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Kohler Aegis LH685, Service Manual

The Kohler Aegis LH685 service manual is a comprehensive guide to help you properly maintain and repair your engine. This manual includes step-by-step instructions, diagrams, and troubleshooting tips to ensure your engine runs smoothly. Download the free manual from manualshive.com and keep your engine in top condition.

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5B.1

Section 5B

EFI Fuel System

5B

LH760

Section 5B

Electronic Fuel Injection (EFI)

Fuel System

Contents

Page(s)

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) & “Auto-Learn” Initialization Procedure ........................................... 5B.6-5B.8
Engine (Coolant) Temperature Sensor ............................................................................................ 5B.8-5B.9
Oxygen Sensor ............................................................................................................................. 5B.9-5B.11
Electrical Relay .......................................................................................................................... 5B.11-5B.12
Fuel Injectors ............................................................................................................................. 5B.12-5B.15
Ignition System .......................................................................................................................... 5B.15-5B.16
Spark Plugs .......................................................................................................................................... 5B.16
Wiring Harness ..................................................................................................................................... 5B.16
Battery Charging System ...................................................................................................................... 5B.16

Fuel Components

Fuel Pump ................................................................................................................................. 5B.16-5B.17
Fuel Pressure Regulator ............................................................................................................ 5B.17-5B.18
Fuel Filter ............................................................................................................................................. 5B.19
Fuel Rail ............................................................................................................................................... 5B.19
Fuel Line ............................................................................................................................................... 5B.19
Throttle Body/Intake Manifold Assembly ............................................................................................... 5B.20
Idle Speed Adjustment (RPM) ............................................................................................................... 5B.20
Initial Governor Adjustment ........................................................................................................ 5B.20-5B.22

Troubleshooting

Electrical System ...................................................................................................................... 5B.22-5B.25
Fuel System ......................................................................................................................................... 5B.26
Fault Codes ............................................................................................................................... 5B.26-5B.33
Troubleshooting Flow Chart ........................................................................................................ 5B.33-5B.34
Flow Chart Diagnostic Aids ........................................................................................................ 5B.35-5B.36
Common Complaints/Problems ................................................................................................. 5B.36-5B.37

Not For Resale 

www.SmallEngineDiscount.com

Summary of Contents for Aegis LH685

Page 1: ...AEGIS LH630 LH685 LH750 LH760 SERVICE MANUAL LIQUID COOLED HORIZONTAL CRANKSHAFT Not For Resale www SmallEngineDiscount com...

Page 2: ...on 5 Fuel System and Governor Section 5B Electronic Fuel Injection EFI Fuel System Section 6 Lubrication System Section 7 Cooling System Section 8 Electrical System and Components Section 9 Disassembl...

Page 3: ...lure to follow these precautions could result in injury to yourself and others LH630 LH685 LH750 LH760 Rotating Parts can cause severe injury Stay away while engine is in operation WARNING Rotating Pa...

Page 4: ...lames and other sources of ignition away from the battery at all times Keep batteries out of the reach of children Remove all jewelry when servicing batteries Before disconnecting the negative ground...

Page 5: ...The engine identification numbers appear on a decal or decals affixed to the engine The primary location is on the side of the flywheel cover See Figure 1 1 Placement may vary due to OEM requirements...

Page 6: ...water contains a high mineral content Propylene glycol based antifreeze is not recommended This mixture will provide protection from 37 C 34 F to 108 C 226 F For protection and use outside the indicat...

Page 7: ...efore 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 Maintenance Schedule These required maintenan...

Page 8: ...he equipment and or engine as a reminder to refill the cooling system before starting 4 The fuel system must be completely emptied or the gasoline must be treated with a stabilizer to prevent deterior...

Page 9: ...e Key 5 8 18 UNF Thread 7 16 20 Thread Option 120 96 4 762 Coolant Overflow Fill 39 00 1 535 Oil Fill 119 78 4 716 673 70 26 524 Overall Fuel Pump 440 00 17 323 2X 184 20 7 252 127 90 5 035 C L Mounti...

Page 10: ...0 69 mm 2 7 in Displacement LH630 624 cc 38 1 cu in LH685 674 cc 41 1 cu in LH750 LH760 748 cc 45 6 cu in Compression Ratio LH630 LH685 8 5 1 LH750 LH760 8 7 1 Dry Weight LH630 LH685 LH750 51 7 kg 114...

Page 11: ...02 0 0248 in Connecting Rod to Piston Pin Running Clearance 0 015 0 028 mm 0 0006 0 0011 in Piston Pin End I D New 17 015 17 023 mm 0 6699 0 6702 in Max Wear Limit 17 036 mm 0 6707 in Crankcase Govern...

