover. See Figure 8-7.
Section 8
Disassembly
3. Remove the two hex ange nuts, or single nut
and long mounting screw securing the air cleaner
base. See Figure 8-9.
Figure 8-9. Removing Air Cleaner Base Fasteners.
4. Disconnect the breather hose from the valve cover and remove the air cleaner base and gasket.
See Figure 8-10.
Figure 8-7. Removing Air Cleaner Cover.
2. Remove the precleaner (if so equipped), and the air cleaner element with the formed rubber seal.
See Figure 8-8.
Figure 8-8. Air Cleaner Components.
8
Figure 8-10. Removing Air Cleaner Base and Breather Hose.
Remove External Governor Components, Carburetor, and Fuel Pump
WARNING: Explosive Fuel!
Gasoline is extremely ammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or ames. Do not ll the fuel tank while the engine is hot or
running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition. Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent.
8.3
Page 76
Section 8 Disassembly
1. Shut off the fuel supply. Disconnect the fuel line from the carburetor inlet ing. See Figure 8-11.
If a fuel pump is used, disconnect the pulse line
from the ing on the closure plate. See Figure 8-12.
Figure 8-11. Disconnecting Fuel Line from Carburetor.
Figure 8-13. Removing Heat Deector Screw and
Ground Lead.
3. If the carburetor uses a fuel solenoid, carefully cut the plastic tie strap and disconnect the fuel solenoid lead from the wiring harness. See Figure
8-14.
Figure 8-12. Disconnecting Pulse Line from Fitting.
2. Remove the heat deector mounting screw and
special washer, which also secures the ground
lead for the fuel shut-o solenoid, if so equipped. See Figure 8-13.
8.4
Figure 8-14. Disconnecting Fuel Solenoid Lead.
4. Slide the carburetor outward and disconnect the
throle and choke linkages. See Figure 8-15.
Figure 8-15. Removing Carburetor.
Page 77
5. Mark the mounted position of the speed control
bracket in the sloed holes and remove the two
screws securing the speed control bracket to the closure plate. Note or mark the governor spring hole for correct installation later. Unhook the governor spring, then remove the control bracket
(with fuel pump aached, if equipped) and linkages from the engine. See Figures 8-16 and 8-17.
Figure 8-16. Removing Speed Control Bracket from Closure Plate.
Section 8
Disassembly
Figure 8-18. Removing Governor Lever.
7. Remove the carburetor gasket, then carefully
remove the heat deector and gasket from the intake stud. The heat deector is made from a plastic that is quite brile. Do not pry on the corners, or you risk cracking/breaking the deflector. If prying is necessary to loosen the deflector, carefully pry near the intake stud only. See Figure 8-19. Remove the mounting stud from
the cylinder only if required.
Figure 8-17. Disconnecting Governor Spring.
6. Loosen the hex ange nut and remove the governor lever* from the governor cross sha. See Figure 8-18.
*NOTE: It is recommended that a new governor lever
be installed whenever removal is performed.
8
Figure 8-19. Removing Heat Deflector.
8.5
Page 78
Section 8 Disassembly
8. Remove the insert from the intake port (some
models), if separate from the heat deector. See Figure 8-20.
Insert
Figure 8-20. Removing Insert (Some Models).
Remove Ignition Module
1. Disconnect the kill lead from the ignition module.
2. Rotate the flywheel magnet away from the
module.
3. Remove the RFI sheathed spark plug lead with from retaining clip, if so equipped. See Figure
8-21.
Figure 8-22. Removing Ignition Module.
Remove Grass Screen, Fan, and Flywheel
1. Unsnap the grass screen from the cooling fan. See
Figure 8-23.
Figure 8-23. Removing Grass Screen.
NOTE: Always use a ywheel strap wrench or
ywheel holding tool (see Section 2) to hold
the flywheel when loosening or tightening the flywheel and fan retaining fasteners. Do
not use any type of bar or wedge between
the fins of the cooling fan, as the fins could
become cracked or damaged.
Figure 8-21. Removing Lead from Clip (RFI Suppression Equipped Units.
4. Remove the two hex ange screws and the ignition module. See Figure 8-22.
8.6
2. Remove the retaining screw, washer and the fan
mounting plate, securing the fan and ywheel to the cranksha. See Figure 8-24.
Page 79
Section 8
Disassembly
Figure 8-24. Removing Fan and Flywheel Mounting Hardware.
3. Carefully li the cooling fan to disengage the two drive pins and remove it from the ywheel.
4. Remove the flywheel from the cranksha using a puller. See Figure 8-25.
NOTE: Always use a puller to remove the
ywheel from the cranksha. Do not strike the cranksha or ywheel, as they
could be cracked or damaged.
