This document is a service manual for Kohler SH Series, Kohler 3000 Series, and Kohler Courage engines, specifically models SH255, SH265, and SH270. It provides comprehensive information for maintenance, troubleshooting, disassembly, inspection, service, and reassembly of these engines.
Function Description:
These engines are designed to power various equipment, and the manual emphasizes the importance of reading safety precautions and instructions before operation and maintenance. The engine's function relies on a fuel system, governor system, lubrication system, electrical system, and starter system, all of which are detailed for service.
Important Technical Specifications:
The manual includes detailed specifications for the engines, covering dimensions, torque values, and clearance specifications.
- Engine Dimensions: Detailed diagrams with measurements in both millimeters and inches are provided for various engine components, including overall dimensions, spark plug location, oil fill, drain plug, and air cleaner removal clearances.
- Engine Identification Numbers: Information on model, specification, serial, and factory codes is included for proper identification and ordering of parts.
- General Specifications (SH255, SH265, SH270):
- Bore: 68 mm (2.7 in.)
- Stroke: 54 mm (2.1 in.)
- Displacement: 195 cc (12.0 cu. in.)
- Oil Capacity (refill): 0.6 L (0.63 U.S. qt.)
- Maximum Angle of Operation (@ full oil level): 25°
- Torque Specifications (SH255, SH265, SH270):
- Air Cleaner Mounting Screw (into intake manifold): 8 N·m (70.8 in. lb.)
- Blower Housing and Sheet Metal M6 Shoulder Screw/M6 Nut: 10 N·m (88.5 in. lb.)
- Carburetor Stud/Primary Nut/Secondary Nut/Intake Cover Nut: 10 N·m (88.5 in. lb.) / 10 N·m (88.5 in. lb.) / 10 N·m (88.5 in. lb.) / 4 N·m (35.4 in. lb.)
- Connecting Rod Cap Fastener (torque in increments): 12 N·m (106 in. lb.)
- Crankcase Oil Drain Plug/Closure Plate Screw: 18 N·m (13 ft. lb.) / 24 N·m (212 in. lb.)
- Cylinder Head Fastener (torque in 2 increments): First to 12 N·m (106 in. lb.), finally to 24 N·m (212 in. lb.)
- Flywheel Retaining Nut: 74 N·m (655 in. lb.)
- Fuel Tank Mounting Nut/Mounting Screw/Inlet Fitting: 24 N·m (212 in. lb.) / 24 N·m (212 in. lb.) / 1.5 N·m (13.3 in. lb.)
- Governor Arm Nut/Throttle Control Lever Nut: 10 N·m (88.5 in. lb.) / 4.5-6 N·m (40-53 in. lb.)
- Ignition Spark Plug/Module Fastener/Module Screw/Oil Sentry™ Module Screw: 27 N·m (20 ft. lb.) / 8 N·m (70.8 in. lb.) / 10 N·m (88.5 in. lb.) / 8 N·m (70.8 in. lb.)
- Muffler M6 Exhaust Screw/M6 Muffler Shield Screw/M4 Muffler Shield Screw/M5 Spark Arrestor Screw: 24 N·m (212 in. lb.) / 8 N·m (70.8 in. lb.) / 2 N·m (17.7 in. lb.) / 3.5 N·m (31 in. lb.)
- Retractable Starter Cover Screw/Screw: 5.4 N·m (47.8 in. lb.) / 10 N·m (88.5 in. lb.)
- Rocker Arm Stud/Pivot Jam Nut: 13.6 N·m (120 in. lb.) / 10 N·m (88.5 in. lb.)
- Valve Cover Fastener: 8 N·m (70.8 in. lb.)
- Clearance Specifications (SH255, SH265, SH270):
- Camshaft End Play: New: 0.025/0.602 mm (0.0010/0.0237 in.), Max. Wear Limit: 0.016/0.052 mm (0.0006/0.0020 in.)
- Bore I.D.: New: 14.000/14.018 mm (0.5512/0.5519 in.), Max. Wear Limit: 14.048 mm (0.5531 in.)
- Connecting Rod Crankpin I.D. @ 21°C (70°F): New: 30.021/30.026 mm (1.1819/1.1821 in.), Max. Wear Limit: 30.08 mm (1.184 in.)
- Connecting Rod-to-Crankpin Running Clearance: New: 0.041/0.051 mm (0.002/0.002 in.), Max. Wear Limit: 0.12 mm (0.005 in.)
- Connecting Rod-to-Crankpin Side Clearance: New: 0.58/0.60 mm (0.023/0.024 in.), Max. Wear Limit: 1.10 mm (0.043 in.)
- Connecting Rod-to-Piston Pin Running Clearance: New: 0.01/0.027 mm (0.0004/0.0011 in.)
- Piston Pin End I.D. @ 21°C (70°F): New: 18.010/18.015 mm (0.709/0.709 in.), Max. Wear Limit: 18.08 mm (0.712 in.)
- Crankcase Governor Cross Shaft Bore I.D.: New: 6.000/6.018 mm (0.2362/0.2369 in.), Max. Wear Limit: 6.037 mm (0.2377 in.)