Page 12: ...LH630 77 000 77 025 mm 3 0315 3 0325 in LH685 80 000 80 025 mm 3 1496 3 1506 in LH750 LH760 83 006 83 031 mm 3 2679 3 2689 in Max Wear Limit LH630 77 063 mm 3 0340 in LH685 80 065 mm 3 1522 in LH750 L...

Page 13: ...Wear Limit 7 936 mm 0 3124 in Governor Gear Shaft O D New 5 990 6 000 mm 0 2358 0 2362 in Max Wear Limit 5 977 mm 0 2353 in Governor Gear Shaft to Governor Gear Running Clearance 0 090 0 160 mm 0 0035...

Page 14: ...n LH750 LH760 0 012 0 039 mm 0 0004 0 0015 in Oil Control Ring to Groove Side Clearance LH630 0 046 0 196 mm 0 0018 0 0077 in LH685 0 046 0 196 mm 0 0018 0 0077 in LH750 LH760 0 026 0 176 mm 0 0010 0...

Page 15: ...ase Running Clearance 0 0124 0 0501 mm 0 0005 0 0020 in Intake Valve Stem to Valve Guide Running Clearance 0 038 0 076 mm 0 0015 0 0030 in Exhaust Valve Stem to Valve Guide Running Clearance 0 050 0 0...

Page 16: ...1 7 15 2 9 26 4 1 36 5 0 44 2 0 18 M5 2 5 22 3 2 28 5 8 51 8 1 72 9 7 86 4 0 35 M6 4 3 38 5 7 50 9 9 88 14 0 124 16 5 146 6 8 60 M8 10 5 93 13 6 120 24 4 216 33 9 300 40 7 360 17 0 150 Tightening Tor...

Page 17: ...40 7 30 3 8 16 47 5 35 67 8 50 3 8 24 54 2 40 81 4 60 7 16 14 47 5 35 74 6 55 108 5 80 7 16 20 61 0 45 101 7 75 142 4 105 1 2 13 67 8 50 108 5 80 155 9 115 1 2 20 94 9 70 142 4 105 223 7 165 9 16 12 1...

Page 18: ...er KO3219 Ignition System Tester KO1047 Amp Meter KO3218 Inductance Tachometer KO3216 Camshaft Seal Protector KO1070 Phone 1 800 533 0492 International 1 507 455 7223 8 00 am 8 00 pm EST Fax 1 800 578...

Page 19: ...tite Instant Gasket Aerosol 25 597 07 S NOTE Always use fresh sealant Using outdated sealant can result in leakage The aerosol canister has a month year date code on the top The sealant is generally g...

Page 20: ...tarts Hard 1 PTO drive is engaged 2 Dirt or water in the fuel system 3 Clogged fuel line 4 Loose or faulty wires or connections 5 Faulty choke or throttle controls 6 Faulty spark plugs 7 Low compressi...

Page 21: ...debris on these areas are causes of higher operating temperatures and overheating Check for obvious fuel oil and coolant leaks or damaged components Excessive oil leakage can indicate a clogged or im...

Page 22: ...engine side should be a minimum of 10 2 cm 4 in above the level in the open side If the level in the engine side is less than specified low no vacuum or the level in the engine side is lower than the...

Page 23: ...do not attach it to the tester at this time 5 Connect an adequate air source to the tester 6 Turn the regulator knob in the increase clockwise direction until the gauge needle is in the yellow set ar...

Page 24: ...gure 4 3 Air Cleaner Element with Inner Element Air Cleaner Element Service Every 250 hours of operation more often under extremely dusty or dirty conditions replace the paper element and cylindrical...

Page 25: ...e air cleaner hose is securely clamped to both the air cleaner outlet and the inlet elbow on the carburetor Air Cleaner Mounting Base Make sure the base is securely fastened to the upper valve cover s...

Page 26: ...here the fuel is mixed with air This fuel air mixture is then burned in the engine combustion chamber Fuel Recommendations General Recommendations Purchase gasoline in small quantities and store in cl...

Page 27: ...ckup screen in line filter shut off valve and fuel line Correct any observed problem and reconnect the line 4 Check the operation of fuel pump a Remove the fuel line from the inlet fitting of carburet...

Page 28: ...sion and valve is open 5 Position the new gasket onto the new cover fuel pump assembly and install onto cylinder head Align the air cleaner mounting bracket holes with the upper two valve cover screw...

Page 29: ...the correct kit number Fuel Shut Off Solenoid Most carburetors are equipped with a fuel shut off solenoid The solenoid has a spring loaded pin that retracts when 12 volts is applied to the lead When...

Page 30: ...on 3 Set the low idle speed to 1200 RPM 75 RPM by turning the low idle speed adjusting screw in or out Check the speed using a tachometer NOTE The actual low idle speed depends on the application Refe...