Figure 8-26. Removing Stator.
Remove the Valve Cover and Cylinder Head
1. Remove the seven screws securing the valve cover
and any aached brackets. See Figure 8-27.
8
Figure 8-27. Removing Valve Cover Screws.
2. Remove the valve cover and gasket from the
cylinder head. See Figure 8-28.
Figure 8-25. Removing Flywheel Using Puller.
5. Remove the flywheel key from the crank sha.
Remove the Stator
1. Remove the two screws securing the stator to the
closure plate bosses. See Figure 8-26.
NOTE: To disconnect the B+ or stator leads from
the wiring harness connector, insert a
small screwdriver, or similar narrow at
blade, and bend down the locking tang of the terminal(s). Gently pull the lead(s) out of the connector.
Figure 8-28. Valve Cover and Gasket Details.
8.7
Page 80
Section 8 Disassembly
3. Loosen the inner set screws (T15 TORX) and
back o the rocker arm adjusting nuts. Remove
the push rods and mark them, so they can be
reinstalled in the same location. See Figure 8-29.
Figure 8-29. Loosening Adjustment Set Screw and Nut.
Figure 8-31. Removing Cylinder Head and Gasket.
6. Remove the drain back check ball (some models) from the keyhole slot in the crankcase. See Figure
8-32. Models without a check ball have an
internal drain back tube in the crankcase.
4. Remove the six hex ange screws securing the
cylinder head. Note the thick washer used on the screw closest to the exhaust port. See Figure
8-30.
Washer
Figure 8-30. Removing Cylinder Head Bolts and Washer.
5. Remove the cylinder head and head gasket. See
Figure 8-31.
Figure 8-32. Removing Drain Back Check Ball from Crankcase (Some Models).
8.8
Page 81
Disassemble Cylinder Head
NOTE: Before disassembly, mark all valve train
components that will be reused, to assure they are reassembled on the same side.
1. Remove the spark plug. See Figure 8-33.
Section 8
Disassembly
Figure 8-35. Removing Valves with Spring Compressor.
Figure 8-33. Removing Spark Plug.
2. Remove the adjustment nuts, pivots and rocker
arms from the pivot studs.
3. Remove the rocker arm pivot studs and push rod
guide plates. See Figure 8-34.
Figure 8-34. Disassembling Rocker Arm Components.
4. Remove the valves.
a. Compress the valve springs using a valve
spring compressor and remove the keepers.
See Figure 8-35.
Remove Closure Plate
1. Remove the fourteen hex ange screws securing
the closure plate to the crankcase. See Figure
8-36. Note the location and position of any
aached clips or clamps.
8
Figure 8-36. Removing Closure Plate Screws.
2. A gasket is used between the closure plate and crankcase. If necessary, carefully tap on the
bosses for the starter or oil lter with a so-
faced mallet to loosen. Do not pry on the gasket surfaces of the crankcase or oil pan, as this can cause damage resulting in leaks.
b. Remove the compressor; then remove the
valve spring caps, valve springs, and valves.
8.9
Page 82
Section 8 Disassembly
3. Remove the closure plate assembly and gasket.
See Figure 8-37.
4. If the wiring harness needs to be separated from the closure plate, pry open the clamps and pull out through the slot.
Figure 8-37. Closure Plate and Gasket Removed from Crankcase.
Disassemble Closure Plate
1. Remove the governor gear and regulating pin assembly. Gently pry upward using the blades of
two small screwdrivers. See Figure 8-38.
NOTE: The governor gear is held onto the sha by
small molded tabs in the gear. When the gear is removed these tabs are destroyed and the gear must be replaced. Governor gear removal is required for closure plate disassembly and cleaning of the oil passages.
2. Remove the six screws securing the oil passage cover to the closure plate. Remove the cover and
gasket. See Figure 8-39.
Figure 8-39. Removing Oil Passage Cover and Gasket.
Remove Cam Gears, Cam Shafts, and Oil Pump
1. Remove the thrust washer(s) and cam gears from
the cam shas. Later models will have a thrust washer on the exhaust side only. See Figure 8-40.
NOTE: The ACR weight and spring normally
captured by the thrust washer and installation of closure plate, will fall out if the exhaust cam gear is turned upside down.
Thrust Washer (Intake Side) Early Models Only
Figure 8-38. Removing Governor Gear.
8.10
Figure 8-40. Removing Cam Gears.
Page 83
2. Remove the screws securing the cam levers to the
crankcase. See Figure 8-41. Mark the cam levers
for proper reassembly.
NOTE: Cam Gear assemblies may contain either two
or four rivets. The four rivet design is shown
in gures.