- Crankshaft End Play (free): New: 0.025/0.703 mm (0.0010/0.028 in.), Ball Bearing: 0.003/0.25 mm (0.0001/0.010 in.)
- Bore (in crankcase) New without Main Bearing: 51.961/51.991 mm (2.0457/2.0469 in.)
- Bore (in closure plate) New without Main Bearing: 51.961/51.991 mm (2.0457/2.0469 in.)
- Flywheel End Main Bearing Journal O.D.: O.D.-New: 24.975/24.989 mm (0.9833/0.9838 in.), O.D.-Max. Wear Limit: 24.95 mm (0.9823 in.), Max. Taper: 0.025 mm (0.0010 in.), Max. Out-of-Round: 0.025 mm (0.0010 in.)
- Closure Plate End Main Bearing Journal O.D.: O.D.-New: 24.975/24.989 mm (0.9833/0.9838 in.), O.D.-Max. Wear Limit: 24.95 mm (0.9823 in.), Max. Taper: 0.025 mm (0.0010 in.), Max. Out-of-Round: 0.025 mm (0.0010 in.)
- Connecting Rod Journal O.D.: O.D.-New: 29.975/29.985 mm (1.1801/1.1805 in.), O.D.-Max. Wear Limit: 29.920 mm (1.1779 in.), Max. Taper: 0.025 mm (0.0010 in.), Max. Out-of-Round: 0.025 mm (0.0010 in.), Width: 25.02/25.08 mm (0.9850/0.9874 in.)
- Runout (either end): 0.025 mm (0.0010 in.)
- Main Bearing I.D. (Crankcase/Closure Plate) New (installed): 24.994/25.000 mm (0.9840/0.9842 in.)
- Cylinder Bore I.D.: New: 70.027/70.035 mm (2.757/2.757 in.), Max. Wear Limit: 70.200 mm (2.764 in.), Max. Out-of-Round: 12.7 microns (0.0005 in.), Max. Taper: 12.7 microns (0.0005 in.)
- Cylinder Head Max. Out-of-Flatness: 0.1 mm (0.0039 in.)
- Governor Cross Shaft-to-Crankcase Running Clearance: 0.013/0.075 mm (0.0005/0.0029 in.)
- Governor Cross Shaft O.D.: New: 5.95/5.98 mm (0.2342/0.2354 in.), Max. Wear Limit: 5.85 mm (0.2303 in.)
- Governor Gear Shaft-to-Governor Gear Running Clearance: 0.09/0.19 mm (0.0035/0.0074 in.)
- Governor Gear Shaft O.D.: New: 6.028/6.043 mm (0.2373/0.2379 in.), Max. Wear Limit: 6.018 mm (0.2369 in.)
- Ignition Spark Plug Gap: 0.76 mm (0.030 in.)
- Module Air Gap: 0.254 mm (0.0100 in.)
- Piston-to-Piston Pin Running Clearance: 0.009/0.016 mm (0.0003/0.0006 in.)
- Piston Pin Bore I.D.: New: 18.004/18.005 mm (0.7088/0.7089 in.), Max. Wear Limit: 18.05 mm (0.7106 in.)
- Piston Pin O.D.: New: 17.992/17.995 mm (0.7083/0.7084 in.), Max. Wear Limit: 17.95 mm (0.7067 in.)
- Top and Center Compression Ring Side Clearance (New Bore/Used Bore max.): 0.04 mm (0.002 in.) / 0.15 mm (0.006 in.)
- Top and Center Compression Ring End Gap (New Bore/Used Bore max.): 0.325 mm/0.4 (0.013/0.016 in.) / 1.00 mm (0.039 in.)
- Top and Center Compression Ring Width (New Bore/Used Bore max.): 1.5/1.51 mm (0.059/0.059 in.) / 1.37 mm (0.054 in.)
- Oil Control Ring-to-Groove Side Clearance: 0.06/0.18 mm (0.0023/0.0071 in.)
- Piston Thrust Face O.D.: New: 67.975/67.985 mm (2.6762/2.6766 in.), Max. Wear Limit: 67.85 mm (2.6712 in.)
- Piston Thrust Face-to-Cylinder Bore Running Clearance (New): 0.057/0.075 mm (0.0022/0.0029 in.)
- Intake Valve Lash: 0.1 mm (0.0040 in.)
- Exhaust Valve Lash: 0.15 mm (0.0060 in.)
- Intake Valve Stem-to-Valve Guide Running Clearance: 0.020/0.044 mm (0.008/0.0017 in.)
- Exhaust Valve Stem-to-Valve Guide Running Clearance: 0.030/0.054 mm (0.0011/0.0021 in.)
- Intake Valve Stem O.D. (New/Max. Wear Limit): 5.480 mm (0.2157 in.) / 5.32 mm (0.2094 in.)
- Exhaust Valve Stem O.D. (New/Max. Wear Limit): 5.47 mm (0.2153 in.) / 5.305 mm (0.2088 in.)
- Intake Valve Stem to Guide (New/Max. Wear Limit): 0.024/0.039 mm (0.001/0.002 in.) / 0.10 mm (0.0004 in.)
