Kohler Aegis LH630 Service Manual

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Owner's manual (21 pages)

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LH630, LH640, LH685, LH690, LH750, LH755

Service Manual

IMPORTANT:

Read all safety precautions and instructions carefully before operating equipment. Refer to operating

instruction of equipment that this engine powers.

Ensure engine is stopped and level before performing any maintenance or service.

Safety

Maintenance

Specifications

Tools and Aids

Troubleshooting

Air Cleaner/Intake

Fuel System

Governor System

Lubrication System

Electrical System

Starter System

Cooling System

Disassembly/Inspection and Service

Reassembly

66 690 01 Rev. A

KohlerEngines.com

Table of Contents

Summary of Contents for Kohler Aegis LH630

Page 1 LH630, LH640, LH685, LH690, LH750, LH755 Service Manual IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating instruction of equipment that this engine powers. Ensure engine is stopped and level before performing any maintenance or service.
Page 2: Safety Precautions
Safety SAFETY PRECAUTIONS WARNING: A hazard that could result in death, serious injury, or substantial property damage. CAUTION: A hazard that could result in minor personal injury or property damage. NOTE: is used to notify people of important installation, operation, or maintenance information. CAUTION WARNING WARNING...
Page 3: Maintenance Instructions
Perform these procedures more frequently under severe, dusty, dirty conditions. REPAIRS/SERVICE PARTS Kohler genuine service parts can be purchased from Kohler authorized dealers. Find your local Kohler Engines dealer at KohlerEngines.com or call 1-800-544-2444 (U.S.A. and Canada). 66 690 01 Rev. A...
Page 4: Oil Recommendations
OIL RECOMMENDATIONS STORAGE If engine will be out of service for 2 months or more We recommend use of Kohler oils for best performance. follow procedure below. Other high-quality detergent oils (including synthetic) of API (American Petroleum Institute) service class SJ 1.
Page 5: Specifications
Specifications Engine Dimensions Dimensions in millimeters. Inch equivalents shown in (). 440.00 Oil Filter Side (17.323) Rain Cap Removal (0.906) Optional Oil Fill Fuel Pump 673.70 (26.524) Overall 622.54 (24.509) Overall without Rain Cap 152.08 (5.987) Drain 38.00 2X 184.20 (1.496) (7.252) 143.25...
Page 6: Engine Identification Numbers
Kohler engine identification numbers (model, specification and serial) should be referenced for efficient repair, ordering correct parts, and engine replacement. Model ..... LH630 Liquid Cooled...
Page 7: Clearance Specifications
Specifications TORQUE SPECIFICATIONS LH630 LH640 LH685 LH690 LH750 LH755 Electric Starter Starter Thru Bolt 5.6-9.0 N·m (49-79 in. lb.) Starter Mounting Screw 15.3 N·m (135 in. lb.) Starter Brush Holder Fastener 2.5-3.3 N·m (22-29 in. lb.) Starter Solenoid Fastener 4.0-6.0 N·m (35-53 in. lb.) Starter Solenoid Positive (+) Brush Lead Retaining Nut 8.0-11.0 N·m (71-97 in.
Page 8 Specifications CLEARANCE SPECIFICATIONS LH630 LH640 LH685 LH690 LH750 LH755 Connecting Rod Connecting Rod-to-Crankpin Running Clearance 0.043/0.068 mm (0.0016/0.0026 in.) Max. Wear Limit 0.083 mm (0.0032 in.) Connecting Rod-to-Crankpin Side Clearance 0.26/0.63 mm (0.0102/0.0248 in.) Connecting Rod-to-Piston Pin Running Clearance 0.015/0.028 mm (0.0006/0.0011 in.) Crankcase Governor Cross Shaft Bore I.D.
Page 9 Specifications CLEARANCE SPECIFICATIONS LH630 LH640 LH685 LH690 LH750 LH755 Governor Governor Cross Shaft to Crankcase Running 0.025/0.126 mm (0.0009/0.0049 in.) Clearance Governor Cross Shaft O.D. 7.949/8.000 mm (0.3129/0.3149 in.) Max. Wear Limit 7.936 mm (0.3124 in.) Governor Gear Shaft O.D.
Page 10 Specifications CLEARANCE SPECIFICATIONS LH630 LH640 LH685 LH690 LH750 LH755 Piston, Piston Rings, and Piston Pin cont. Piston Thrust Face-to-Cylinder Bore Running 0.014/ 0.019/ 0.015/ Clearance 0.057 mm 0.062 mm 0.058 mm (0.0005/ (0.0007/ (0.005/ 0.0022 in.) 0.0024 in.) 0.0022 in.)
