Kohler COMMAND CH18-745 Service Manual
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Kohler COMMAND CH18-745 Service Manual

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S
M
ERVICE
ANUAL
COMMAND
CH18-745
H
C
ORIZONTAL
RANKSHAFT

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Summary of Contents for Kohler COMMAND CH18-745

  • Page 1 ERVICE ANUAL COMMAND CH18-745 ORIZONTAL RANKSHAFT...

  • Page 2: Section 1 Safety And General Information

    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.
  • Page 3 Section 1 Safety and General Information WARNING Explosive Fuel can cause fires and severe burns. Stop engine before filling fuel tank. Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or flames.

  • Page 4: Engine Identification Numbers

    Engine Identification Numbers When ordering parts, or in any communication involving an engine, always give the Model, Specification and Serial Numbers, including letter suffixes if there are any. The engine identification numbers appear on a decal, or decals, affixed to the engine shrouding. See Figure 1-1.

  • Page 5: Oil Recommendations

    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 are not approved. 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.

  • Page 6: Periodic Maintenance Instructions

    • Replace fuel filter Perform these maintenance procedures more frequently under extremely dusty, dirty conditions. Have a Kohler Engine Service Dealer perform this service. Cleanout Kits 25 755 20-S (black) or 25 755 21-S (gold) allow cooling areas to be cleaned without removing shrouds.
  • Page 7 Section 1 Safety and General Information Figure 1-4. Typical Engine Dimensions CH Series with Standard Flat Air Cleaner. Dimensions in millimeters. Inch equivalents shown in ().
  • Page 8 Section 1 Safety and General Information Dimensions in millimeters. Inch equivalents shown in (). Figure 1-5. Typical Engine Dimensions CH EFI Series with Heavy-Duty Air Cleaner.
  • Page 9 Section 1 Safety and General Information General Specifications¹ Power (@ 3600 RPM, corrected to SAE J1995) CH18 ... 13.4 kW (18 HP) CH20 ... 14.9 kW (20 HP) CH22/23 ... 16.4 kW (22 HP) CH25, CH730 ... 18.4 kW (25 HP) CH26 ...
  • Page 10 Camshaft End Play (With Shim) ... 0.076/0.127 mm (0.0030/0.0050 in.) Running Clearance ... 0.025/0.063 mm (0.0010/0.0025 in.) Bore I.D. New ... 20.000/20.025 mm (0.7874/0.7884 in.) Max. Wear Limit ... 20.038 mm (0.7889 in.) Camshaft Bearing Surface O.D. New ... 19.962/19.975 mm (0.7859/0.7864 in.) Max.
  • Page 11 Section 1 Safety and General Information Closure Plate Closure Plate Fastener Torque ... 24.4 N·m (216 in. lb.) Crankshaft End Play (Free) ... 0.070/0.590 mm (0.0028/0.0230 in.) End Play (With Thrust Bearing Components) ... 0.070/0.270 mm (0.0028/0.0100 in.) Except CH25 Engines Below Serial No. 2403500008 ... 0.050/0.750 mm (0.0020/0.0295 in.) Crankshaft Bore (In Crankcase) New ...
  • Page 12 Cylinder Head Cylinder Head Fastener Torque Hex. Flange Nut - Torque in Two Stages ... initially to 16.9 N·m (150 in. lb.) Head Bolt - Torque in Two Stages ... initially to 22.6 N·m (200 in. lb.) Max. Out-of-Flatness ... 0.076 mm (0.003 in.) Rocker Arm Screw Torque ...
  • Page 13 Section 1 Safety and General Information Muffler Muffler Retaining Nut Torque ... 24.4 N·m (216 in. lb.) Oil Filter Oil Filter Torque ... 10.4-12.7 N·m (90-110 in. lb.) Oil Cooler Oil Cooler/Adapter Nipple Torque ... 27 N·m (20 ft. lb.) Piston, Piston Rings, and Piston Pin Piston-to-Piston Pin Running Clearance ...
  • Page 14 Piston, Piston Rings, and Piston Pin cont. Piston Thrust Face-to-Cylinder Bore² Running Clearance New - CH18, CH20, CH22 (624 cc) ... 0.014/0.057 mm (0.0005/0.0022 in.) New - CH22/23 (674 cc) ... 0.021/0.062 mm (0.0008/0.0024 in.) New - CH25, CH26, CH730-745 ... 0.001/0.045 mm (0.039/0.0018 in.) Speed Control Bracket Fastener Torque ...

  • Page 15: General Torque Values

    Section 1 Safety and General Information Valves and Valve Lifters cont. Exhaust Valve Guide I.D. New ... 7.038/7.058 mm (0.2771/0.2779 in.) Max. Wear Limit ... 7.159 mm (0.2819 in.) Valve Guide Reamer Size Standard ... 7.048 mm (0.2775 in.) 0.25 mm O.S..7.298 mm (0.2873 in.) Intake Valve Minimum Lift ...

  • Page 16: Torque Conversions

    English Fastener Torque Recommendations for Standard Applications Tightening Torque: N·m (in. lb.) + or - 20% Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 Size 8-32 2.3 (20) 10-24 3.6 (32) 10-32 3.6 (32) 1/4-20 7.9 (70) 1/4-28 9.6 (85)
  • Page 17 Section 1 Safety and General Information 1.16...

  • Page 18: Special Tools

    By using tools designed for the job, you can service engines easier, faster, and safer! In addition, you’ll increase your service capabilities and customer satisfaction by decreasing engine downtime. Kohler special tools are handled by SPX Corp., a division of Owatonna Tool Corp. (OTC). The tools are easy to purchase by contacting SPX/OTC by phone, fax, or mail.
  • Page 19 Obtain a flat washer with the correct I.D. to slip on the capscrew and an O.D. of approximately 1 in. Kohler Part No. 12 468 05-S can be used if you don’t have the right size on hand.

  • Page 20: Dielectric Grease

    Figure 2-5. Loctite ® 5900 Aerosol Dispenser. Camshaft Break-in Lubricant Camshaft lubricant, Kohler Part No. 25 357 14-S (Valspar ZZ613), should be used whenever a new camshaft and lifters are installed for proper break-in upon initial startup. Lubricant is included with each...
  • Page 21 Section 2 Special Tools...

  • Page 22: Section 3 Troubleshooting Ch18

    Troubleshooting Guide When troubles occur, be sure to check the simple causes which, at first, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank. Some general common causes of engine troubles are listed below.
  • Page 23 Section 3 Troubleshooting Engine Will Not Idle 1. Dirt or water in the fuel system. 2. Stale fuel and/or gum in carburetor. 3. Faulty spark plugs. 4. Fuel supply inadequate. 5. Idle speed adjusting screw improperly set. 6. Idle fuel adjusting needle improperly set (some models).

  • Page 24: Cleaning The Engine

    Crankcase vacuum is best measured with either a water manometer (SPX Part No. KO1048, formerly Kohler Part No. 25 761 02-S) or a vacuum gauge (SPX Part No. KO3223, formerly Kohler Part No. 25 761 22-S). Complete instructions are provided in the kits.
  • Page 25 SPX Part No. KO3219 (formerly Kohler Part No. 25 761 05-S) is a relatively simple, inexpensive leakdown tester for small engines. The tester includes a quick disconnect for attaching the adapter hose, and a holding tool.
  • Page 26 Air escaping from crankcase breather ... Defective rings or worn cylinder. 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”...
  • Page 27 Section 3 Troubleshooting...

  • Page 28: Section 4 Air Cleaner And Air Intake System

    Air Cleaner and Air Intake System Air Cleaners General Most engines are equipped with a replaceable, high- density paper air cleaner element, surrounded by an oiled foam precleaner, and housed under a flat outer cover. This is typically referred to as the standard air cleaner assembly.
  • Page 29 4. 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 sealing surfaces are bent or damaged.
  • Page 30 5. Check the seal for any damage or deterioration. Replace as necessary. See Figure 4-7. 6. Reinstall the seal, paper element, precleaner, element cover, and wing nut. Figure 4-8. Exploded View of Standard Air Intake System Components. Air Cleaner and Air Intake System 7.