Figure 8-41. Removing Cam Levers.
3. Pull the exhaust side cam sha and sloed thrust washer, out of the crankcase. See Figure 8-42.
Section 8
Disassembly
Drain Back Tube
Figure 8-43. Removing Drain Back Tube (Some Models).
NOTE: Engine Serial No. 332740003 and Lower, use
a rubber outlet between the oil pump outlet and lower main bearing area. Some models use an open seal with an internal passage to feed oil to the lower bearing. Some models use a closed or solid seal, and the cranksha
is crossed-drilled to feed oil to the lower bearing. See Figure 8-44.
Engine Serial No. 332740003 and Higher, the
outlet of the oil pump is closed and no rubber
seal is used. See Figure 8-45.
Figure 8-42. Removing Exhaust Side Cam Shaft and Slotted Thrust Washer.
4. If the engine contains an internal drain back tube, unhook it from the oil pump and pull it out of the crankcase passage. Check for cracks,
brileness or damage. Replace if questionable in any way. See Figure 8-43.
Open Seal Closed Seal
Figure 8-44. Outlet Seal Styles (Some Models).
Open Outlet Style (Requires Seal)
Figure 8-45. Pump Outlet Styles.
Closed Outlet Style
8
8.11
Page 84
Section 8 Disassembly
5. Remove the two screws securing the oil pump
and intake side cam sha to the crankcase. If
a drain back tube is used, it may be unhooked and removed separately or together with oil
pump. Carefully pull upward on the cam sha to
remove the assembly from the crankcase cavity. A small rubber oil pump outlet seal on the outlet of the oil pump may become dislodged during removal. Do not lose it. See Figures 8-44 and 8-46.
Outlet Seal (Some Models)
Figure 8-46. Intake Cam Shaft and Oil Pump Assembly.
6. If necessary, the oil pump can be separated from the intake side cam sha. Provide appropriate
support for the sha, and drive out the lower
pin. The oil pump assembly can then be removed from the cam sha. See Figure 8-47.
Remove Connecting Rod and Piston
1. Rotate the cranksha so the rod journal is in the 9 o’clock position.
NOTE: If a carbon ridge is present at the top of the
bore, use a ridge reamer to remove it before
aempting to remove the piston.
2. Remove the two hex ange screws and the connecting rod cap. See Figures 8-48.
Figure 8-48. Removing Connecting Rod Cap.
3. Carefully push the connecting rod and the piston
away from the cranksha and out of the cylinder bore. See Figure 8-49.
Figure 8-47. Separating Oil Pump Assembly from Intake Side Cam Shaft.
8.12
Figure 8-49. Removing Piston and Connecting Rod.
Page 85
Section 8
Disassembly
Remove Piston from Connecting Rod
1. Remove the wrist pin retainer and wrist pin. Separate the piston from the connecting rod. See
Figure 8-50.
Figure 8-50. Separating Piston from Connecting Rod.
Remove Piston Rings
1. Remove the top and center compression rings using a ring expander. See Figure 8-51.
Remove Crankshaft and Balance Weight Assembly
1. Carefully remove the cranksha and balance weight assembly from the crankcase. See Figure
8-52. On engines aer Serial No. 3618005223, carefully li the lower control link (for balance weight), off the boss of crankcase as the cranksha is removed. See Figure 8-53.
Figure 8-52. Removing Crankshaft and Balance Weight Assembly (Before Serial No. 3618005213).
2. Remove the oil control ring rails, then remove the spacer.
Figure 8-51. Removing Piston Rings.
8
Figure 8-53. Removing Crankshaft and Link (After Serial No. 3618005223).
8.13
Page 86
Section 8 Disassembly
Balance Weight Disassembly
If necessary, the balance weight assembly can be
separated from the cranksha. Disassemble only if
required.
1. Remove the crank gear from the cranksha and
carefully remove the key from the keyway. See
Figure 8-54.
Figure 8-55. Removing Balance Weight Screw (Guide Shoe Design Before Serial No. 3618005213).
Figure 8-54. Removing Crank Gear Key.
2. Remove the guide shoe from the guide pin on
the ywheel side of the assembly (Before Serial No. 3618005213). See Figure 8-55. Remove the
link from the guide pin on the PTO side of the assembly (Aer Serial No. 3618005223). See
Figure 8-56.
3. Remove the long hex ange screw securing
the two balance weight halves together on the
cranksha. Note the orientation of all parts. The guide pin is on ywheel side for the balance
weight design with the closure plate side guide shoe. The guide pin is on PTO side for the balance weight design with the lower control link. Hold the guide pin with wrench or torx bit socket as required. Do not hold or damage the outside diameter (O.D.) of the guide pin. See
Figure 8-55 or 8-56.