Page 31: ...crew b Low idle fuel mixture circuit blocked restricted Clean carburetor as required 1 Engine starts hard runs roughly or stalls at idle speed 2 Engine runs rich indicated by black sooty exhaust smoke...

Page 32: ...ed Inspect the carburetor body for cracks holes and other wear or damage Inspect the float for cracks holes and missing or damaged float tab Check the float hinge and pin for wear or damage Inspect th...

Page 33: ...7 If proper float height adjustment cannot be achieved check to see if the fuel inlet needle is dirty obstructed or worn Remove the brass screw and float assembly to remove the fuel inlet needle Figur...

Page 34: ...e 10 Idle Fuel Adjusting Needle 11 Main Jet 12 Solenoid Seat 13 Fuel Shut off Solenoid Kit 14 Idle Speed Adjusting Screw 15 Jet Accelerator Pump Carburetor only 16 Accelerator Pump Cover 17 Diaphragm...

Page 35: ...e Parts Manual for the engine being serviced to ensure the correct repair kits and replacement parts are ordered Carburetor Repair Kit Contains Float Kit Contains High Altitude 1500 Meter Kit Contains...

Page 36: ...outward as speed increases Governor spring tension moves them inward as speed decreases Figure 5 7 Governor Linkage As the flyweights move outward they cause the regulating pin to move outward The re...

Page 37: ...t and rotate the shaft counterclockwise as far as it will turn then tighten hex nut securely Sensitivity Adjustment Governor sensitivity is adjusted by repositioning the governor spring in the holes o...

Page 38: ...gh Speed Lever Stop Screw Do Not Remove High Speed Adjusting Screw High Speed Control Lever Choke Control Cable Throttle Control Cable Z Bend Choke Linkage Throttle Control Lever 2 Kill Switch Choke C...

Page 39: ...5B 9 Oxygen Sensor 5B 9 5B 11 Electrical Relay 5B 11 5B 12 Fuel Injectors 5B 12 5B 15 Ignition System 5B 15 5B 16 Spark Plugs 5B 16 Wiring Harness 5B 16 Battery Charging System 5B 16 Fuel Components F...

Page 40: ...e gauge crank the engine in 10 15 second intervals allowing a 60 second cool down period between cranking intervals until the engine starts Description NOTE The number of cranking intervals necessary...

Page 41: ...lve opens the fuel air mixture is drawn into the combustion chamber ignited and burned The ECU controls the amount of fuel injected and the ignition timing by monitoring the primary sensor signals for...

Page 42: ...not charge battery with key switch on Always disconnect negative battery cable lead before charging battery and also unplug harness from ECU before performing any welding on equipment Electrical Comp...

Page 43: ...ear with two consecutive teeth missing is mounted on the flywheel The inductive speed sensor is mounted 1 5 0 25 mm 0 059 0 010 in away from the ring gear During rotation anAC voltage pulse is created...

Page 44: ...problem reconnect the sensor and perform step 5 again Throttle Position Sensor TPS General The throttle position sensor TPS is used to indicate throttle plate angle to the ECU Since the throttle by wa...

Page 45: ...correct position of the TPS is established and set at the factory Do not loosen the TPS or alter the mounting position unless absolutely required by fault code diagnosis or throttle shaft service If t...

Page 46: ...procedure the MIL goes back into blinking 4 consecutive blinks every 2 seconds the engine and Oxygen sensor have cooled down and out of closed loop operation prohibiting the learning from occurring R...

Page 47: ...Using the fuel delivery maps the ECU then knows how much fuel is required for starting at that temperature Service The coolant temperature sensor is a sealed non serviceable assembly A faulty sensor m...

Page 48: ...emperatures to a minimum of 375 C 709 F A cold oxygen sensor will require approximately 1 2 minutes at moderate engine load to warm sufficiently to generate a voltage signal Proper grounding is also c...

Page 49: ...d from pin 20 to the sensor terminal of the main harness Both tests should indicate continuity a If there is no continuity displayed in either of the tests check the harness circuit for breaks or dama...

Page 50: ...mpletes 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 The director pla...

Page 51: ...ch opening The amount of fuel injected is controlled by the ECU and determined by the length of time the valve needle is held open also referred to as the injection duration or pulse width It may vary...

Page 52: ...t the spark plug leads from spark plugs 3 Remove the air cleaner outer cover inner wing nut element cover and air cleaner element precleaner Service the air cleaner components as required 4 Remove the...

Page 53: ...nd blower housing mounting screws to 3 9 N m 35 in lb and the intake manifold and air cleaner mounting screws to 9 9 N m 88 in lb Injector problems due to dirt or clogging are generally unlikely due t...

Page 54: ...nnectors 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 actu...

Page 55: ...l pump 3 If the pump did not activate step 2 disconnect the plug from the fuel pump Connect a DC voltmeter across the terminals in the plug turn on the key switch and observe if a minimum of 7 volts i...