- Exhaust Valve Stem to Guide (New/Max. Wear Limit): 0.098/0.112 mm (0.0038/0.0044 in.) / 0.12 mm (0.0005 in.)
- Valve Guide Reamer Size (Standard Intake/Standard Exhaust): 5.506 mm (0.2168 in.) / 5.506 mm (0.2168 in.)
- Valve Seat Width: 0.800/2.00 mm (0.0315/0.787 in.)
- Nominal Valve Face Angle: 30°, 45°, 60°
Usage Features:
The manual provides instructions for various operational aspects and troubleshooting.
- Fuel Recommendations: Specifies the use of clean, fresh, unleaded gasoline with an octane rating of 87 (R+M)/2 or higher, and a research octane number (RON) of 90 octane minimum. It also allows for up to 10% ethyl alcohol or 15% MTBE/unleaded gasoline blend. It warns against using leaded gasoline, adding oil to gasoline, overfilling the fuel tank, or using gasoline older than 30 days.
- Storage: Provides steps for preparing the engine for storage, including adding fuel treatment, changing oil, and disconnecting the battery.
- Troubleshooting Guide: Offers a comprehensive guide for diagnosing common engine problems such as cranking but not starting, starting but not keeping running, hard starting, not cranking, running but missing, not idling, overheating, and knocking. It also covers engine loses power, excessive oil use, oil leaks, and crankcase vacuum issues.
- High Altitude Operation: Advises on the requirement for a high altitude carburetor kit if operating above 4000 ft (1219 meters) and warns against operating with the wrong engine configuration at altitude.
- Governor System: Explains the function of the mechanical governor system, which maintains constant engine speed under varying load conditions. It details how centrifugal force, flyweights, and governor spring tension interact to regulate the throttle plate.
- Initial Governor Adjustment Procedure: Provides step-by-step instructions for adjusting the governor lever and shaft to ensure proper throttle linkage and speed control.
- Testing Engine: Recommends operating the engine on a test stand or bench before installation. It specifies adjusting low-speed idle to 1800 RPM (± 150) and high-speed stop to 3850 + 100 RPM.
Maintenance Features:
The manual outlines a detailed maintenance schedule and procedures for various engine components.
- Maintenance Schedule:
- After first 5 Hours: Change oil (Lubrication System).
- Every 50 Hours or Annually: Service/replace dual-element precleaner (Air Cleaner/Intake).
- Every 100 Hours or Annually (or more frequently under severe conditions): Clean low-profile air cleaner element, replace dual-element air cleaner element, change oil, clean cooling areas, clean spark arrestor (if equipped), replace fuel filter (if equipped).
- Every 100 Hours (Kohler authorized dealer service): Check and adjust valve clearance when engine is cold (Reassembly).
- Every 125 Hours or Annually: Replace spark plug and set gap (Electrical System).
- Every 200 Hours (Kohler authorized dealer service): Replace fuel line (Fuel System).
- Every 300 Hours: Replace low-profile air cleaner element (Air Cleaner/Intake).
- Oil Recommendations: Recommends Kohler oils for best performance and specifies suitable SAE viscosity grades (5W-30, 10W-30, SAE 30) based on ambient air temperature.
- Air Cleaner/Intake: Provides instructions for servicing dual-element and low-profile air cleaners, including cleaning/replacing precleaners and paper/foam elements. Emphasizes proper connection of the breather tube.
- Fuel System: Details the typical carbureted fuel system components and provides instructions for fuel shut-off, fuel filter replacement, and troubleshooting the fuel system. It includes a detailed troubleshooting checklist for carburetor issues.
- Lubrication System: Describes the splash lubrication system and provides oil recommendations and procedures for checking and changing oil. It also covers the Oil Sentry™ system (if equipped).
- Electrical System: Covers spark plugs, electronic ignition system, and battery maintenance. It includes detailed tests for the electronic ignition system and Oil Sentry™ to diagnose electrical issues.
- Starter System: Provides troubleshooting for starting issues and instructions for servicing retractable starters, including rope replacement and pawls/drive replacement.
- Cleaning Engine: Emphasizes thorough cleaning of all parts during disassembly and reassembly, warning against the use of certain cleaners and ensuring all traces are removed.
- Crankcase Vacuum Test: Explains how to test crankcase vacuum using a manometer or vacuum/pressure gauge to diagnose issues like clogged breathers or leaking seals/gaskets.
- Cylinder Leakdown Test: Provides a step-by-step procedure for performing a cylinder leakdown test to check combustion retention and wear of cylinder, piston, rings, or valves.
- Valve Details: Includes detailed specifications for intake and exhaust valves, covering head diameter, stem diameter, valve length, face/seat width, face/seat angle, stem to guide clearance, and valve guide dimensions.
- Piston Ring Installation: Provides instructions for installing new piston rings, emphasizing correct orientation and checking piston-to-bore and piston-to-ring side clearances.
- Tools and Aids: Lists specialized tools required for service, including their descriptions and sources (Kohler Tools, SE Tools, Design Technology Inc.). It also includes instructions for making custom tools like a flywheel holding tool and a rocker arm/crankshaft tool from old parts.
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