Figure 8-56. Removing Balance Weight Screw and Guide Pin (Control Link Design After Serial No.
3618005223).
8.14
Page 87
4. Mark the weights for proper reassembly and
carefully slide the balance weights o the cranksha eccentrics. See Figures 8-57 and 8-58.
Figure 8-57. Disassembled Balance Weight (Guide Shoe Design Before Serial No. 3618005213).
Section 8
Disassembly
Figure 8-59. Removing Hitch Pin and Washer.
2. Slide the sha inward and remove it through the
inside of the crankcase. Be careful not to lose the
small washer in the inside portion of the sha. See Figure 8-60.
Figure 8-58. Disassembled Balance Weight (Control Link Design After Serial No. 3618005223).
Remove Governor Cross Shaft
1. Remove the hitch pin and washer located on the
outside of the governor cross sha. See Figure 8-59.
8
Figure 8-60. Removing Governor Cross Shaft.
Remove PTO and Flywheel Side Oil Seals
1. Use a seal puller to remove the PTO and ywheel side oil seals. See Figure 8-61.
Figure 8-61. Removing Seal with a Seal Puller.
8.15
Page 88
Section 8 Disassembly
8.16
Page 89
Section 9
Inspection and Reconditioning
Section 9
Inspection and Reconditioning
This section covers the operation, inspection, and repair/reconditioning of major internal engine components. The following components are not covered in this section. They are covered in sections of their own:
Air Cleaner, Section 4 Carburetor and External Governor, Section 5 Ignition, Charging and Electric Starter, Section 7
Clean all parts thoroughly. 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 the manufacturer’s instructions and safety precautions carefully. Use gasket remover to remove old material from the valve cover, cylinder head, crankcase, and oil pan. Do not scrape the gasket surfaces, as this could cause damage that results in leaks.
Make sure all traces of cleaning solvents are removed before the engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil.
Refer to A Guide to Engine Rebuilding (TP-2150) for additional information. Measurement Guide (TP-2159-A) and Engine Inspection Data Record (TP-2435) are also available; use these to record inspection results.
Automatic Compression Release (ACR)
This engine is equipped with an Automatic Compression Release (ACR) mechanism. The ACR lowers compression at cranking speeds to make starting easier.
Operation
The ACR mechanism consists of an actuating spring
and a pivoting yweight/control pin assembly,
located in the exhaust side cam gear. A thrust washer and mounting of the closure plate hold the ACR in position. See Figure 9-1. At cranking speeds (700 RPM
or lower), the spring holds the yweight in and the
rounded surface of the control pin protrudes above the exhaust cam lobe. This pushes the exhaust valve
o its seat during the rst part of the compression stroke. The compression is reduced to an eective
ratio of about 2:1 during cranking.
When the engine is stopped, the spring returns the
yweight/control pin assembly to the compression
release position, ready for the next start.
Control Pin Lower Section
Cam Lobe
Flyweight
Cam Gear
Spring
9
Aer starting, when engine speed exceeds 700 RPM, centrifugal force overcomes the force of the yweight spring. The yweight moves outward, rotating the control pin to expose the at surface, which is lower
than the cam lobe. The control pin no longer has any
eect on the exhaust valve, and the engine operates at
full power.
Thrust Washer
Figure 9-1. ACR Details.
9.1
Page 90
Section 9 Inspection and Reconditioning
Benefits
Reducing the compression at cranking speeds results
in several important benets.
1. The starter and baery can be smaller, more
practical for the applications in which these engines are used.
2. ACR eliminates kickback during starting, so a spark retard/advance mechanism is no longer required.
3. The choke control seing is less critical with ACR. In the event of ooding, excess fuel is blown out
the opened exhaust valve and does not hamper starting.
4. Engines with ACR start much faster in cold weather.
5. Engines with ACR can be started with spark plugs that are worn or fouled. Engines without ACR would be less likely to start with the same plugs.
Cam Gears
Inspection and Service
Inspect the gear teeth and cam lobes of the intake and exhaust cam gears. If the lobes exhibit excessive wear, or the teeth are worn, chipped or broken, replacement of the cam gear(s) will be necessary.
Crankshaft and Crank Gear
Inspection and Service
Inspect the teeth of the crank gear. If the teeth are badly worn, chipped, or some are missing, replacement of the crank gear will be necessary.
Remove the gear by pulling it o the key and cranksha.
Inspect the cranksha bearing journal surfaces for
wear, scoring, grooving, etc. If they show signs of
damage or are out of running clearance specications, the cranksha must be replaced.
Inspect the cranksha keyways. If worn or chipped, replacement of the cranksha will be necessary.