Page 56: ...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...

Page 57: ...crimp the replacement clamps 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 Figure 5B 26 Manifold Assembl...

Page 58: ...rt lower than normal but gradually increase to the established setting as operation continues Do not attempt to circumvent this warm up period or readjust the idle speed during this time The engine mu...

Page 59: ...time If the governor throttle components are all intact but you think there may be a problem with the adjustment follow ProcedureAto check the setting If the governor lever was loosened or removed go...

Page 60: ...lb See Figure 5B 34 Make sure that the governor arm has not twisted up or down after the nut has been tightened Figure 5B 34 Adjusting Governor Shaft 4 Verify that the governor has been set correctly...

Page 61: ...oxidation on the terminals can interfere with the milliamp currents used in system operation Cleaning the connectors and grounds will solve problems in many cases In an emergency situation simply disc...

Page 62: ...ition Sensor TPS Input Speed Sensor Input Speed Sensor Ground Not Used Not Used Not Used Injector 1 Output Injector 2 Output Not Used Diagnostic Line Throttle Position Temperature Sensor Supply Voltag...

Page 63: ...Not For Resale www SmallEngineDiscount com...

Page 64: ...ne connections are good 6 Test fuel pump and relay operation as described earlier under Fuel Pump Service Fault Codes The ECU continuously monitors engine operation against preset performance limits I...

Page 65: ...connect the cable and tighten securely or reinstall the main fuse Start the engine and allow it to run for several minutes The MIL should remain off if the problem was corrected and the fault codes sh...

Page 66: ...Short Circuit to Battery Injector 2 Open Circuit Injector 2 Short Circuit to Ground Injector 2 Short Circuit to Battery MIL Lamp Open Circuit MIL Lamp Short Circuit to Ground MIL Lamp Short Circuit t...

Page 67: ...stem Related a Non resistor spark plug s used Code 22 Source Throttle Position Sensor TPS Explanation Unrecognizable signal is being sent from sensor too high too low inconsistent Expected Engine Resp...

Page 68: ...bably with the oxygen sensor wiring or connectors If the engine is still running rich laboring short on power or lean popping or misfiring the fuel mixture is suspect probably incorrect TPS initializa...

Page 69: ...lated a Sensor connector or wiring problem b Sensor contaminated or damaged c Exhaust leak d Poor ground path e Pin circuit 20 wiring or connectors 3 TPS Sensor Related a Throttle plate position incor...

Page 70: ...s related a Broken or shorted wire in harness ECU pin 14 to injector pin 2 ECU pin 28 to fuel pump relay pin 86 Note After key off then key on code 56 would be set also Fuel pump relay pin 87 to injec...

Page 71: ...en shorted to ground or may be on continuously if shorted to battery Expected Engine Response Engine will not run or fuel pump will continue to run when switch is off Possible Causes 1 Fuel pump relay...

Page 72: ...5B 34 Section 5B EFI Fuel System Operate for an appropriate period of time based upon original fault codes Figure 5B 36 Not For Resale www SmallEngineDiscount com...

Page 73: ...IL Diagnostic Light 14 Code 56 Pump Relay 15 Code 61 End of Fault Blink Code Transmission Diagnostic Aid 3 RUN ON MIL remains on while engine is running Possible causes 1 Fault codes which turn on MIL...

Page 74: ...he most common complaints or problems reported by customers For each problem you will find a list of the most likely causes or areas to be investigated Always start by checking if there are any stored...

Page 75: ...r cleaner 3 Insufficient fuel pressure or fuel delivery 4 Vacuum intake air leak 5 Improper governor setting adjustment or operation 6 Speed sensor malfunction 7 TPS faulty mounting problem or TPS Ini...

Page 76: ...perature at the time of operation as shown in the following table Figure 6 1 Oil Container Logo The top portion of the symbol shows service class such as API SERVICE CLASS SJ The symbol may show addit...

Page 77: ...very 200 hours or annually whichever comes first more often under severe conditions Refill with service class SG SH SJ or higher oil as specified in the Viscosity Grades table on previous page Always...

Page 78: ...eck oil level to assure crankcase oil level is at the F mark on the dipstick Refer to the operating instructions of the equipment this engine powers Because of equipment design or application there ma...

Page 79: ...se breather system is a necessary complement to the lubrication system To help prevent the engine oil from weeping out past shafts seals and gaskets during operation it is desirable to have a low vacu...

Page 80: ...aveling through the engine the coolant from the two separate circuits merges and moves through the intake manifold to the lower side of the thermostat During warm up the thermostat is closed preventin...

Page 81: ...es of the engine as necessary Check the condition of fan assembly and v belt tension Do not operate the engine without all shrouds and protective guards installed Lift the screen vertically to remove...