Page 11: General Torque Values
Specifications GENERAL TORQUE VALUES English Fastener Torque Recommendations for Standard Applications Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 or 5 Fasteners Into Aluminum Size Grade 2 Grade 5 Grade 8 Tightening Torque: N·m (in. lb.) ± 20% 8-32 2.3 (20) 2.8 (25)
Page 12: Tools And Aids
Here is a list of tools and their source. SEPARATE TOOL SUPPLIERS Kohler Tools SE Tools Design Technology Inc. Contact your local Kohler source of 415 Howard St. 768 Burr Oak Drive supply. Lapeer, MI 48446 Westmont, IL 60559...
Page 13 For reaming worn valve guides to accept replacement oversize valves. Can be used in low-speed drill press or with handle below for hand reaming. Reamer Handle Design Technology Inc. For hand reaming using Kohler 25 455 12-S reamer. DTI-K830 Valve Guide Service Kit (Courage, Aegis, Command, OHC) SE Tools KLR-82415 For servicing worn valve guides.
Page 14 Tools and Aids FLYWHEEL HOLDING TOOL ROCKER ARM/CRANKSHAFT TOOL A flywheel holding tool can be made out of an old junk A spanner wrench to lift rocker arms or turn crankshaft flywheel ring gear and used in place of a strap wrench. may be made out of an old junk connecting rod.
Page 15: Troubleshooting Guide
Troubleshooting TROUBLESHOOTING GUIDE When troubles occur, be sure to check 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 and vary by engine specification. Use these to locate causing factors.
Page 16 Troubleshooting EXTERNAL ENGINE INSPECTION Engine Loses Power NOTE: It is good practice to drain oil at a location away ● Dirty air cleaner element. from workbench. Be sure to allow ample time for ● Engine overheated. complete drainage. ● Excessive engine load. ●...
Page 17: Crankcase Vacuum Test
Troubleshooting CRANKCASE VACUUM TEST WARNING WARNING Carbon Monoxide can cause severe nausea, Rotating Parts can cause severe injury. fainting or death. Stay away while engine is in operation. Avoid inhaling exhaust fumes. Engine exhaust gases contain poisonous carbon Keep hands, feet, hair, and clothing away from all monoxide.
Page 18: Compression Test
Troubleshooting COMPRESSION TEST For Command Twins: A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plug(s) before removing them. Be sure choke is off, and throttle is wide open during test. Compression should be at least 160 psi and should not vary more than 15% between cylinders.
Page 19: Air Cleaner/Intake
Air Cleaner/Intake AIR CLEANER BREATHER TUBE These systems are CARB/EPA certified and components Ensure both ends of breather tube are properly should not be altered or modified in any way. connected. AIR COOLING Heavy-Duty Air Cleaner Components WARNING Hot Parts can cause severe burns. Do not touch engine while operating or just after stopping.
Page 20: Fuel Pump
3. Reconnect fuel lines to inlet and outlet fittings and Low permeation fuel line must be installed on carbureted secure with clamps. Kohler Co. engines to maintain EPA and CARB regulatory compliance. FUEL SYSTEM TESTS When engine starts hard or turns over but will not start, fuel system might be causing problems. Test fuel system by performing following tests.
Page 21 Fuel System CARBURETOR Engines in this series are equipped with emission compliant fixed main jet carburetors, manufactured by Keihin. All have self-relieving chokes for efficient WARNING operation. Depending on specifications and application Explosive Fuel can cause fires and severe involved, most will also contain a fuel shut-off solenoid burns.
Page 22 Fuel System Troubleshooting-Carburetor Related Causes Condition Possible Cause Conclusion Engine starts hard, runs rough, or Low idle fuel mixture (some models)/ Adjust low idle speed tab, then adjust stalls at idle speed. speed improperly adjusted. low idle fuel needle. Engine runs rich (indicated by black, Clogged air cleaner.