Inspect the crankpin for wear, score marks or aluminum transfer. Slight score marks can be cleaned with crocus cloth soaked in oil. If wear limits are exceeded (see Section 1), it will be necessary to replace
the cranksha.
Crankcase
Inspection and Service
Check all gasket surfaces to make sure they are free of gasket fragments and deep scratches or nicks.
Check the cylinder wall for scoring. In severe cases, unburned fuel can wash the necessary lubricating
oil o the piston and cylinder wall. The piston rings
make metal to metal contact with the wall, causing
scuffing and scoring. Scoring of the cylinder wall can
also be caused by localized hot spots from blocked
cooling ns or from inadequate or contaminated
lubrication.
If the cylinder bore is scored, worn, tapered, or out­of-round, resizing may be possible. Use an inside micrometer or telescoping gauge to determine the amount of wear (refer to Section 1). If wear exceeds the published limits, a 0.08 mm (0.003 in.) oversize piston is available. If the cylinder will not clean up at 0.08 mm (0.003 in.) oversize, a short block or replacement engine will need to be considered.
Honing
While most commercially available cylinder hones can be used with either portable drills or drill presses, the use of a low speed drill press is preferred as it facilitates more accurate alignment of the bore in
relation to the cranksha counter bore. Honing is best
accomplished at a drill speed of about 250 RPM and 60 strokes per minute. Aer installing coarse stones in
hone, proceed as follows:
1. Lower the hone into the bore and, aer centering,
adjust it so that the stones are in contact with
the cylinder wall. Use of a commercial cuing-
cooling agent is recommended.
2. With the lower edge of each stone positioned even with the lowest edge of the bore, start the drill and honing process. Move the hone up and down while resizing to prevent the formation of
cuing ridges. Check the size frequently. Make
sure the bore is cool when measuring.
9.2
Page 91
Section 9
Inspection and Reconditioning
3. When the bore is within 0.064 mm (0.0025 in.)
of desired size, remove the coarse stones and replace with burnishing stones. Continue with the burnishing stones until within 0.013 mm
(0.0005 in.) of desired size and then use nish
stones (220-280 grit) and polish to nal size. A
crosshatch should be observed if honing is done correctly. The crosshatch should intersect at
approximately 23-33° o the horizontal. Too at
an angle could cause the rings to skip and wear excessively, too steep an angle will result in high oil consumption (refer to Figure 9-2).
Measuring Piston-to-Bore Clearance
Before installing the piston into the cylinder bore, it is necessary that the clearance be accurately checked.
This step is oen overlooked, and if the clearances are not within specications, engine failure will usually
result.
NOTE: Do not use a feeler gauge to measure piston-
to-bore clearance – it will yield inaccurate measurements. Always use a micrometer.
Use the following procedure to accurately measure the piston-to-bore clearance:
1. Use a micrometer and measure the diameter of
the piston perpendicular to the piston pin, up
8 mm (0.314 in.) from the boom of the piston
skirt as indicated in Figure 9-3.
Measure 8 mm (0.314 in.) Above the Bottom of Piston Skirt at Right Angles to Piston Pin.
Figure 9-2. Cylinder Bore Crosshatch after Honing.
4. Aer honing, check the bore for roundness, taper,
and size. Use an inside micrometer, telescoping gauge, or bore gauge to take measurements. The measurements should be taken at three locations in the cylinder – at the top, middle,
and boom. Two measurements should be taken
(perpendicular to each other) at each of the three locations.
Clean Cylinder Bore after Honing
Proper cleaning of the cylinder walls following honing
is critical. Grit le in the cylinder bore can destroy an engine in less than one hour of operation aer a
rebuild.
The final cleaning operation should always be a
thorough scrubbing with a brush and hot, soapy water. Use a strong detergent that is capable of breaking down the machining oil while maintaining a good level of suds. If the suds break down during cleaning, discard the dirty water and start again with more hot water and detergent. Following the scrubbing, rinse the cylinder with very hot, clear water, dry it completely, and apply a light coating of engine oil to prevent rusting.
8 mm (0.314 in.)
Figure 9-3. Measuring Piston Diameter.
2. Use an inside micrometer, telescoping gauge, or bore gauge and measure the cylinder bore. Take the measurement approximately 63.5 mm (2.5 in.) below the top of the bore and perpendicular to the piston pin.
3. Piston-to-bore clearance is the piston diameter subtracted from the bore diameter (step 2 minus step 1).
Balance Weight Assembly
The balance weight assembly counterbalances
the cranksha weights and internal forces during
operation to minimize vibration. Several key areas of the balance weight must be checked before installation and use. Additionally, the mating components
(cranksha eccentrics and closure plate guide channel)
must also be inspected for wear or damage.