Page 82: ...Figure 7 7 Figure 7 7 Coolant Drain Plug Oil Filter Side On the starter side it may be preferable to first remove the starter or use a piece of cardboard formed in a V to drain the coolant out over th...

Page 83: ...e Flushing Cooling System NOTE To prevent engine damage do not pour water into a hot engine Do not operate engine without coolant With system properly drained 1 Fill the cooling system with clean wate...

Page 84: ...ich is thought to be the fault of the thermostat it can be checked to determine its operating condition Before removing and testing the thermostat make sure all other possible causes such as debris ac...

Page 85: ...ld is clean 2 Install a new thermostat into the intake manifold so the larger spring end is down into the well of the intake manifold Position a new thermostat gasket on the intake manifold 3 Install...

Page 86: ...ter with the appropriate 45 mm adapter may be used to check the cooling system and the radiator cap A typical tester and adapter is shown in Figure 7 14 Figure 7 14 A Typical Tester and Adapter Test I...

Page 87: ...fore the engine is returned to service If a pressure loss is noted 1 With pressure on the system apply a soap water solution and check all joint connections hoses and cooling system components for ext...

Page 88: ...rst remove the spark plugs check condition and reset the gap or replace with new spark plugs as necessary Every 500 hours of operation replace the spark plugs To service the spark plugs perform the fo...

Page 89: ...e following photos Carbon Fouled Soft sooty black deposits indicate incomplete combustion caused by a restricted air cleaner overrich carburetion weak ignition or poor compression Worn On a worn plug...

Page 90: ...e reach of children Remove all jewelry when servicing batteries Before disconnecting the negative ground cable make sure all switches are OFF If ON a spark will occur at the ground cable terminal whic...

Page 91: ...Violet Diodes Red Eyelet Terminal for Ignition Key Switch or Starter Post White Two electronic capacitive discharge ignition modules which mount on the engine crankcase A kill switch or key switch whi...

Page 92: ...o the system can result Do not crank or run an engine with a spark plug lead disconnected Always provide a path for the spark to discharge to ground D1 C1 T1 Spark Plug P S SCS L2 L1 Reported ignition...

Page 93: ...cedure on the other cylinder Remember to reconnect the first spark plug lead Conclusion Ground Clip Post Terminal Test Procedure for Standard CD Ignition Battery Charging System General These engines...

Page 94: ...Plug 2 Cylinder Spark Plug 1 Cylinder Flywheel Stator Assembly Ignition Module Intake Manifold Screw Blower Housing Safety Switch W Ignition Kill Carburetor Assembly Intake Manifold Screw Fuse Y Grou...

Page 95: ...d on the bracket below the overflow reservoir See Figure 8 8 To replace it disconnect the connector plug and remove the two screws Take off the rectifier regulator NOTE When installing the rectifier r...

Page 96: ...measure AC voltage across stator leads using an AC voltmeter 3a With engine stopped measure the resistance across stator leads using an ohmmeter 3b With the engine stopped measure the resistance from...

Page 97: ...Reassembly Sections for starter removal and installation procedures Use the exploded view Figure 8 21 for reference during the disassembly and reassembly procedure Troubleshooting Guide Starting Diff...

Page 98: ...cap See Figures 8 11 and 8 12 Figure 8 11 Removing Solenoid Screws Solenoids mounted with external Torx head screws may be removed using an E5 Torx socket available through local tool suppliers Figur...

Page 99: ...d drive end cap See Figure 8 16 Figure 8 16 Starter Frame Removal 7 Remove the drive lever pivot bushing and backing plate from the end cap See Figure 8 17 Figure 8 17 8 Take out the drive lever and p...

Page 100: ...Removing Retaining Ring 12 Remove the drive pinion assembly from the armature 13 Clean the parts as required NOTE Do not soak the armature or use solvent when cleaning Wipe clean using a soft cloth or...

Page 101: ...ing Armature 1 Clean and inspect the commutator outer surface The mica insulation of the commutator must be lower than the O D surface undercut to ensure proper operation of the commutator See Figure...

Page 102: ...vice Clean the drive lever and armature shaft Apply Kohler electric starter drive lubricant Part No 52 357 02 S to the lever and shaft Versilube G322L or Mobil Temp SHC 32 Clean and check the other st...

Page 103: ...ion of the drive lever will be flush or below the machined surface of the housing which receives the backup washer See Figure 8 29 Figure 8 29 Installing Armature and Pivot Lever 7 Install the backup...

Page 104: ...ly a Carefully unhook the retaining caps from over each of the brush assemblies Do not lose the springs Figure 8 34 Removing Retaining Caps b Position each of the brushes back in their slots so they a...

Page 105: ...See Figures 8 37 and 8 38 Figure 8 37 Torquing Thru Bolts Figure 8 38 Torquing Brush Holder Screws 13 Hook the plunger behind the upper end of the drive lever and install the spring into the solenoid...