  • Page 31: Heavy-Duty Air Cleaner

    Section 4 Air Cleaner and Air Intake System Figure 4-9. Bracket Retaining Screw. Figure 4-10. Rear Mounting Screws (Used with Plastic Intake Manifold). Figure 4-11. Breather Tube. Air Cleaner Components Whenever the air cleaner cover is removed, or the paper element or precleaner are serviced, check the following: Air Cleaner Element Cover and Seal - Make sure element cover is not bent or damaged.
  • Page 32 4. Do not wash the paper element and inner element or use compressed air, this will damage the elements. Replace dirty, bent or damaged elements with new genuine Kohler elements as required. Handle the new elements carefully; do not use if the sealing surfaces are bent or damaged.
  • Page 33 Make sure the cooling shrouds are reinstalled. *Cleanout kits, Kohler Part No. 25 755 20-S (black) or 25 755 21-S (gold), are recommended to aid inspection and cleanout of the cooling fins. See Figure 4-15.

  • Page 34: Section 5 Fuel System And Governor

    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 are not approved. Section 5 CH18-745...
  • Page 35 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 Tests When the engine starts hard, or turns over but will not start, it is possible that the problem is in the fuel system. To find out if the fuel system is causing the problem, perform the following tests.

  • Page 36: Fuel Pump - Replacement

    Fuel Pump General These engines are equipped with either a pulse or mechanical fuel pump. See Figures 5-1 and 5-2. The pumping action is created by either the oscillation of positive and negative pressures within the crankcase through a hose, or by direct lever/pump actuation off rocker arm movement.
  • Page 37 Fuel System and Governor Carburetor General These engines are equipped with fixed main jet carburetors manufactured by Keihin to Kohler specifications. Most have automatic chokes and fuel shut-off solenoids. Keihin carburetors with accelerator pump features are standard on many models, and are...
  • Page 38 Troubleshooting Checklist When the engine starts hard, runs roughly or stalls at low idle speed, check the following areas before adjusting or disassembling the carburetor. • Make sure the fuel tank is filled with clean, fresh gasoline. • Make sure the fuel tank cap vent is not blocked and that it is operating properly.

  • Page 39: Carburetor Adjustments

    Section 5 Fuel System and Governor Carburetor Adjustments General In compliance with government emission standards, the carburetor is calibrated to deliver the correct air-to- fuel mixture to the engine under all operating conditions. The high-speed mixture is preset and cannot be adjusted. Pre-compliance carburetors contain a low idle fuel adjusting needle, on “certified”...
  • Page 40 2. Disconnect the fuel line from the carburetor. See Figure 5-6. 3. Clean dirt and debris from exterior of carburetor. 4. Remove the four screws holding the two carburetor halves together. Carefully lift the upper body off the carburetor body and disconnect choke linkage.
  • Page 41 Section 5 Fuel System and Governor 7. In order to clean the ‘‘off-idle’’ vent ports and bowl vent thoroughly, use a good carburetor solvent (like Gumout ™ ). Blow clean compressed air through the idle adjusting needle hole. Be careful to use a suitable shop rag to prevent debris from hitting someone.
  • Page 42 Figure 5-8. Carburetor – Exploded View. Components such as the throttle and choke shaft assemblies, throttle plate, choke plate, low idle fuel needle, and others, are available separately. Always refer to the Parts Manual for the engine being serviced, to ensure the correct repair kits and replacement parts are ordered.
  • Page 43 Section 5 Fuel System and Governor Reassembly Reassemble the carburetor using the following steps. See Figure 5-9. 1. Assemble the fuel inlet needle to the float tab. Install the float, float shaft and inlet needle to the air horn. Tighten the screw. Check float height using the procedure found previously in the ‘‘Adjustments’’...
  • Page 44 General The governed speed setting is determined by the position of the throttle control. It can be variable or constant, depending on the engine application. Initial Adjustment NOTE: EFI engines require a special initial adjustment procedure, which is covered in subsection 5B.

  • Page 45: Electronic Governor

    Section 5 Fuel System and Governor Left Side Pull Choke Control Cable Throttle Control Cable Kill Switch Adjusting Screw Dual Control High Speed Lever Stop Screw "Do Not Remove" Figure 5-11. Governor Control Connections. Electronic Governor General The electronic governor regulates engine speed at varying loads.

  • Page 46: Troubleshooting Procedure

    Governor Control Unit (GCU) senses engine speed by pulse voltage inputs from the ignition modules. The GCU regulates the engine speed by variable input voltage from a customer-supplied potentiometer or a single pole, single throw (SPST) switch. Potentiometer Specifications: Wiper Voltage Engine Speed (RPM) 1860 low speed endpoint variable speed endpoint...
  • Page 47 Section 5 Fuel System and Governor 5.14...
  • Page 48 LPG Fuel Systems WARNING: Explosive Fuel! LPG is extremely flammable, is heavier than air, and tends to settle in low areas where a spark or flame could ignite the gas. Do not start or operate this engine in a poorly ventilated area where leaking gas could accumulate and endanger the safety of persons in the area.

  • Page 49: Operation

    Section 5A LPG Fuel Systems Operation In a liquid withdrawal system, the Liquefied Petroleum Gas (LPG) is released from the bottom of the supply tank under high pressure. Upon opening the shut-off valve on the tank, liquid fuel travels out through the high pressure line to the electric lock-off/filter assembly.
  • Page 50 Engine stalls during operation 1. No fuel. 2. Faulty lock-off or blocked filter. 3. Improper governor setting. 4. Damaged diaphragms within regulator. 5. Vacuum line leaking, loose, or pinched. 6. Restricted fuel line. 7. Loose/leaking fuel enrichment hose (Impco carburetor system). Low power 1.
  • Page 51 Section 5A LPG Fuel Systems High Altitude Operation The standard carburetor calibrations will provide proper operation up to altitudes of 1500 m (5000 ft.). No internal changes are necessary or available for either carburetor. NOTE: Carburetor adjustments should be made only after the engine has warmed up.
  • Page 52 Disconnect the fuel enrichment hose from the carburetor fittings to clean or check condition as required. See Figure 5A-6. Replace with a new Kohler high pressure hose (LP rated) if the condition is questionable in any way. Secure new hose using new clamps.
  • Page 53 Section 5A LPG Fuel Systems LPG Carburetor - Reassembly Impco Carburetor 1. Slide the venturi into the carburetor body, aligning the position mark made prior to removal. Correctly installed, the discharge holes should not be visible from the top. 2. Secure with the venturi retaining screw. Torque the screw to 4.0 N·m (36 in.
  • Page 54 Figure 5A-10. Tightening Idle Speed Clamp Mounting Screw. 4. Reset the idle speed adjustment screw back to the original position. High Speed/Stop Collar Position 1. Make sure the idle speed clamp position has already been checked or properly set. 2. Rotate and hold the throttle shaft so the throttle plate is fully open/perfectly vertical.
  • Page 55 The filter inside the lock-off assembly should be replaced every 500 hours of operation, or if it becomes blocked or restricted. Cleaning of the filter element is not recommended. Order a replacement filter element by the appropriate Kohler part number.

  • Page 56: Lpg Regulator

    Vaporizer Assembly The outer surface of the vaporizer should be kept free of dirt and debris accumulation, which will cause a loss of vaporization efficiency. Visual inspection and necessary cleaning should be performed on a regular basis, more frequently under dusty or dirty conditions. The vaporizer should be disassembled, cleaned, and serviced using a rebuild kit every 1500 hours or if a problem is encountered.
  • Page 57 Section 5A LPG Fuel Systems Impco (Beam) Regulator (See Figure 5A-20) LPG vapor enters at point (A), then passes into primary area (B) at point (28), where pressure is reduced from up to 250 psi at the tank to 4.5 psi in area (B).
  • Page 58 Nikki Regulator Primary Chamber (See Figure 5A-21) The primary chamber reduces the high pressure fuel flow from the tank and vaporizer down to approximately 4 psi. Fuel flowing from the vaporizer enters the inlet of the regulator under approximately 76 kPa (11 psi) of pressure.
  • Page 59 LP personnel only. Impco (Beam) Regulator Service Kohler repair kit 24 757 40-S should be used to service the regulator every 1500 hours, or whenever cleaning and servicing is required.