Use the following procedure to check the balance weight and matching components.
9
9.3
Page 92
Section 9 Inspection and Reconditioning
Balance Weight-to-Eccentric Clearance
Before the balance weight assembly is reassembled to
the cranksha, the running clearance to the cranksha
eccentrics must be accurately checked. Failure to maintain the required clearances will result in vibration or engine failure.
NOTE: Do not use a feeler gauge to measure balance
weight-to-eccentric clearance.
Measuring Balance Weight to Crankshaft Eccentric Ring(s) Clearance
1. Use an inside micrometer, telescoping gauge, or bore gauge and measure the inside diameter of the balance weight bearing surface. Take two measurements 90° to each other on each weight. See Figure 9-4.
3. The running clearance is the eccentric diameter subtracted from the balance weight bearing diameter (step 1 minus step 2). If the measurements are outside the maximum
wear limits listed in Section 1, the aected
component(s) must be replaced.
Measuring Balance Weight Guide Pin and Guide Shoe-to-Closure Plate Guide Channel Running Clearance
1. Use an outside micrometer and measure the outside width of the balance weight guide shoe. See Figure 9-6.
Figure 9-4. Measuring Balance Weight Bearing Surface.
2. Then use an outside micrometer and measure
across each eccentric on the cranksha. Again
take two measurements 90° to each other. See Figure 9-5.
Figure 9-6. Measuring Balance Weight Guide Shoe.
2. Use an inside micrometer, telescoping gauge or similar tool and measure the width of the guide channel in the closure plate. See Figure 9-7. Record these dimensions.
Figure 9-7. Measuring Guide Channel in Closure Plate.
Figure 9-5. Measuring Crankshaft Eccentric.
9.4
Page 93
Section 9
Inspection and Reconditioning
3. Use an outside micrometer again and measure the O.D. of the balance weight guide pin. See Figure 9-8.
Figure 9-8. Measuring Guide Pin O.D.
4. Use a split ball gauge or dial calipers and measure the I.D. of the corresponding hole in the guide shoe. See Figure 9-9. Record these dimensions.
Flywheel
Inspection
Inspect the ywheel for cracks and check the keyway for wear or damage. Replace the ywheel if cracked. If the flywheel key is sheared or the keyway is damaged, replace the cranksha, ywheel, and key.
Inspect the ring gear for cracks or damage. Ring gears
are not available separately. Replace the ywheel if the
ring gear is damaged.
Figure 9-9. Measuring Guide Shoe Hole I.D.
If any of the measurements taken are outside the
maximum wear limits listed in Section 1, the aected
component(s) must be replaced.
9
9.5
Page 94
Section 9 Inspection and Reconditioning
Cylinder Head and Valves
Inspection and Service
Carefully inspect the valve mechanism parts. Inspect the valve springs and related hardware for excessive wear
or distortion. Check the valves and valve seats for evidence of deep piing, cracks, or distortion. Check the running clearance between the valve stems and guides. See Figure 9-10 for valve details and specications.
Exhaust Valve
F
B
Intake Valve
E
D
G
A
C
A
C
E
D
F
G
B
A B C D E F G
Figure 9-10. Valve Details.
9.6
Seat Angle Guide Depth Guide I.D.
Valve Head Diameter
Valve Face Angle Valve Margin (Min.) Valve Stem Diameter
Dimension
Intake Exhaust
89°
10.20 mm
6.038/6.058 mm
37.625/37.375 mm 45°
1.5 mm
5.982/6.000 mm
89°
6.2 mm
6.038/6.058 mm
32.125/32.375 mm 45°
1.5 mm
5.970/5.988 mm
Page 95
Section 9
Inspection and Reconditioning
Hard starting, or loss of power accompanied by high fuel consumption, may be symptoms of faulty valves. Although these symptoms could also be aributed to worn rings, remove and check the valves rst. Aer
removal, clean the valve heads, faces, and stems with a power wire brush. Then, carefully inspect each valve for defects such as warped head, excessive corrosion, or worn stem end. Replace valves found to be in bad condition. A normal valve and valves in bad condition are shown in the accompanying illustrations.
Normal: Even aer long hours of operation a valve
can be reconditioned and reused if the face and margin are in good shape. If a valve is worn to where the margin is less than 1/32" do not reuse it. The valve shown was in operation for almost 1000 hours under controlled test conditions.
Bad Condition: The valve depicted here should be replaced. Note the warped head; margin damaged
and too narrow. These conditions could be aributed
to excessive hours or a combination of poor operating conditions.
Leakage: A poor grind on a valve face or seat will allow leakage, resulting in a valve burned on one side only.