Page 106: ...9 Section 8 Electrical System and Components 8 Figure 8 40 Positive Brush Lead Connection Completed Starter Photo Figure 8 41 Delco Remy Solenoid Shift Starter Not For Resale www SmallEngineDiscount c...

Page 107: ...ched components 8 Remove air cleaner assembly 9 Remove throttle and choke controls 10 Remove external governor controls 11 Remove carburetor and adapter 12 Remove Oil Sentry 13 Remove breather cover 1...

Page 108: ...e the orientation of the cutout The upper screw may also secure a clamp for the stator leads Figure 9 3 Removing the Adapter Plate Screws Drain Coolant from Cooling System 1 Loosen the radiator cap th...

Page 109: ...ove Flywheel Cover Radiator Assembly Mounting Brackets and Attached Components 1 Remove the screws or nuts and flat washers 2 on each side securing the lower flywheel cover to the LH and RH radiator s...

Page 110: ...3 Disconnecting the Rectifier Regulator 7 Remove the four screws securing the LH and RH side mounting brackets to the crankcase Pull the complete mount assembly forward to remove See Figure 9 14 Figur...

Page 111: ...unting bracket for the air cleaner See Figure 9 16 Figure 9 16 Removing Upper Valve Cover Mounting Bracket Screws Figure 9 17 Removing Air Cleaner from Engine Remove Throttle and Choke Controls 1 Remo...

Page 112: ...the Carburetor Mounting Screws Remove Carburetor and Adapter WARNING Explosive Fuel Gasoline is extremely flammable and its vapors can explode if ignited Store gasoline only in approved containers in...

Page 113: ...h and remove the switch from the breather cover See Figure 9 24 Figure 9 24 Oil Sentry Location on Engine Remove Breather Cover 1 Remove the four hex flange screws securing the breather cover to the c...

Page 114: ...ee Figure 9 29 Figure 9 29 Removing Two Lower Valve Cover Screws 2 Remove the valve covers and valve cover gaskets Note on which side the oil fill or fuel pump is located for correct reassembly later...

Page 115: ...performed note the assembly order and position of parts See Figure 9 34 Figure 9 34 Disassembled Fan Assembly Component 2 Remove the two hex flange screws and take off the mounting bracket with the fa...

Page 116: ...ywheel 1 Use a flywheel strap wrench or holding tool see Section 2 to hold the flywheel Remove the hex flange screw and flat washer See Figure 9 38 Figure 9 38 Removing Flywheel Screw and Washer 2 Use...

Page 117: ...e by pass hose from the fitting on the water pump See Figure 9 41 Figure 9 41 Removing By pass Hose from Water Pump Fitting Figure 9 42 Removing the Six Intake Manifold Screws Figure 9 43 Removing the...

Page 118: ...lat washer securing the cogged drive pulley to the camshaft See Figure 9 45 Figure 9 45 Removing Cam Pulley Hardware 2 Carefully lift the pulley off the camshaft and remove the belt from the water pum...

Page 119: ...specific position Do not loosen remove or alter the mounted position of this fitting at any time Contact the factory service department for specific instructions if the fitting is damaged or its mount...

Page 120: ...case unless replacement is intended If studs are removed for any reason discard the old stud s do not reuse reinstall Use new studs and refer to the assembly sequence for proper installation Figure 9...

Page 121: ...t into the perimeter of the closure plate Insert the drive end of a 1 2 breaker bar between the top splitting tab and the crankcase Hold the handle horizontal and pull it toward you to break the RTV s...

Page 122: ...the end cap See Figure 9 61 Figure 9 61 Removing Connecting Rod End Cap NOTE If a carbon ridge is present at the top of either cylinder bore use a ridge reamer tool to remove it before attempting to...

Page 123: ...hrough the inside of the crankcase See Figure 9 65 Figure 9 65 Removing Governor Cross Shaft Remove Governor Cross Shaft 1 Remove the retaining ring and nylon washer from the governor cross shaft See...

Page 124: ...as this will damage the surfaces and could result in leaks Refer to A Guide to Engine Rebuilding TP 2150 for additional information Measurement Guide TP 2159 A and Engine Inspection Data Record TP 243...

Page 125: ...des easy access for cleaning any grinding deposits that may collect in the oil passages High Point From Fillet Intersections The Fillet Must Blend Smoothly With The Bearing Journal Surface Minimum Thi...

Page 126: ...required Honing While most commercially available cylinder hones can be used with either portable drills or drill presses the use of a low speed drill press is preferred as it facilitates more accura...

Page 127: ...ur of operation after a rebuild The final cleaning operation should always be a thorough scrubbing with a brush and hot soapy water Use a strong detergent that is capable of breaking down the machinin...