  • Page 60: Table Of Contents

    Electronic Fuel Injection (EFI) Contents Description Initial Starting/Priming Procedure ... 5B.2 Fuel Recommendations ... 5B.2 EFI Fuel System Components ... 5B.3 Operation ... 5B.3 Important Service Notes ... 5B.4 Electrical Components Electronic Control Unit (ECU) ... 5B.4-5B.5 Engine Speed Sensor ... 5B.5-5B.6 Throttle Position Sensor (TPS) and Initialization Procedure ...

  • Page 61: Description

    87 or higher. In countries using the Research method, it should be 90 octane minimum. Gasoline/Alcohol blends Gasohol (up to 10% ethyl alcohol, 90% unleaded gasoline by volume) is approved as a fuel for Kohler EFI engines. Other gasoline/alcohol blends are not approved. Gasoline/Ether blends...

  • Page 62: Efi Fuel System Components

    EFI Fuel System Components General The Electronic Fuel Injection (EFI) system is a complete engine fuel and ignition management design. The system includes the following principal components: • Fuel Pump • Fuel Filter • Fuel Rail • Fuel Line(s) • Fuel Pressure Regulator •...

  • Page 63: Important Service Notes

    Section 5B EFI Fuel System Important Service Notes! • Cleanliness is essential and must be maintained at all times when servicing or working on the EFI system. Dirt, even in small quantities, can cause significant problems. • Clean any joint or fitting with parts cleaning solvent before opening to prevent dirt from entering the system.

  • Page 64: Engine Speed Sensor

    “blink code” diagnosis flashed out through the MIL. An optional computer software diagnostic program is also available, order Kohler Part No. 25 761 23-S. The ECU requires a minimum of 7.0 volts to operate. The adaptive memory in the ECU is operational the...
  • Page 65 Section 5B EFI Fuel System General The engine speed sensor is essential to engine operation; constantly monitoring the rotational speed (RPM) of the crankshaft. A ferromagnetic 60-tooth ring gear with two consecutive teeth missing is mounted on the flywheel. The inductive speed sensor is mounted 1.5 ±...

  • Page 66: Throttle Position Sensor (Tps)

    Throttle Position Sensor (TPS) 1. Throttle Valve Shaft 2. Resistor Track 3. Wiper Arm w/Wiper 4. Electrical Connection Figure 5B-6. Throttle Position Sensor Details. General The throttle position sensor (TPS) is used to indicate throttle plate angle to the ECU. Since the throttle (by way of the governor) reacts to engine load, the angle of the throttle plate is directly proportional to the load on the engine.
  • Page 67 Section 5B EFI Fuel System 4. Leave the leads connected to the pin terminals as described in step 3. Rotate the throttle shaft slowly counterclockwise to the full throttle position. Monitor the dial during rotation for indication of any momentary short or open circuits.
  • Page 68 #24 (violet wire) to the battery voltage pin (red wire), or use jumper plug (SPX Part No. KO3217-9). If using the PC-based diagnostic tool and software (Kohler Part No. 25 761 23-S), go to “Special Tests” and follow the prompts to complete.

  • Page 69: Engine (Oil) Temperature Sensor

    Section 5B EFI Fuel System 5. Remove the jumper wire or plug from the service connector plug in wiring harness. 6. Run the engine at full throttle (above 3000 RPM), to warm up the engine and initiate O function in “closed-loop” operation. 7.

  • Page 70: Oxygen Sensor

    “24 Pin” (MSE 1.0) Plastic-Cased ECU: Check between the #6 and #4 pin terminals. “32 Pin” (MSE 1.1) Plastic-Cased ECU: Check between the #6 and #4 pin terminals. 5. Unplug the sensor connector and check sensor resistance separately. Resistance value should again be 2375-2625 Ω...
  • Page 71 Section 5B EFI Fuel System 1. Oxygen sensor must be hot (minimum of 400°C, 725°F). Run engine for about 5 minutes. With the engine running, disconnect the oxygen sensor lead from the wiring harness. Set VOA meter for DC volts and connect the red lead to the disconnected sensor lead, and the black lead to the sensor shell.

  • Page 72: Electrical Relay

    a. If there is no continuity displayed in either of the tests, check the harness circuit for breaks or damage, and the connections for poor contact, moisture, or corrosion. If no continuity was found in the first test, also check for a poor/broken ground path back through the exhaust system, engine, and mounting (sensor is grounded through its shell).

  • Page 73: Fuel Injectors

    Section 5B EFI Fuel System Terminal #85 - Ignition Switch Voltage Terminal #87A - Not used Terminal #30 - Permanent Battery Voltage Figure 5B-14. Relay Connector. a. Clean the connection and check wiring if circuit was not completed. 3. Set meter for DC voltage. Touch red tester lead to the #30 terminal in relay connector.
  • Page 74 When the key switch is on and the relay is closed, the fuel rail is pressurized, and voltage is present at the injector. At the proper instant, the ECU completes the ground circuit, energizing the injector. The valve needle in the injector is opened electromagnetically, and the pressure in the fuel rail forces fuel down through the inside.
  • Page 75 Section 5B EFI Fuel System Figure 5B-20. Volt Test Light. 2. Make sure all safety switch requirements are met. Crank the engine and check for flashing of test light. Repeat test at other connector. a. If flashing occurs, use an ohmmeter (Rx1 scale) and check the resistance of each injector across the two terminals.

  • Page 76: Ignition System

    8. Thoroughly clean the area around and including the throttle body/manifold and the injectors. 9. Disconnect the throttle linkage and damper spring from the throttle lever. Disconnect the TPS lead from the harness. 10. Remove the manifold mounting bolts and separate the throttle body/manifold from the engine leaving the TPS, fuel rail, air baffle, injectors and line connections intact.

  • Page 77: Spark Plug

    Spark Plugs EFI engines are equipped with Champion (Kohler Part No. 12 132 02-S) resistor style spark plugs. Equivalent alternate brand plugs can also be used, but must be a resistor style plug or permanent damage to the ECU will occur in addition to affecting operation.

  • Page 78: Battery Charging System

    Figure 5B-24. “24 Pin” (MSE 1.0) Plastic-Cased ECU Connector. Figure 5B-25. “32 Pin” (MSE 1.1) Plastic-Cased ECU Connector. The condition of the wiring, connectors, and terminal connections is essential to system function and performance. Corrosion, moisture, and poor connections are more likely the cause of operating problems and system errors than an actual component.

  • Page 79: Fuel Pressure Regulator

    Section 5B EFI Fuel System 1. Connect the black hose of Kohler pressure tester (SPX Part No. KO3217-4), to the test valve in the fuel rail. Route the clear hose into a portable gasoline container or the equipment fuel tank.
  • Page 80 Pressure Regulating Spring Valve Inlet Port Return Port (to tank) Figure 5B-29. Fuel Pressure Regulator Details. Service Depending on the application, the regulator may be located in the fuel tank along with the fuel pump, or outside the tank just down line from the pump. The regulator is a sealed, non-serviceable assembly.

  • Page 81: Fuel Filter

    Fuel Line Service Kit, Part No. 24 353 42-S (containing 5 ft. of high-pressure hose and 10 Oetiker clamps), or use only the type specified. Special Oetiker clamps (Kohler Part No. 24 237 05-S) are used on all fuel line connections to Fuel...

  • Page 82: Throttle Body/Intake Manifold Assembly

    CAUTION: Standard fuel line is not compatible and must not be used! Use only Oetiker clamps (Kohler Part No. 24 237 05-S) on fuel line connections. Throttle Body/Intake Manifold Assembly Low Idle Speed Adjusting Screw Throttle Body Intake Manifold Fuel Rail Figure 5B-35.