9
Coking: Coking is normal on intake valves and is not harmful. If the seat is good, the valve could be reused
aer cleaning.
9.7
Page 96
Section 9 Inspection and Reconditioning
Excessive Combustion Temperatures: The white deposits seen here indicate very high combustion temperatures, usually due to a lean fuel mixture.
Stem Corrosion: Moisture in fuel or from condensation are the most common causes of valve stem corrosion. Condensation occurs from improper preservation during storage and when engine is repeatedly stopped before it has a chance to reach normal operating temperatures. Replace corroded valves.
Gum: Gum deposits usually result from using stale
gasoline. This condition is oen noted in applications where fuel is not drained out of tank during the o
season. Gum is a prevalent cause of valve sticking. The cure is to ream the valve guides and clean or replace the valves, depending on their condition.
9.8
Overheating: An exhaust valve subject to overheating will have a dark discoloration in the area above the valve guide. Worn guides and faulty valve springs may cause this condition. Also check for clogged air
intake, and blocked ns when this condition is noted.
Page 97
Valve Guides
If a valve guide is worn beyond specications, it will
not guide the valve in a straight line. This may result in burned valve faces or seats, loss of compression, and excessive oil consumption.
To check valve guide-to-valve stem clearance, thoroughly clean the valve guide and, using a split­ball gauge, measure the inside diameter. Then, using an outside micrometer, measure the diameter of the valve stem at several points on the stem where it moves in the valve guide. Use the largest stem diameter to calculate the clearance. If the intake clearance exceeds 0.038/0.076 mm (0.0015/0.0030 in.) or the exhaust clearance exceeds 0.050/0.088 mm (0.0020/0.0035 in.), determine whether the valve stem or guide is responsible for the excessive clearance.
Maximum (I.D.) wear on the intake valve guide is
6.135 mm (0.2415 in.) while 6.160 mm (0.2425 in.)
is the maximum allowed on the exhaust guide. The guides are not removable. If the guides are within limits but the valve stems are worn beyond limits, replace the valves.
Valve Seat Inserts
Hardened steel alloy intake and exhaust valve seat inserts are press ed into the cylinder head.
The inserts are not replaceable, but they can be
reconditioned if not too badly pied or distorted. If
the seats are cracked or badly warped, the cylinder head should be replaced.
Recondition the valve seat inserts following the
instructions provided with the valve seat cuer being used. A typical cuer is shown in Figure 9-11. The final cut should be made with an 89° cuer as specied for
the valve seat angle in Figure 9-10. With the proper 45° valve face angle, and the valve seat cut properly (44.5° as measured from centerline when cut 89°) this would result in the desired 0.5° (1.0° full cut) interference angle where the maximum pressure occurs on the valve face and seat.
Section 9
Inspection and Reconditioning
Valve Seat Cutter
Pilot
Figure 9-11. Typical Valve Seat Cutter.
Lapping Valves
Reground or new valves must be lapped in, to provide a good seal. Use a hand valve grinder with suction
cup for nal lapping. Lightly coat valve face with ne
grade of grinding compound, then rotate valve on seat with grinder. Continue grinding until 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. Aer drying cylinder
head, apply a light coating of engine oil to prevent rusting.
Pistons and Rings
Inspection
Scuffing and scoring of pistons and cylinder walls
occurs when internal temperatures approach the welding point of the piston. Temperatures high enough to do this are created by friction, which is
usually aributed to improper lubrication, and/or
overheating of the engine.
Normally, very lile wear takes place in the piston
boss-piston pin area. If the original piston and
connecting rod can be reused aer new rings are
installed, the original pin can also be reused, but new piston pin retainers are required. The piston pin is part of the piston assembly; if the pin boss or the pin are worn or damaged, a new piston assembly is required.
9
Ring failure is usually indicated by excessive oil consumption and blue exhaust smoke. When rings fail, oil is allowed to enter the combustion chamber
where it is burned along with the fuel. High oil
consumption can also occur when the piston ring end gap is incorrect because the ring cannot properly conform to the cylinder wall under this condition. Oil control is also lost when ring gaps are not staggered during installation.
9.9
Page 98
Section 9 Inspection and Reconditioning
When cylinder temperatures get too high, lacquer and varnish collect on pistons causing rings to stick which results in rapid wear. A worn ring usually takes on a shiny or bright appearance.
Scratches on rings and pistons are caused by abrasive material such as carbon, dirt, or pieces of hard metal.
Detonation damage occurs when a portion of the fuel charge ignites spontaneously from heat and pressure
shortly aer ignition. This creates two ame fronts
that meet and explode to create extreme hammering
pressures on a specic area of the piston. Detonation
generally occurs from using low octane fuels.