Page 23 Fuel System Slow and Mid-Range Low Idle Fuel Adjustment At low speeds engine operates only on slow circuit. As Optimum Low Idle Fuel Setting a metered amount of air is drawn through slow air bleed jets, fuel is drawn through main jet and further metered through slow jet.
Page 24 Do not fill fuel tank while engine is hot or 1219 meters (4000 ft.). To obtain high altitude kit running. information or to find a Kohler authorized dealer visit KohlerEngines.com or call1-800-544-2444 (U.S. and Gasoline is extremely flammable and its vapors can Canada).
Page 25: Governor System
Governor System GOVERNOR Governor Adjustments Engine is equipped with a centrifugal flyweight NOTE: Do not tamper with governor setting. Overspeed mechanical governor. It is designed to hold engine speed is hazardous and could cause personal injury. constant under changing load conditions. Governor gear/ Initial Adjustment Procedure flyweight mechanism is mounted inside closure plate Make this adjustment whenever governor lever is...
Page 26: Lubrication System
Lubrication System This engine uses a full pressure lubrication system. This system delivers oil under pressure to crankshaft, camshaft and connecting rod bearing surfaces. In addition to lubricating bearing surfaces, lubrication system supplies oil to hydraulic valve lifters. A high-efficiency gerotor pump is located in closure plate. Oil pump maintains high oil flow and oil pressure, even at low speeds and high operating temperatures.
Page 27 Lubrication System 9. Dispose of used oil and filter in accordance with local ordinances. OIL SENTRY (if equipped) ™ This switch is designed to prevent engine from starting in a low oil or no oil condition. Oil Sentry may not shut ™...
Page 28: Electrical System
Electrical System SPARK PLUGS Normal CAUTION Electrical Shock can cause injury. Do not touch wires while engine is running. Spark Plug Component and Details Plug taken from an engine operating under normal conditions will have light tan or gray colored deposits. If center electrode is not worn, plug can be set to proper gap and reused.
Page 29 Electrical System Carbon Fouled ELECTRONIC IGNITION SYSTEMS Ignition System Components Soft, sooty, black deposits indicate incomplete combustion caused by a restricted air cleaner, over rich Kill Switch/ carburetion, weak ignition, or poor compression. Off Position of Air Gap Key Switch Overheated Flywheel Magnet...
Page 30 Electrical System Wiring Diagram-15/20/25 Amp Regulated Battery Charging System with Fixed Timing KohlerEngines.com 66 690 01 Rev. A...
Page 31 Electrical System Accessory (Yellow) Battery (Red) Starter (Blue/Red) Run (Red) Key Switch Ground Ignition Kill (White) Ground Starter (Black) Battery Accessory Key Switch Ignition Kill Yellow Connector Starter Solenoid Stud Starter Solenoid Tang Starter Assembly Fuse Intake Manifold Black White Carburetor Screw Regulator Recifier (15...
Page 32: Battery Charging System
Electrical System Test for Spark NOTE: If 2 testers are available, testing can be performed simultaneously for both cylinders. However, if only 1 tester is available, 2 individual tests must be performed. Side not being tested must have spark plug lead connected or grounded.
Page 33 Electrical System Condition Conclusion 20/25 amp 15 amp OK (green) light comes on and stays steady. Disconnect tester black lead Part is good and may be used. attached to 1 AC terminal and reconnect it to other AC terminal. Repeat test. If OK (green) light comes on again, part is good and may be used.
Page 34: Starter System
Starter System NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool down period between starting attempts. Failure to follow these guidelines can burn out starter motor. NOTE: If engine develops sufficient speed to disengage starter but does not keep running (a false start), engine rotation must be allowed to come to a complete stop before attempting to restart engine.
Page 35 Starter System Solenoid Shift Starter Components Starter Disassembly NOTE: Do not reuse old retainer. NOTE: Do not soak armature or use solvent when cleaning. Wipe clean using a soft cloth, or use compressed air. 1. Remove hex nut and disconnect positive (+) brush lead/bracket from solenoid terminal.