Page 128: ...stems in guides See Figure 10 5 for valve details and specifications Figure 10 5 Valve Details A B C D E F G H Seat Angle Insert O D Guide Depth Guide I D Valve Head Diameter Valve Face Angle Valve M...

Page 129: ...hours under controlled test conditions Bad Condition The valve depicted here should be replaced Note the warped head margin damaged and too narrow These conditions could be attributed to excessive hou...

Page 130: ...is repeatedly stopped before it has a chance to reach normal operating temperatures Replace corroded valves Excessive Combustion Temperatures The white deposits seen here indicate very high combustio...

Page 131: ...n the engines but can be reconditioned if not too badly pitted or distorted If cracked or badly warped the cylinder head should be replaced Recondition the valve seat inserts following the instruction...

Page 132: ...l control is also lost when ring gaps are not staggered during installation When cylinder temperatures get too high lacquer and varnish collect on pistons causing rings to stick which results in rapid...

Page 133: ...iddle Compression Ring End Gap LH630 New Bore Top Ring 0 180 0 380 mm 0 0071 0 0150 in Middle Ring 0 250 0 450 mm 0 0098 0 0177 in Used Bore Max 0 77 mm 0 030 in LH685 New Bore Top Ring 0 180 0 430 mm...

Page 134: ...ction 1 Specifications Tolerances and Special Torque Values Replace rod and cap if scored or excessively worn Service replacement connecting rods are available in STD crankpin size and 0 25 mm 0 010 i...

Page 135: ...p 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 oil pump Reassembly 1 Install the oil pump body to the clo...

Page 136: ...nst an O Ring outside the perimeter of the recess See Figure 10 17 2 0 mm 0 0787 in Governor Cross Shaft Seal Figure 10 17 Water Pump The impeller assembly is not serviceable but it should be inspecte...

Page 137: ...or shaft must rotate smoothly without noticeable bearing play wobble or binding 3 Check the v belt for excessive wear cracking or damage If proper belt tension cannot be obtained or the condition of t...

Page 138: ...nt subsections 1 Install flywheel end oil seal and camshaft seal 2 Install governor cross shaft 3 Install crankshaft 4 Install connecting rods with pistons and rings 5 Install camshaft 6 Check camshaf...

Page 139: ...ee Figure 11 2 Do not bottom the seal in the bore or the oil passage may be obstructed Install Governor Cross Shaft 1 Lubricate the governor cross shaft bearing surfaces in the crankcase with engine o...

Page 140: ...n rings in the grooves until the end gaps are 120 apart The oil ring rails should also be staggered Cylinder 1 Cylinder 2 Figure 11 6 Piston Connecting Rod and End Cap Detail 2 Lubricate the cylinder...

Page 141: ...e over the keyway is also recommended See Figure 11 10 Figure 11 10 Installing Camshaft using Seal Protector 2 Lubricate the camshaft bearing surfaces of the crankcase and camshaft with engine oil App...

Page 142: ...assembly is located inside the closure plate If service was required and the governor was removed refer to the assembly procedures under Governor Assembly in Section 10 Thrust Bearing Washer and Shim...

Page 143: ...l 0 043 in RED 1 2938 1 3700 mm 1 3319 mm Nominal 0 052 in Remove the closure plate If end play requires adjustment remove the original shim and install the appropriate size replacement Install Closur...

Page 144: ...nkcase If a thick flat washer was used on one of the screws install it in the 10 location Install the silver plated ground screw in its original location normally the 4 or 6 location Torque the fasten...

Page 145: ...ading in the studs use a steady tightening motion without interruption until the proper height is obtained The frictional heat from the engaging threads may otherwise cause the locking compound to set...

Page 146: ...in Figure 11 26 Figure 11 26 Breather Cover Fastener Torque Sequence 7 Install the pipe plug or Oil Sentry switch as equipped into the tapped breather port if removed earlier Apply pipe sealant with...

Page 147: ...fore valves are installed in the cylinder head Also replace the seals if they are deteriorated or damaged in any way Never reuse an old seal See Figure 11 30 Figure 11 30 Cylinder Head Showing Intake...

Page 148: ...er head gasket See Figure 11 33 NOTE Match numbers embossed on cylinder heads and crankcase Figure 11 33 Installing Head Gasket 4 Install the 1 cylinder head onto the 1 side mounting studs See Figure...

Page 149: ...hout interruption until the proper torque is achieved The frictional heat from the engaging threads may otherwise cause the locking compound to set prematurely If new screws are not available apply Lo...

Page 150: ...ivalent to the threads and reinstall the plugs Torque the plugs to 13 5 N m 120 in lb See Figure 11 41 Figure 11 41 Installing Coolant Drain Plugs Install Water Pump Drive Belt and Transfer Tube Assem...