  • Page 83: Initial Governor Adjustment

    Section 5B EFI Fuel System The idle speed adjustment procedure remains the same for engines with or without a dampening spring. Typically, no periodic servicing is necessary in this area. If however, removal/replacement of the dampening spring is required, reinstall it as follows: 1.
  • Page 84 Feeler Gauge Figure 5B-39. Inserting Feeler Gauge (Engines Without Stop Screw). b. On engines with a stop screw, pivot the throttle shaft and plate into the “Full Throttle” position, so the tang of the throttle shaft plate is against the end of the high-speed stop screw. See Figure 5B-38.

  • Page 85: Troubleshooting

    Section 5B EFI Fuel System 4. Verify that the governor has been set correctly. With the linkage still retained in the “Full Throttle” position (Step 2), unsnap the bushing clip, separate the linkage from the bushing, and remove the bushing from the lever. Follow Steps 3 and 4 in ‘‘Checking the Initial Adjustment’’.

  • Page 86: Electrical System

    Electrical System The EFI system is a 12 VDC negative ground system, designed to operate down to a minimum of 7.0 volts. If system voltage drops below this level, the operation of voltage sensitive components such as the ECU, fuel pump, and injectors will be intermittent or disrupted, causing erratic operation or hard starting.
  • Page 87 Section 5B EFI Fuel System “35 Pin” (MA 1.7) Metal-Cased ECU Systems Pin # Ignition Coil #1 Engine Speed Sensor ECU Production Test Terminal TPS Initialization Terminal Engine Ground Throttle Position Sensor Oil Temperature Sensor ECU Permanent Battery Voltage ECU Switched Battery Voltage Engine Ground Ignition Coil #2 Vehicle Ground...
  • Page 90 “24 Pin” (MSE 1.0) Plastic-Cased ECU Systems Pin # Permanent Battery Voltage Switched Ignition Voltage Safety Switch Throttle Position Sensor (TPS) and Temperature Sensor Ground Not Used Oil Temperature Sensor Input Not Used Throttle Position Sensor (TPS) Input Speed Sensor Input Speed Sensor Ground Oxygen Sensor Input Not Used (Oxygen Sensor Ground if needed)
  • Page 91 Section 5B EFI Fuel System “32 Pin” (MSE 1.1) Plastic-Cased ECU Systems Pin # Permanent Battery Voltage Switched Battery Voltage TPS Set; “Auto-Learn” Initialization Terminal Throttle Position Sensor (TPS) and Temperature Sensor Ground Not Used Oil Temperature Sensor Input Not Used Throttle Position Sensor (TPS) Input Speed Sensor Input (+) Speed Sensor Ground (-)

  • Page 93: Fuel System

    Section 5B EFI Fuel System Fuel System WARNING: Fuel System Under Pressure! The fuel system operates under high pressure. System pressure must be relieved through the test valve in the fuel rail prior to servicing or removing any fuel system components.
  • Page 94 Example of Diagnostic Display 1. Diagnostic display initiated through ignition key sequencing. Long Pause Figure 5B-43. After the problem has been corrected, the fault codes may be cleared as follows. 1. Disconnect the negative (-) battery cable from battery terminal, or remove the main fuse for the ECU for approximately 1 minute.
  • Page 95 Section 5B EFI Fuel System c i l 3 " " n i n i u l i i n i u l i c i t c i t c i t Note: 1. Idle Switch not used. 2. Diagnostic of "TPS - Signal Implausible" is disabled in code. 3.
  • Page 96 Code: Source: Engine Speed Sensor Explanation: ECU receiving inconsistent tooth count signals from speed sensor. Expected Engine Response: Possible misfire as ECU attempts to resynchronize, during which time fuel and spark calculations are not made. Possible Causes: 1. Engine Speed Sensor Related a.
  • Page 97 Section 5B EFI Fuel System 3. Engine Wiring Harness Related “32 Pin” (MSE 1.1) Plastic-Cased ECU: a. Pin circuits 4, 8, and/or 18 damaged (wiring, connectors). b. Pin circuits 4, 8, and/or 18 routed near noisy electrical signal (coils, alternator). c.
  • Page 98 Code: Source: Oxygen Sensor Explanation: No change in the sensor output signal. Expected Engine Response: “Open loop” operation only, may cause a drop in system performance and fuel efficiency. Possible Causes: 1. Engine Wiring Harness Related a. Pin circuit wiring or connectors. Pin 10 for “35 Pin”...
  • Page 99 Section 5B EFI Fuel System 3. Engine Wiring Harness Related a. Difference in voltage between sensed voltage (pin circuit 17 for metal-cased ECU, pin circuit 2 for plastic-cased ECU) and actual injector voltage (circuit 45/45A). b. Problem in wiring harness. c.
  • Page 100 Code: "32 Pin" (MSE 1.1) Plastic- Cased ECU only. Source: Injector #1 circuit open, shorted to ground, or shorted to battery. Explanation: Injector #1 is not functioning because the circuit is open, shorted to ground, or shorted to battery. Expected Engine Response: Engine will run very poorly with only one cylinder functioning.

  • Page 101: Troubleshooting Flow Chart

    Section 5B EFI Fuel System Code: "32 Pin" (MSE 1.1) Plastic- Cased ECU only. Source: Fuel pump relay circuit open, shorted to ground, or shorted to battery Explanation: Fuel pump, ignition coils, and fuel injectors will not function because the fuel pump relay circuit is either open, shorted to ground, or may be “on”...
  • Page 102 Section 5B EFI Fuel System *Operate for an appropriate period of time based upon original fault codes. Figure 5B-44. 5B.43...

  • Page 103: Flow Chart Diagnostic Aids

    Section 5B EFI Fuel System Flow Chart Diagnostic Aids Diagnostic Aid #1 "SYSTEM POWER" (MIL does not illuminate when key is turned “on”) Possible causes: 1. Battery 2. Main system fuse 3. MIL light bulb burned out 4. MIL electrical circuit problem “35 Pin”...
  • Page 104 Diagnostic Aid #4 “SPEED SENSOR” (MIL does not turn off during cranking). Indicates the ECU is not receiving a signal from the speed sensor. Possible causes: 1. Speed sensor 2. Speed sensor circuit problem “35 Pin” (MA 1.7) Metal-Cased ECU: Pin circuits 3 and 21 “24 Pin”...
  • Page 105 Section 5B EFI Fuel System 5B.46...

  • Page 106: Section 6 Lubrication System

    Lubrication System General This engine uses a full pressure lubrication system. This system delivers oil under pressure to the crankshaft, camshaft and connecting rod bearing surfaces. In addition to lubricating the bearing surfaces, the lubrication system supplies oil to the hydraulic valve lifters.

  • Page 107: Checking Oil Level

    Section 6 Lubrication System Checking 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: 1. Make sure the engine is stopped, level and is cool so the oil has had time to drain into the sump.
  • Page 108 5. Reinstall the oil fill cap. Changing Oil Filter Replace the oil filter at least every other oil change (every 200 hours of operation). Always use a genuine Kohler oil filter. Change the filter as follows. See Figure 6-6. Oil Filter Oil Drain Plug Figure 6-6.
  • Page 109 Section 6 Lubrication System Service Oil Cooler Some engines are equipped with an oil cooler. One style of oil cooler mounts on the engine crankcase and has the oil filter on it. The other style of oil cooler is mounted on the blower housing, separate from the oil filter.
  • Page 110 To install the switch, follow these steps: 1. Apply pipe sealant with Teflon 59241 or equivalent) to the threads of the switch. 2. Install the switch into the tapped hole in the breather cover. See Figure 6-8. 3. Torque the switch to 4.5 N·m (40 in. lb.). Testing Compressed air, a pressure regulator, pressure gauge and a continuity tester are required to test the switch.
  • Page 111 Section 6 Lubrication System...