Page 36 4 brushes and springs are serviced as a set. Use a new holes in metal clips must be up/out. Slide brush Kohler brush and spring kit if replacement is necessary. holder assembly down into place around commutator, and install positive (+) brush lead 1.
Page 37 Starter System c. Install brush springs and snap on retainer caps. 12. Install thru bolts and brush holder mounting screws. Torque bolts to 5.6-9.0 N·m (49-79 in. lb.) and brush d. Hold starter assembly vertically on end housing, holder mounting screws to 2.5-3.3 N·m (22-29 in. and carefully place tool (with extension) and lb.).
Page 38: Cooling System
Cooling System WARNING Liquid coolant can get extremely hot from operation. Turning radiator cap when engine is hot can allow steam Hot liquid can cause severe burns. and scalding liquid to blow out and burn you severely. Shut off machine. Only remove radiator cap when cool enough Do not loosen radiator cap while engine is to touch with bare hands.
Page 39 Do not operate engine without proper tension cannot be established by coolant. repositioning of lower pulley shims. Use only Kohler With system properly drained: Part No. 66 203 02-S belt if replacement is necessary.
Page 40 Use only Kohler Part No. 66 203 02-S belt. DO NOT use a substitute belt. To Test Remove thermostat from system. Hang or suspend...
Page 41 Cooling System 6. Check thermostat, and pressure test radiator cap. 2. Remove dipstick and check appearance of oil in crankcase. Another method would be to remove an 7. Make sure water pump and drive belt are oil drain plug and drain a small amount of oil for operational.
Page 42: Disassembly/Inspection And Service
Disassembly/Inspection and Service External Engine Components Dipstick Electric Starter Adapter Plate Oil Drain Plug Flywheel Cover Radiator Drain Plug Clean all parts thoroughly as engine is disassembled. Disconnect Spark Plug Leads Only clean parts can be accurately inspected NOTE: Pull on boot only, to prevent damage to spark and gauged for wear or damage.
Page 43 Disassembly/Inspection and Service Remove Starter and Adapter Plate External Engine Components 1. Disconnect leads attached to starter solenoid terminals. 2. Remove screws securing starter to adapter plate. 3. Remove screws attaching adapter to crankcase. Note orientation of cutout. Upper screw may also secure a clamp for stator leads.
Page 44 Disassembly/Inspection and Service 7. Remove four screws securing LH and RH side Remove Carburetor and Adapter mounting brackets to crankcase. Pull complete mount assembly forward to remove. WARNING 8. Further disassembly for component servicing may be performed as required. Explosive Fuel can cause fires and severe burns.
Page 45 Disassembly/Inspection and Service External Engine Components Oil Sentry Breather Cover Gasket Fiber Filter ™ Breather Reed Fan Mounting Adapter Plate Carburetor Assembly Bracket Fan Belt Bearing Pulley Pulley Half Spacer Shims Adapter 66 690 01 Rev. A KohlerEngines.com...
Page 46 If proper belt tension cannot be obtained, or condition of belt is suspect; replace it with Kohler Remove Fan Assembly, Mounting Bracket, and Fan Part No. 66 203 02-S. Do not use a substitute belt.
Page 47 2. Rotate flywheel, so magnet is away from ignition is damaged. modules. Inspect ring gear for cracks or damage. Kohler does 3. Remove mounting screws and take off each ignition not provide ring gears as a serviceable part. Replace module.
Page 48 Disassembly/Inspection and Service 4. Inspect and, if necessary, separate transfer tube and Remove Intake Manifold, Thermostat Housing, By- hose section from water pump. Remove hose pass Hose and Wiring Harness clamps, noting their size differences and position of 1. Disconnect by-pass hose from fitting on water pump. tangs.