Preignition or ignition of the fuel charge before the timed spark can cause damage similar to detonation.
Preignition damage is oen more severe than
detonation damage. Preignition is caused by a hot spot in the combustion chamber from sources such
as glowing carbon deposits, blocked ns, improperly
seated valve, or wrong spark plug. See Figure 9-12 for some common types of piston and ring damage.
Replacement pistons are available in STD and 0.08 mm (0.003 in.) oversize, which include new rings and piston pins. Service replacement piston ring sets are also available separately. Always use new piston rings when installing pistons. Never reuse old rings.
The cylinder bore must be deglazed before service ring sets are used.
Overheated or Deteriorated Oil
Figure 9-12. Common Types of Piston and Ring Damage.
9.10
Abrasive Scratched RingsStuck, Broken Rings
Scored Piston and Rings
Page 99
Some important points to remember when servicing piston rings:
1. If the cylinder bore is within the wear limits (refer to Section 1) and the old piston is within wear
limits, free of score or scuff marks, the old piston
may be reused.
2. Remove old rings and clean up grooves. Never
reuse old rings.
3. Before installing the rings on the piston, place each of the top two rings in its running area in the cylinder bore and check the end gap (see Figure
9-13). Compare to the listed specications.
Top and Middle Compression Ring End Gap New Bore
Top Ring .....................0.15/0.40 mm (0.006/0.016 in.)
Middle Ring ............... 0.30/0.55 mm (0.012/0.022 in.)
Max. Used Bore .........0.77 mm (0.030 in.)
Section 9
Inspection and Reconditioning
Figure 9-14. Measuring Piston Ring Side Clearance.
Install Piston Rings
To install piston rings, proceed as follows:
NOTE: Rings must be installed correctly. Ring
installation instructions are usually included with new ring sets. Follow instructions carefully. Use a piston ring expander to
install rings. Install the boom (oil control) ring first and the top compression ring last.
Refer to Figure 9-15.
Figure 9-13. Measuring Piston Ring End Gap.
4. Aer installing the new compression (top and
middle) rings on the piston, check piston-to-ring side clearance. The maximum recommended side clearance for each ring is 0.04 mm (0.0016 in.). If
the side clearance is greater than specied, a new
piston must be used. Refer to Figure 9-14.
Top Compression Ring-to-Groove
Side Clearance ................................0.04 mm (0.0016 in.)
Middle Compression Ring-to-Groove
Side Clearance ...............................0.04 mm (0.0016 in.)
Piston Ring
End Gap
Identication
Mark
Piston
Top Compression Ring
Center Compression Ring
Rails
Oil Control Ring (Three Piece)
Figure 9-15. Piston Ring Installation.
Expander
9
9.11
Page 100
Section 9 Inspection and Reconditioning
1. Oil Control Ring (Boom Groove): Install the
expander and then the rails. Make sure the ends of the expander are not overlapped.
2. Compression Ring (Center Groove): Install the center ring using a piston ring installation tool.
Make sure the identication mark is up when the
ring is installed.
3. Compression Ring (Top Groove): Install the top ring using a piston ring installation tool. Make
sure the identication mark is up when the ring
is installed.
Connecting Rods
Inspection and Service
Check the bearing area (big end) for score marks and excessive wear (measure running and side clearances; refer to Section 1. Service replacement connecting rods are available in STD crankpin size.
Oil Pump Assembly and Pressure Relief Valve
Inspection and Service
The closure plate must be removed to inspect and service the oil pump. Refer to the Disassembly and Reassembly Sections (8 and 10) for removal and reinstallation procedures. Check the oil pump and gears for cracks, damage, wear, and smooth rotation. Replace the pump if any binding is noted or reuse is questionable in any way.
A pressure relief valve is built into the oil pump to limit maximum pressure. It is not serviceable. If a problem exists with the pressure relief valve, the oil pump assembly should be replaced.
Oil Passages
Figure 9-16. Oil Passages in Closure Plate.
Oil Passages
Figure 9-17. Oil Passages in Passage Cover.
Use a new passage cover gasket and install the passage cover onto the closure plate. Reinstall the six mounting screws and torque to 4.0 N·m (35 in. lb.), following the sequence in Figure 9-18.
Closure Plate and Passage Cover
Inspection and Service
If disassembly was performed, inspect and ensure the oil passages in the closure plate and the passage cover are completely clean and not obstructed in any way. See Figures 9-16 and 9-17. Check straightness of the
passage cover if required, against a at surface.
9.12
4
1
Figure 9-18. Torque Sequence for Passage Cover.
5
6
2
3
Loading...