  • Page 112: Section 7 Retractable Starter

    Retractable Starter WARNING: Spring Under Tension! Retractable starters contain a powerful, recoil spring that is under tension. Always wear safety goggles when servicing retractable starters and carefully follow instructions in this section for relieving spring tension. To Remove Starter 1. Remove the five hex. flange screws securing the starter to the blower housing.
  • Page 113 Section 7 Retractable Starter Slipknot Rope Retainer Figure 7-2. Removing Starter Handle. 3. Remove the rope retainer from inside the starter handle. Untie the single knot and remove the rope retainer and handle. 4. Hold the pulley firmly and untie the slipknot. Allow the pulley to rotate slowly as the spring tension is released.
  • Page 114 Disassembly WARNING: Spring Under Tension! Do not remove the center screw from the starter until the spring tension is released. Removing the center screw before releasing spring tension, or improper starter disassembly, can cause the sudden and potentially dangerous release of the spring. Follow these instructions carefully to ensure personal safety and proper starter disassembly.

  • Page 115: Inspection And Service

    2. Replace all worn or damaged components. Use only genuine Kohler replacement parts as specified in the Parts Manual. All components shown in Figure 7-1 are available as service parts. Do not use nonstandard parts.
  • Page 116 4. Place the brake washer in the recess in starter pulley; over the center shaft. 5. Lubricate the brake spring sparingly with grease. Place the spring on the plain washer. Make sure the threads in the center shaft remain clean, dry, and free of grease and oil.
  • Page 117 Section 7 Retractable Starter...

  • Page 118: Section 8 Electrical System And Components

    Type: The standard spark plug is a Champion RC12YC (Kohler Part No. 12 132 02-S). A high-performance spark plug, Champion Platinum 3071 (used on Pro Series engines, Kohler Part No. 25 132 12-S) is also available. Equivalent alternate brand plugs can also be used. Gap: 0.76 mm (0.030 in.)
  • Page 119 Section 8 Electrical System and Components 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 set to the proper gap and reused.
  • Page 120 Battery General A 12-volt battery with 400 cold cranking amps is generally recommended for starting in all conditions. A smaller capacity battery is often sufficient if an application is started only in warmer temperatures. Refer to the following table for minimum capacities (cca) based on anticipated ambient temperatures.
  • Page 121 Section 8 Electrical System and Components Electronic CD Ignition Systems Starter and Ignition Carburetor Module Solenoid Input Input B+ and Carburetor Solenoid Input Violet Figure 8-3. Electronic CD Ignition System (For Customer Connected Tractor Applications). The SMART-SPARK ignition system used on some ™...
  • Page 122 Kill Switch or ‘‘Off’’ Position of Key Switch Figure 8-4. Capacitive Discharge (Fixed Timing) Ignition System. The timing of the spark is controlled by the location of the flywheel magnet group as referenced to engine top dead center. Figure 8-5. Capacitive Discharge Ignition Module Schematic. Operation: As the flywheel rotates, the magnet grouping passes the input coil (L1).
  • Page 123 Section 8 Electrical System and Components Key Switch or ‘‘Off’’ Position of Key Switch White Spark Plug 0.28/0.33 mm (0.011/0.013 in.) Air Gap Figure 8-6. Capacitive Discharge Ignition System with Spark Advance. The timing of the spark is controlled by the location of the flywheel magnet group as referenced to the engine top dead center and the delay created by the spark advance module.
  • Page 124 Because you have interrupted the kill circuit, it may not stop using the switch. 2. Test for spark on both cylinders with Kohler ignition tester, SPX Part No. KO1046 (formerly Kohler Part No. 24 455 02-S). Disconnect one spark plug lead and connect it to the post terminal of the tester.
  • Page 125 (0.011-0.013 in.), 0.30 mm (0.012 in.) nominal *NOTE: Ignition tester (SPX Part No. KO1046 formerly Kohler Part No. 24 455 02-S) must be used to test ignition on these engines. Use of any other tester can result in inaccurate findings.
  • Page 126 24 584 11 or 24 584 15-S. For small modules with vendor numbers MA-2C or MA-2D (Kohler Part No. 24 584 11), or the larger style modules (24 584 15-S and 24 584 36-S), use a digital ohmmeter to check the resistance values and compare them to the table following.
  • Page 127 Section 8 Electrical System and Components Ignition Module Resistance Table 24 584 03 or 24 584 11 (1 11/16 in. H) Check and/or adjust the ignition module air gap(s). An air gap of 0.28/0.33 mm (0.011/0.013 in.) must be maintained under all three legs of the ignition module(s).
  • Page 128 Seal the base of the ignition module connections with GE/Novaguard G661 (Kohler Part No. 25 357 11-S) or Fel-Pro Lubri-Sel dielectric compound. The beads should overlap between the two connections †...
  • Page 129 Section 8 Electrical System and Components Figure 8-12. 2. Check the SAM part number, stamped on the side of the housing, and determine if you have an analog SAM (ASAM) or a digital SAM (DSAM). Follow sub-step a for an ASAM, and sub-step b for a DSAM.
  • Page 130 Battery Charging System General Most engines are equipped with a 15 or 20 amp regulated charging system. Some have a 25 amp regulated charging system. See Figure 8-14 for the 15/20/25 amp charging system diagram. Some engines utilize a 3 amp unregulated system with optional 70 watt lighting circuit.
  • Page 131 Section 8 Electrical System and Components 15/20/25 amp Regulated Charging System Figure 8-14. Wiring Diagram - 15/20/25 amp Regulated Battery Charging System. Figure 8-15. 15 amp Stator and Rectifier-Regulator. Figure 8-16. 20 amp Stator and Rectifier-Regulator. 8.14...
  • Page 132 1st Style 2nd Style Figure 8-17. 25 amp Stator and Rectifier-Regulators. 3 amp Unregulated Charging System Ground-To-Kill Lead (White) Light Switch Optional Oil Sentry Switch (Indicator Light) Optional Oil Sentry Switch (Shutdown) 12 V. Battery Figure 8-18. Wiring Diagram - 3 amp Unregulated Battery Charging System/70 Watt Lighting. Electrical System and Components (Blue) (Red)
  • Page 133 Ground Strap (or lead) Figure 8-20. Rectifier-Regulator. Testing of the rectifier-regulator may be performed as follows, using the Rectifier-Regulator Tester (SPX Part No. KO3221, formerly Kohler Part No. 25 761 20-S). 8.16 Lighting Stator To Test – NOTE: Disconnect all electrical connections attached to the rectifier-regulator.
  • Page 134 3. Plug the tester into a 110 volt AC outlet supply and turn on the power switch. See Figure 8-22. The ‘‘POWER’’ light should be illuminated and one of the four status lights may be on as well. This does not represent the condition of the part. Figure 8-22.
  • Page 135 Section 8 Electrical System and Components 6. Press the ‘‘TEST’’ button until a ‘‘click’’ is heard and then release. See Figure 8-23. Momentarily one of the four lights will illuminate indicating the partial condition of the part. a. If the ‘‘OK’’ (green) light comes on, disconnect the tester black lead attached to one AC terminal and reconnect it to the other AC terminal.
  • Page 136 Figure 8-28. 3. Plug the tester into a 110 volt AC outlet and turn on the power switch. The ‘‘POWER’’ light should be illuminated and one of the four status lights may be on as well. See Figure 8-22. This does not represent the condition of the part.