Page 49 NOTE: It is not necessary to remove cylinder studs from damage. If lifters need to be replaced, apply a liberal crankcase unless replacement is intended. If coating of Kohler lubricant to base of each new lifter studs are removed for any reason, discard old before it is installed.
Page 50: Exhaust Valve
Disassembly/Inspection and Service 2. Lay a rag or shop towel on table of drill press and 1. Remove screws, rocker arms pivots and rocker arms place lifter, open end up, on towel. from cylinder head(s). 3. Lower chucked push rod until it contacts plunger in 2.
Page 51 Disassembly/Inspection and Service After cleaning, check flatness of cylinder head and Valve Seat Inserts corresponding top surface of crankcase, using a surface Hardened steel alloy intake and exhaust valve seat plate or piece of glass and feeler gauge. Maximum inserts are press fitted into cylinder head. Inserts are allowable out of flatness is 0.076 mm (0.003 in.).
Page 52 Disassembly/Inspection and Service Crankcase Components Locking Tab Thrust Oil Seal Governor Gear Shaft Governor Gear Washer Regulating Pin Camshaft Gerotor Oil Pump Assembly Nipple Oil Filter Crankshaft Governor Cross Shaft Piston Pin Retainer Piston Pin Connecting Rod Piston Piston Ring Set Inspection Remove Closure Plate Inspect oil seal in closure plate and remove it if it is worn...
Page 53 Disassembly/Inspection and Service Governor Gear Assembly Oil Pump Assembly Governor Shaft Press Depth Details Oil Pump Torque Sequence Oil pump is mounted inside of closure plate. If service is required, refer to these following service procedures Disassembly Gear Shaft 1. Remove screws. 19.40 mm (0.7638 in.) 2.
Page 54 Disassembly/Inspection and Service 5. After torquing, rotate gear and check for freedom of Piston and Rings Components and Details movement. Make sure there is no binding. If binding occurs, loosen screws, reposition pump, retorque screws and recheck movement. Remove Camshaft Remove camshaft and shims.
Page 55 Disassembly/Inspection and Service When cylinder temperatures get too high, lacquer and 3. Top compression ring (top groove): Install top ring varnish collect on pistons causing rings to stick, which using a piston ring expender. Make sure results in rapid wear. A worn ring usually takes on a identification mark is up or dye colored stripe (if shiny or bright appearance.
Page 56 Disassembly/Inspection and Service Inspect crankshaft keyways. If they are worn or chipped, Governor Cross Shaft Oil Seal replacement of crankshaft will be necessary. Cross Shaft Oil Seal Details Inspect crankpin for score marks or metallic pickup. Slight score marks can be cleaned with crocus cloth soaked in oil.
Page 57 Disassembly/Inspection and Service Honing Final cleaning operation should always be a thorough scrubbing with a brush and hot, soapy water. Use a Detail strong detergent that is capable of breaking down machining oil while maintaining a good level of suds. If suds break down during cleaning, discard dirty water and start again with more hot water and detergent.
Page 58 Reassembly Crankcase Components Locking Tab Thrust Oil Seal Governor Gear Shaft Governor Gear Washer Regulating Pin Camshaft Gerotor Oil Pump Assembly Nipple Oil Filter Crankshaft Governor Cross Shaft Piston Pin Retainer Piston Pin Connecting Rod Piston Piston Ring Set NOTE: Make sure engine is assembled using all Install Flywheel End Oil Seal and Camshaft Oil Seal specified torque values, tightening sequences 1.
Page 59 Reassembly 3. Lubricate crankshaft journals and connecting rod Install Governor Cross Shaft bearing surfaces with engine oil. 1. Lubricate governor cross shaft bearing surfaces in 4. Make sure FLY stamping on pistons is facing crankcase with engine oil. Apply a small amount of towards flywheel side of engine.
Page 60 Reassembly Oil Pump Assembly Install Closure Plate Oil Seal Oil pump is mounted to inside of closure plate. If Cylinder Head Torque Sequence service was required, and oil pump was removed, refer to assembly procedures under Oil Pump Assembly in Reassembly.