Page 151: ...l amount of grease in several locations to hold the new water pump O Ring in place Install a new O Ring in the groove of crankcase See Figures 11 45 and 11 46 Do not use RTV sealant in place of the O...

Page 152: ...those of the first clamp See Figure 11 48 Figure 11 48 Transfer Tube Hose and Water Pump asAssembly 7 Holding the pump assembly elevated assemble the transfer tube to the 90 fitting in the crankcase a...

Page 153: ...and hose section have not been pulled up Figure 11 53 Torquing the Hex Cap on Fitting After Pump Installation 10 Install the drive belt onto the cogged pulley of water pump then around the cam pulley...

Page 154: ...in their appropriate locations Make sure the clamps for the wiring harness are positioned on the long screw on each side Torque the six intake manifold mounting screws in two steps initially to 7 4 N...

Page 155: ...ifold The notch in manifold gasket and thermostat housing must all be aligned Install and torque the two hex flange screws to 9 9 N m 88 in lb See Figure 11 61 Figure 11 61 Torquing Thermostat Housing...

Page 156: ...ition the clamp for the stator leads on the upper screw See Figure 11 64 Torque the screws to 15 3 N m 135 in lb Figure 11 64 Installing Starter Adapter 2 Place the stator leads within the clamp and c...

Page 157: ...ure that the key is properly seated and parallel with the shaft See Figure 11 67 NOTE Make sure the flywheel key is installed properly in the keyway The flywheel can become cracked or damaged if the k...

Page 158: ...ne of the ignition modules 4 Insert a 0 25 mm 0 010 in flat feeler gauge or shim stock between the magnet and ignition module Loosen the hex flange screws enough to allow the magnet to pull the module...

Page 159: ...ate using the two hex flange screws NOTE The stator leads and rectifier regulator plug must be above the starter 2 Make sure the starter is square to the flywheel and torque the two hex flange screws...

Page 160: ...ing to the carburetor if disconnected previously then install the carburetor onto the intake manifold Install and torque the two mounting screws to 9 9 N m 88 in lb See Figures 11 80 and 11 81 Figure...

Page 161: ...nnect the throttle link to governor lever with the plastic bushing Hook the dampening spring into the small middle hole Figure 11 85 Installing Connecting Governor Linkage 2 Move the governor lever TO...

Page 162: ...e shoulder of the flywheel hub and the adjacent face surface are clean and free of any nicks or damage 2 Install the crankshaft pulley adapter onto the flywheel hub so the offset for the pulley is out...

Page 163: ...oned within the cutout in the intake manifold as shown in Figure 11 93 Be careful not to pinch the harness wires between the bracket and intake manifold when tightening Figure 11 92 Installing Upper P...

Page 164: ...40 in lb Install the fan and pulley assembly onto the fan shaft and upper mounting bracket 7 Apply Loctite No 242 to the front threads of the fan shaft Install the flat washer and the hex flange nut t...

Page 165: ...s sequence to 24 3 N m 215 in lb Figure 11 100 Torquing Lower Pulley Screws 9 Mount the RH and LH lower radiator supports with cross support bracket attached to the crankcase using the four hex flange...

Page 166: ...ed install the rain cap and secure with the clamp Check the position of the dust ejector it should face downward Adjust the end cap position as required See Figure 11 108 Figure 11 108 Dust Ejector Va...

Page 167: ...h the fan blades as radiator is installed Figure 11 111 Setting Radiator Assembly into Place 4 Position the upper radiator support brackets on top of the air cleaner mounting bracket Install and finge...

Page 168: ...lb See Figures 11 115 and 11 116 Figure 11 115 Fan Clearance Checking Figure 11 116 Torquing Side Support Screws 7 Hold the radiator assembly in position then torque the screws securing the two upper...

Page 169: ...l the remaining two screws or nuts and flat washers Torque the four fasteners to 9 9 N m 88 in lb See Figure 11 120 Figure 11 120 Torquing Lower Screws and Rectifier Regulator Mounting 4 If removed mo...

Page 170: ...t to drain into the lower areas Fill the overflow reservoir midway between the FULL and ADD marks then install the radiator and reservoir caps See Figures 11 123 and 11 124 Figure 11 123 Radiator Cap...

Page 171: ...n 5 Place the throttle control into the idle or slow position and check the low idle speed RPM Refer to Section 5 if adjustment is required 6 Stop the engine 7 Recheck the oil and coolant levels Oil l...

Page 172: ...A FORMNO TP 2527 ISSUED 9 03 REVISED MAILED 10 03 ENGINE DIVISION KOHLER CO KOHLER WISCONSIN 53044 FOR SALESAND SERVICE INFORMATION IN U S AND CANADA CALL 1 800 544 2444 Not For Resale www SmallEngine...

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