  • Page 137: Troubleshooting Guide

    Section 8 Electrical System and Components Troubleshooting Guide 15/20/25 amp Battery Charging Systems When problems occur in keeping the battery charged or the battery charges at too high a rate, the problem can usually be found somewhere in the charging system or with the battery. NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings.
  • Page 138 Troubleshooting Guide 3 amp Battery Charging System with 70 Watt Lighting Stator NOTE: Zero ohmmeters on each scale to ensure accurate readings. Voltage tests should be made with engine running at 3000 RPM - no load. Battery must be good and fully charged. Problem 1.
  • Page 139 Section 8 Electrical System and Components Electric Starting Motors Some engines in this series use inertia drive starting motors while most use solenoid shift starters. The inertia drive types are covered first and the solenoid shift types following. Starting Motor Precautions NOTE: Do not crank the engine continuously for more than 10 seconds at a time.
  • Page 140 4. Clean the splines on drive shaft thoroughly with solvent. Dry the splines thoroughly. 5. Apply a small amount of Kohler electric starter drive lubricant, Part No. 52 357 01-S, to the splines. The use of other lubricants may cause the drive pinion to stick or bind.
  • Page 141 Figure 8-31. Drive Components, ‘‘Bonded’’ Inertia Drive Starter. 2. Disassemble the snap ring removal tool, SPX Part No. KO1049 (formerly Kohler Part No. 25 761 18-S). 3. Again referring to Figure 8-31, grasp the spring retainer and push it toward the starter, compressing the anti-drift spring and exposing the retaining ring.
  • Page 142 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 shaft. 3.
  • Page 143 Section 8 Electrical System and Components NOTE: Use a brush holder tool to keep the brushes in the pockets. A brush holder tool can easily be made from thin sheet metal. See Figure 8-36. Self- Brush Springs Tapping Screw Negative (-) Brush Stud Terminal with Positive (+) Brushes...
  • Page 144 Figure 8-38. Style ‘‘B’’ Commutator End Cap with Brushes. 6. Install the thru bolts and tighten securely. 7. Lubricate the drive shaft with Kohler bendix starter drive lubricant (Part No. 52 357 01-S). Install the drive components following the instructions for servicing the starter drive.
  • Page 145 Brush Replacement The brushes in the starter are part of the starter frame. Brush kit, Kohler Part No. 52 221 01-S, contains four replacement brushes and springs. If replacement is necessary, all four brushes should be replaced.
  • Page 146 Phillips Head Screws Torx Head Screws Figure 8-41. Removing Solenoid Screws. 3. If the solenoid was mounted with Phillips head screws, separate the solenoid and plunger spring from the drive end cap. If the solenoid was mounted with external Torx head screws, the plunger is part of the solenoid, unhook the plunger pin from the drive lever.
  • Page 147 Section 8 Electrical System and Components Figure 8-44. Removing Thru Bolts. 5. Remove the commutator end plate assembly, containing the brush holder, brushes, springs, and locking caps. Remove the thrust washer from inside the commutator end. See Figure 8-45. Figure 8-45. Removing Commutator End Plate Assembly.
  • Page 148 Figure 8-49. Retaining Ring Detail. 11. Remove the retainer from the armature shaft. Save the stop collar. NOTE: Do not reuse the old retainer. Collar Ring Stop Drive Armature Washer Tube Figure 8-51. Delco-Remy Starter. Electrical System and Components Figure 8-50. Removing Retaining Ring. 12.

  • Page 149: Shift Fork

    Section 8 Electrical System and Components Inspection Drive Pinion Check and inspect the following areas: a. The pinion teeth for abnormal wear or damage. b. The surface between the pinion and the clutch mechanism for nicks, or irregularities which could cause seal damage.

  • Page 150: Brush Replacement

    Electrical System and Components Starter Service Clean the drive lever and armature shaft. Apply Kohler electric starter drive lubricant Part No. 52 357 02-S (Versilube G322L or Mobil Temp SHC 32) to the lever and shaft. Clean and check the other starter parts for wear or damage as required.
  • Page 151 5. Lubricate the fork end and center pivot of the drive lever with drive lubricant (Kohler Part No. 52 357 02-S). Position the fork end into the space between the captured washer and the rear of the pinion.
  • Page 152 Figure 8-62. Installing Thrust Washer. 10. Starter reassembly when replacing the Brushes/ Brush Holder Assembly: a. Hold the starter assembly vertically on the end housing, and carefully position the assembled brush holder assembly, with the supplied protective tube, against the end of the commutator/armature.
  • Page 153 Section 8 Electrical System and Components Figure 8-66. Installing Brush Holder Assembly using Tool with Extension. 11. Install the end cap onto the armature and frame, aligning the thin raised rib in the end cap with the corresponding slot in the grommet of the positive (+) brush lead.

  • Page 154: Section 9 Disassembly Ch18

    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(s). 2) Disconnect negative (-) battery cable from battery. General Clean all parts thoroughly as the engine is disassembled.
  • Page 155 Section 9 Disassembly 3. Remove and discard the oil filter. See Figure 9-5. Figure 9-2. Removing Dipstick from Tube. Figure 9-5. Removing Oil Filter. Figure 9-3. Removing Oil Fill Cap from Cover. Figure 9-4. Removing Oil Drain Plug. Figure 9-6. Removing Oil Filter Adapter Nipple. 2.

  • Page 156: Remove Muffler

    Figure 9-7. Removing Oil Cooler. 4. An oil cooler is standard equipment on some models and an option on others. It may be a cast aluminum housing, part of the oil filter adapter, or attached to the blower housing, separated from the oil filter adapter.
  • Page 157 Section 9 Disassembly Figure 9-11. Removing Tube from Breather Cover. 6. Remove the rubber breather tube from the breather cover. See Figure 9-11. Remove Fuel Pump WARNING: Explosive Fuel! Gasoline is extremely flammable and its vapors can explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, away from sparks or flames.
  • Page 158 Figure 9-15. Removing Screws Holding Fuel Pump (Metal Bodied Pump Shown). 4. Note or mark the orientation of the fuel pump, then remove the fuel pump with lines attached as shown in Figure 9-16. Figure 9-16. Remove Fuel Pump and Lines. Mechanical Fuel Pump The mechanical style fuel pump is part of the valve cover assembly.

  • Page 159: Remove External Governor Controls

    Section 9 Disassembly Figure 9-19. Rear Air Cleaner Bracket (Some Models). 2. Mark the spring hole locations and disconnect the spring from the governor lever. See Figure 9-20. Figure 9-20. Disconnecting Spring from Bracket. 3. Remove the choke linkage from the choke actuator lever and carburetor.
  • Page 160 3. Remove the carburetor, throttle linkage and governor lever as an assembly. See Figure 9-24. Figure 9-24. Removing Carburetor Assembly with Governor Lever Attached. 4. Remove the carburetor gasket. 5. If necessary, the carburetor, throttle linkage and governor lever can be separated. Reattach the bushings to the linkage following separation to avoid losing them.
  • Page 161 Section 9 Disassembly Figure 9-28. Remove B+ Lead from Terminal Plug. 3. The rectifier-regulator does not have to be detached from the blower housing. If the engine is equipped with SMART-SPARK should be removed from the cylinder baffle or blower housing. See Figure 9-29. The module willing hang loose as part of the wiring harness.
  • Page 162 Figure 9-32. Removing Metal Grass Screen. 7. Remove the lower blower housing screw and washer securing the rectifier-regulator ground lead or grounding strap. 8. Remove the remaining hex. flange screws and detach the blower housing. See Figure 9-33. 9. Disconnect the plug from the key switch in the blower housing if engine is so equipped.

  • Page 163: Remove Valve Covers

    Section 9 Disassembly Figure 9-36. Breaking Breather Cover Seal. 5. Remove the breather cover and gasket (if used). See Figure 9-37. Figure 9-37. Removing Breather Cover. 6. Remove the breather filter from chamber. See Figure 9-38. Figure 9-38. Removing Breather Filter. 9.10 7.

  • Page 164: Remove Ignition Modules

    Remove Ignition Modules 1. Disconnect the lead(s)* from each ignition module. See Figure 9-41. *Modules for non- SMART-SPARK ignition systems have only one ™ kill lead. Figure 9-41. Disconnecting Leads from Ignition Modules. 2. Rotate the flywheel so the magnet is away from the modules.