Page 61 Reassembly 6. Install closure plate on crankcase. Carefully seat Install Closure Plate Assembly camshaft and crankshaft into their mating bearings. Rotate crankshaft to help engage oil pump and Closure Plate Sealant Pattern governor gear meshes. 7. Install screws securing closure plate to crankcase. If a thick flat washer was used on one of screws, install it in number 10 location.
Page 62 Reassembly Cylinder Head Components Valve Head Hydraulic Lifter Push Rods Valve Stem Seal Valve Spring Cap Spring Valve Spring Retainers Valve Spring Keepers Rocker Arms Rocker Arm Pivot Rocker Arm Screw Valve Cover Fuel Pump Install Hydraulic Lifters Assemble Cylinder Heads NOTE: Hydraulic lifters should always be installed in Prior to installation, lubricate all components with engine same position as before disassembly.
Page 63 Reassembly 6. Rotate crankshaft to check for free operation of Install Cylinder Heads valve train. Check clearance between valve spring coils at full lift. Minimum allowable clearance is 0.25 Cylinder Head Torque Sequence mm (0.010 in). Install Valve Covers 1. Make sure sealing surfaces of cylinder heads and valve covers are clean and free of all old gasket material.
Page 64 Reassembly NOTE: When installation is complete, tangs of two hose 8. Carefully push water pump down from raised clamps should face outward, away from flywheel position, thereby rotating tube 90° within end and slightly down. connections. Guide pump into position over O-ring; aligning two mounting pins and five screw hole 1.
Page 65 Reassembly Flywheel/ignition/Intake Manifold Components Thermostat Housing Intake Manifold Thermostat Ignition Module Flywheel Stator Torque Sequence 4. Install and tighten pipe plug or temperature warning Install Intake Manifold switch, if removed previously from threaded port of 1. Check that gasket surfaces of intake manifold and intake manifold.
Page 66 Reassembly 8. Position thermostat housing on gasket and intake NOTE: Always use a flywheel strap wrench or holding manifold. Notch in manifold, gasket and thermostat tool to hold flywheel when tightening flywheel housing must all be aligned. Install and torque fastener.
Page 67 Reassembly External Engine Components 1&5 Oil Sentry Breather Cover Gasket Fiber Filter ™ Breather Reed Fan Mounting Adapter Plate Carburetor Assembly Bracket Fan Belt Bearing Pulley Pulley Half Spacer Shims Adapter Torque Sequence Install Spark Plugs Install Reed and Breather Cover Assembly 1.
Page 68 Reassembly 3. Install breather reed and breather reed retainer onto 5. Connect upper end of breather hose to fitting on rear crankcase and secure with screw. Hold assembly in of adapter. line when tightening. Torque screw to 3.9 N·m 6. Connect long end of choke linkage to carburetor. (35 in.
Page 69 Reassembly 1. Make sure shoulder of flywheel hub and adjacent When proper tension is obtained, individually face surface are clean and free of any nicks or remove each capscrew, apply Loctite ® ® damage. threads of lower pulley and reinstall. Torque four bolts in a criss-cross sequence to 24.3 N·m 2.
Page 70 Reassembly 4. Position upper radiator support brackets on top of air Install Radiator Assembly cleaner mounting bracket. Install and finger tighten 1. Reassemble components of radiator assembly, four mounting screws. including upper and lower radiator hoses. Rubber 5. Connect upper and lower radiator hoses to inlets of lubricant may be applied to inner surfaces of hoses radiator and water pump.
Page 71 Reassembly 8. If securing upper brackets to top radiator mounts Install Oil Filter and Fill Crankcase with Oil were loosened, torque to 9.9 N·m (88 in. lb.). NOTE: Make sure both oil drain plugs are installed and 9. If a pulse style fuel pump is used, install it to tapped torqued to specifications to prevent oil leakage.

This manual is also suitable for:

Aegis lh640 Aegis lh685 Aegis lh690 Aegis lh750 Aegis lh755

Kohler Aegis LH630 Service Manual

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