  • Page 165: Remove Spark Plugs

    Section 9 Disassembly Remove Spark Plugs 1. Remove the spark plug from each cylinder head. Figure 9-45. Removing Spark Plugs. Remove Cylinder Heads and Hydraulic Lifters NOTE: Cylinder heads are retained using either hex. flange screws or hex. flange nuts and washers on studs.
  • Page 166 Figure 9-47. Removing Cylinder Head Assembly. 4. Remove the lifters from the lifter bores. Use Hydraulic Lifter Tool (SPX Part No. KO1044) Do not use a magnet to remove lifters. Mark the lifters by location, as either intake or exhaust and cylinder 1 or 2.
  • Page 167 Section 9 Disassembly Disassemble Cylinder Heads 1. Remove the two hex. flange screws, rocker arm pivots and rocker arms from the cylinder head. See Figure 9-51. Figure 9-51. Removing Rocker Arms. 2. Compress the valve springs using a valve spring compressor.

  • Page 168: Remove Flywheel

    Figure 9-55. Removing Plastic Type Grass Screen. 2. Remove the four hex. flange screws and fan. See Figure 9-56. Figure 9-56. Removing Fan. Remove Flywheel 1. Use a flywheel strap wrench or holding tool (see Section 2) to hold the flywheel and loosen the hex.

  • Page 169: Oil Pump Assembly

    Section 9 Disassembly Figure 9-59. Removing Backing Plates and Stator Wire Bracket. 2. Remove the two hex. head screws and stator. See Figure 9-60. Note the routing of the stator lead in the channel. Figure 9-60. Removing Stator. Remove Closure Plate Assembly 1.

  • Page 170: Remove Camshaft

    Remove Camshaft 1. Remove the camshaft and shim. See Figure 9-64. Figure 9-64. Removing Camshaft (Note Shim). Remove Connecting Rods with Pistons and Rings 1. Remove the two hex. flange screws securing the closest connecting rod end cap. Remove the end cap.

  • Page 171: Remove Crankshaft

    Section 9 Disassembly Remove Crankshaft 1. Carefully pull the crankshaft from the crankcase. See Figure 9-68. Note thrust washers and shims if used. Figure 9-68. Removing Crankshaft. Remove Governor Cross Shaft 1. Remove the hitch pin and plain washer, or the retainer and nylon washer, from the governor cross shaft.

  • Page 172: Section 10 Inspection And Reconditioning

    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 & External Governor, Section 5 Ignition, Charging &...
  • Page 173 Procedure to Install New Plug: 1. Use a single cylinder camshaft pin, Kohler Part No. 47 380 09-S as a driver and tap the plug into the plug bore until it seats at the bottom of the bore.
  • Page 174 Check the size frequently. Inspection and Reconditioning NOTE: Kohler pistons are custom-machined to exacting tolerances. When oversizing a cylinder, it should be machined exactly 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.) over the new diameter (Section 1).

  • Page 175: Cylinder Head And Valves

    Replace the flywheel, the crankshaft, and the key if flywheel key is sheared or the keyway is damaged. Inspect the ring gear for cracks or damage. Kohler does not provide the ring gear as a serviceable part. Replace the flywheel if the ring gear is damaged.
  • Page 176 EXHAUST VALVE Dimension Seat Angle 89° 36.987/37.013 mm (1.4562/1.4572 in.) Insert O.D. 4 mm (0.1575 in.) Guide Depth 7.038/7.058 mm (0.2771/0.2779 in.) Guide I.D. 33.37/33.63 mm (1.3138/1.3240 in.) Valve Head Diameter 45° Valve Face Angle 1.5 mm (0.0591 in.) Valve Margin (Min.) 6.982/7.000 mm (0.2749/0.2756 in.) Valve Stem Diameter Figure 10-6.
  • Page 177 Section 10 Inspection and Reconditioning Normal: Even after 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.
  • Page 178 Excessive Combustion Temperatures: The white deposits seen here indicate very high combustion temperatures, usually due to a lean fuel mixture. Gum: Gum deposits usually result from using stale gasoline. 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.

  • Page 179: Pistons And Rings

    Section 10 Inspection and Reconditioning Valve Guides If a valve guide is worn beyond specifications, it will not guide the valve in a straight line. This may result in burnt valve faces or seats, loss of compression, and excessive oil consumption. To check valve guide-to-valve stem clearance, thoroughly clean the valve guide and, using a split-ball gauge, measure the inside diameter of the guide.
  • Page 180 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.
  • Page 181 Section 10 Inspection and Reconditioning Replacement pistons are available in STD bore size, and in 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize. Replacement pistons include new piston ring sets and new piston pins. Replacement ring sets are also available separately for STD, 0.25 mm (0.010 in.), and 0.50 mm (0.020 in.) oversize pistons.

  • Page 182: Hydraulic Lifters

    Check the base surface of the hydraulic lifters for wear or damage. If the lifters need to be replaced, apply a liberal coating of Kohler lubricant 25 357 14-S to the base of each new lifter before it is installed.

  • Page 183: Oil Pump Assembly

    Section 10 Inspection and Reconditioning Disassembly The governor gear must be replaced once it is removed from the closure plate. NOTE: The governor gear is held onto the shaft by small molded tabs in the gear. When the gear is removed from the shaft, these tabs are destroyed and the gear must be replaced.
  • Page 184 Relief Valve Figure 10-16. Oil Pump, Oil Pickup, and One-Piece Relief Valve (Later Style). Inspection Inspect the oil pump housing, gear, and rotors for nicks, burrs, wear, or any visible damage. If any parts are worn or damaged, replace the oil pump. Inspect the oil pressure relief valve piston.
  • Page 185 Section 10 Inspection and Reconditioning 10.14...

  • Page 186: Section 11 Reassembly Ch18

    General NOTE: Make sure the engine is assembled using all specified torque values, tightening sequences and clearances. Failure to observe specifications could cause severe engine wear or damage. Always use new gaskets. Make sure all traces of any cleaner are removed before the engine is assembled and placed into operation.

  • Page 187: Install Governor Cross Shaft

    Section 11 Reassembly Figure 11-2. Installing Oil Seal. Install Governor Cross Shaft 1. Lubricate the governor cross shaft bearing surfaces in the crankcase with engine oil. 2. Slide the small lower washer onto the governor cross shaft and install the cross shaft from the inside of the crankcase.

  • Page 188: Install Connecting Rods With Pistons And Rings

    Figure 11-7. Installing Crankshaft. Install Connecting Rods with Pistons and Rings NOTE: The cylinders are numbered on the crankcase. Make sure to install the piston, connecting rod and end cap into its appropriate cylinder bore as previously marked at disassembly. Do not mix the end caps and connecting rods.

  • Page 189: Install Camshaft

    6. Repeat the above procedure for the other connecting rod and piston assembly. Install Camshaft 1. Liberally apply camshaft lubricant (Kohler Part No. 25 357 14-S) to each of the cam lobes. Lubricate the camshaft bearing surfaces of the crankcase and the camshaft with engine oil.
  • Page 190 Figure 11-14. Checking Camshaft End Play. 3. Apply pressure on the camshaft end play checking tool (pushing camshaft toward crankshaft). Use a feeler gauge to measure the camshaft end play between the shim spacer and the checking tool. Camshaft end play should be 0.076/0.127 mm (0.003/0.005 in.).

  • Page 191: Install Closure Plate Assembly

    Section 11 Reassembly Thrust Shim Needle Thrust Bearing Bearing Race Closure Plate Figure 11-17. Correct Sequence of Thrust Bearing, Washer and Shim in Closure Plate. The race for the thrust bearing presses loosely into the closure plate. If it is not already installed, push it into the crankshaft bore inside the closure plate.
  • Page 192 3. Apply a 1.5 mm (1/16 in.) bead of sealant to the sealing surface of the closure plate. See Figure 11-19 for sealant pattern. Figure 11-19. Closure Plate Sealant Pattern. 4. Make sure the end of the governor cross shaft is lying against the bottom of cylinder 1 inside the crankcase.

  • Page 193: Install Flywheel

    Section 11 Reassembly Figure 11-23. Torquing Stator Screws. 4. Route the stator leads in the crankcase channel, then install the backing plates and the stator wire bracket (if used). Secure using the four hex. flange screws. See Figures 11-24 and 11-25. Torque the screws to 7.3 N·m (65 in.
  • Page 194 Figure 11-28. Carefully Align Keyway to Key. NOTE: Make sure the flywheel key is installed properly in the keyway. The flywheel can become cracked or damaged if the key is not properly installed. 1. Install the woodruff key into the keyway of the crankshaft.
  • Page 195 Install Hydraulic Lifters 1. See ‘‘Servicing Hydraulic Lifters’’ in Section 10 for lifter preparation (bleed down) procedures. 2. Apply camshaft lubricant (Kohler Part No. 25 357 14-S) to the bottom surface of each lifter. See Figure 11-34. Lubricate the hydraulic lifters and the lifter bores in the crankcase with engine oil.

  • Page 196: Valve Stem Seals

    Figure 11-36. Match Numbers on Cylinder Barrel and Head. Figure 11-37. Intake Valve Seal Location. Valve Stem Seals These engines use valve stem seals on the intake valves and occasionally on the exhaust valves. Always use a new seal whenever the valve is removed or if the seal is deteriorated or damaged in any way.
  • Page 197 Section 11 Reassembly Heads secured with hex. flange screws: 2. Install a new cylinder head gasket, (with printing up). Figure 11-40. Always Use New Head Gaskets. NOTE: Match the numbers embossed on the cylinder heads and crankcase. See Figure 11-36. 3.

  • Page 198: Install Push Rods And Rocker Arms

    Figure 11-43. Installing New Mounting Studs to Specified Height. 4. Check that the dowel pins are in place and install a new cylinder head gasket (printing up). 5. Install the cylinder head. Match the numbers on the cylinder heads and the crankcase. See Figure 11-36.

  • Page 199: Install Ignition Modules

    Section 11 Reassembly 5. Repeat the above steps for the remaining cylinder. Do not interchange parts from the cylinder heads. Figure 11-47. Using Spanner Wrench to Lift Rocker Arm Over Push Rod. 6. Rotate the crankshaft to check for free operation of the valve train.

  • Page 200: Install Intake Manifold

    , reattach the leads and seal the ™ base of the terminal connectors with GE/ Novaguard G661 (Kohler Part No. 25 357 11-S) or Fel-Pro Lubri-Sel dielectric compound. The beads should overlap between the terminals* to form a solid bridge of compound.
  • Page 201 Section 11 Reassembly Figure 11-54. Connecting Kill Leads on Standard Ignition Modules. Figure 11-55. Connect Leads on SMART-SPARK Ignition Modules. Install Breather Cover and Inner Baffles RTV sealant was used on early models between the breather cover and the crankcase. A gasket with imprinted sealant beads is now used and recommended.
  • Page 202 Figure 11-58. Installing Screws (Locations 3 and 4). 7. Install the inner baffles using the two remaining hex. flange screws (see Figures 11-59 and 11-60) and finger tighten. Do not torque the screws at this time; they will be tightened after the blower housing and outer baffles are installed.
  • Page 203 Section 11 Reassembly 4. If the rectifier-regulator was not removed, attach the ground wire or metal grounding bracket for the rectifier-regulator, using the silver colored screw and washer, to the lower blower housing hole. See Figure 11-63. Figure 11-63. Ground Lead Details. 5.
  • Page 204 Figure 11-67. Breather Cover Fastener Torque Sequence. Reconnect Rectifier-Regulator 1. Install the rectifier-regulator in the blower housing, if removed previously, then connect the rectifier- regulator ground lead with the washer and silver screw through the eyelet as shown in Figure 11-68.
  • Page 205 Section 11 Reassembly Cylinder Baffle Mounting Location Blower Housing Mounting Location Figure 11-71. Reinstalling SAM Module. Install Electric Starter Motor 1. Install the starter motor using the two hex. flange screws. See Figure 11-72. Some inertia-drive starters have a pinion cover and spacers on the starter bolts.

  • Page 206: Install Carburetor

    Metal-Cased Pulse Fuel Pump Plastic-Cased Pulse Fuel Pump Figure 11-74. Reinstalled Fuel Pump. Install Carburetor WARNING: Explosive Fuel! Gasoline may be present in the carburetor and fuel system. Gasoline is extremely flammable and its vapors can explode if ignited. Keep sparks and other sources of ignition away from the engine.
  • Page 207 Section 11 Reassembly 2. Make sure the throttle linkage is connected to the governor lever and the throttle lever on the carburetor. 3. Move the governor lever toward the carburetor as far as it will go (wide-open throttle) and hold in position.
  • Page 208 3. Connect the governor spring from the main control bracket to the appropriate hole in the governor lever as indicated in the following charts. Note that hole positions are counted from the pivot point of the governor lever. See Figure 11-82 and the appropriate chart.
  • Page 209 Section 11 Reassembly 8 mm Governor Lever and Hole Position/RPM Charts Governor Lever CH18 Engines Intended Maximum RPM Governor Shaft Configuration High Idle 3744 Needle Bearing 3120 3888 3780 3672 3564 Standard 3456 (Parent Material) 3348 3240 3132 3024 CH20-740 Engines Intended Maximum RPM Governor Shaft...
  • Page 210 Item Description Bracket, speed control Clamp, cable (some applications) Kill Switch (some applications) Lever, choke (top position) Lever, throttle control (middle) Linkage, choke control Lever, throttle actuator (bottom) Screw, M5x0.8x20 Washer, wave Washer, flat (3) Spring, choke return Nut, M5x0.8 lock Figure 11-83.

  • Page 211: Install Valve Covers

    Section 11 Reassembly Install Valve Covers Three valve cover designs have been used. The earliest type used a gasket and RTV sealant between the cover and sealing surface of the cylinder head. The second type had a black O-Ring installed in a groove on the underside of the cover and may have metal spacers in the bolt holes.

  • Page 212: Install Muffler

    Figure 11-87. Connecting Fuel Inlet Line. 2. Position a new gasket and the air cleaner base while carefully pulling the loose end of the rubber breather hose through the base until properly seated (collars sealed against each side of base). See Figure 11-88.
  • Page 213 Section 11 Reassembly Install Oil Cooler 1. Reinstall the oil cooler on the engine (if equipped). Install a new gasket between the cooler and the closure plate. Torque nipple adapter to 27 N·m (20 ft. lb.). See Figure 11-92. Figure 11-92. Torquing Oil Filter Nipple. Install Oil Filter and Fill Crankcase with Oil 1.
  • Page 214 Figure 11-96. Reinstall the Dipstick in Tube. 6. Make sure the O-Ring is in place then reinstall the oil fill cap on the valve cover. See Figure 11-97. Figure 11-97. Reinstalling Oil Fill Cap (Some Models). Connect Spark Plug Leads 1.
  • Page 215 Section 11 Reassembly 11.30...

  • Page 216: Section 12 Ch18-745 Clutch

    Clutch General Some engines are equipped with a “wet” disc type clutch. See Figure 12-1 for exploded view of clutch. Shifting Lever Gasket Seal Shaft (Yoke) Adjusting Ring Driven Member Release Sleeve Bearing Release Assembly Figure 12-1. Wet Type Clutch - Exploded View. Section 12 Clutch Nameplate...
  • Page 217 Section 12 Clutch Service On this type, an oil “splash” type lubrication system is used. The proper oil level must be maintained to provide efficient lubrication. The oil should be changed after each 100 hours of operation. When refilling, use 0.47 L (1 pt.) of motor oil of proper viscosity.
  • Page 218 FOR SALES AND SERVICE INFORMATION IN U.S. AND CANADA, CALL 1-800-544-2444 ENGINE DIVISION, KOHLER CO., KOHLER, WISCONSIN 53044 FORM NO.: TP-2428-B ISSUED: 4/92 REVISED: 6/04 MAILED: 7/04 LITHO IN U.S.A.

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