KOHLERGNGINes SERVICE MANUAL OHC 16,18 HP Horizontal CrankshaftContents Section 1. Safety and General Information Section 2. Special Tools Section 3. Troubleshooting. Section 4. Air Cleaner and Air Intake System... Section 5. Fuel System and Governor Section 6. Lubrication System Section 7. Retractable Starter ... Section 8. Electrical System and Components .. Section 9. Disassembly Section 10. Inspection and Reconditioning .. Section 11. Reassembly ..TH16 & TH18 Section 1 Safety and General Information Safety Precautions ‘To insure safe operations 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. AB warnins 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. Bd caution Caution is used to indicate the presence of a hazard that will or can cause minor personal injury or property damage if the warning is ignored. NOTE Note is used to notify people of installation, operation, or maintenance information that is important but not hazard-related. For Your Safety! These precautions should be followed at al times. Failure to follow these precautions could result in injury to yourself and others. 4 WARNING & WARNING 4 WARNING aX ‘Accidental Starts can cause severe injury or death. Disconnect and ground spark plug leads before servicing, Rotating Parts can cause severe injury. Stay away while engine isin operation, lor just after stopping [Hot Parts can cause severe burns, Do not touch engine while operating Accidental Starts! Before servicing the engine or equipment, always disconnect the spark plug leads to prevent the ‘engine from starting accidentally. Ground the leads to prevent sparks that could cause fires. Make sure the equipment is in neutral Rotating Parts! Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate the engine with covers, shrouds, or guards removed. Hot Parts! Engine components can get extremely hot from operation. To prevent severe burns, do not touch these areas while the engine is running-or immediately afer it is turned off. Never operate the engine with heat shields or guards removed. 14Section 1 Safety and General Information A. WARNING & WARNING 4 WARNING [Explosive Fuel can cause fires and| /severe burns. [Stop engine before filing fuel tank ‘Carbon Monoxide can cause severe nausea, fainting, or death, Do not operate engine in closed or confined area, Explosive Gas can cause fires and] severe acid burns. Charge battery only in a well ventilated area. Keep sources of ignition away. 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. Do rot fill the fuel tank while the engine is hot or running, since spilled fuel could ignite itt comes in contact with hot parts or sparks from ignition, Do not start the engine near spilled fuel. Never use gasoline as a cleaning agent. Lethal Exhaust Gases! Engine exhaust gases contain poisonous carbon monoxide. Carbon monoxide is odorless, coloriess, and can cause death if inhaled. Avoid inhaling exhaust fumes, and never run the engine in a closed building or confined area, 4 WARNING 4 WARNING i) [Cleaning Solvents can cause [severe injury or death. Use oniy in well ventilated areas jaway from ignition sources, [Uncolling Spring can cause severe injury. Wear safety goggles or face protection when servicing retractable starter. Flammable Solvents! Carburetor cleaners and solvents are extremely flammable, Keep sparks, flames, and other sources of ignition away from the area. Follow the cleaner manufacturer's warnings and instructions on its proper and safe use. Never use ‘gasoline as a cleaning agent. ‘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 "Retractable Starter" Section 7 for relieving spring tension. Explosive Gas! Batteries produce explosive hydrogen gas while being charged. To prevent a fire or explosion, charge batteries only in well ventilated areas. Keep ‘sparks, open flames, 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 cable, make sure all switches are OFF. If ON, a spark will occur at the ground cable terminal, which could cause an explosion if hydrogen gas or gasoline vapors are present. & CAUTION 2 Electrical Shock can cause injury. Do not touch wires while engine is running, Electrical Shock! Never touch electrical wires or components while the engine is running. They can be sources of electrical shock. 12Section 1 Safety and General Information 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 41-1. An explanation of these numbers is shown in. Identification Decal Figure 1-2. Figure 1-1. Engine Identification Decal Location. ‘A. Model No. THI6 ‘Twin Cylinder Engine ee Horizontal Crankshaft__________| | |_version Code Horsepower J electric Start Spec. No. 52501, Engine Model Code aa $$$ tion of Code Mode! it Ge ban Basic Engine 54 THIB Cc. Serial No. 2605810332, Year Manufactured ———____1 ———Factory Code 26 1996 27 1997 28 1998, 23 1999 30 2000 Figure 1-2. Explanation of Engine Identification Numbers. 13Section 1 Safety and General Information Oil Recommendations Using the proper type and weight of oi in the crankcase is extremely important. So is checking oil daily and changing oil regularly. Failure to use the correct oil, or using dirty oil, causes premature engine wear and failure Oil Type Use high-quality detergent oll of API (American Petroleum institute) Service class SG or SH. Select the viscosity based on the air temperature at the time of operation as shown in the following table. RECOMMENDED SAE VISCOSITY GRADES J] TTEWPSRATURE PANGE BCE Use of synthetic ol having SW-20 or SW-30 rating is acceptable, up to 40°F. *Symhetc ols wil provide better starting in extreme cold (oclow -10°F) NOTE: Using other than service class SG or SH oil or extending oil change intervals longer than recommended can cause engine damage. ‘A logo or symbol on oil containers identities the API service class and SAE viscosity grade. See Figure 1-3. Figure 1-3. Oil Container Logo. Refer to Section 6 - “Lubrication System” for detailed procedures on checking the oll, changing the oil, and changing the oil fier. Fuel Recommendations Bd was: expiosive Fue Gasoline is extremely lammable and its vapors can explode ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, aay rom sparks or ames. Do not fil the ful tank hile the engine s hot or running, since spilled fil could gnite fit comes in contact wth hot parts or Sparks om ignition. Do not start the engine near Spied uel Never use gasoline as a cleaning agent General Recommendations Purchase gasoline in small quantities and store in clean, approved containers. A container with a capacity of 2 gallons or less with a pouring spout is recommended. Such a container is easier to handle and helps eliminate spillage during refueling, Do not use gasoline let over from the previous season, to minimize gum deposits in your fuel system and to ensure easy starting, Do not add cil to gasoline. Do not overfill the fuel tank. Leave room for the fuel to expand Fuel Type For best results, use only clean, fresh, unleaded gasoline with a pump sticker octane rating of 87 or higher. In countries using the Research method, it should be 90 octane minimum, Unleaded gasoline is recommended, as it leaves fewer combustion chamber deposits. 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 Methy! 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. 14Section 1 Safety and General Information Periodic Maintenance Bd wornine: accidental starts! } 4 Before servicing the engine or equipment, always disconnect the spark plug leads to prevent the engine trom starting accidentally. Ground the leads to prevent sparks that could cause fires. Make sure the equipment is in neutral. Maintenance Schedule These required maintenance procedures should be performed at the frequency stated in the table. They should also be included as part of any seasonal tune-up. Frequency Maintenance Required Refer to: Filtuel tank. Section S Daily or Before | Check oil ievel. Section 6 Starting Engine | Check air cleaner for dirty, loose, or damaged parts Section 4 Check air intake and cooling areas; clean as necessary’ Section 4 Every 25 Hours _ | Service precieaner element” Section 4 Replace air cleaner element Section 4 Every ‘Change engine oil. Section 6 ee Remove cooling shrouds and clean cooling areas’. Section 4 Every Change oll filter. ‘Section 6 200 Hours Check spark plug condition and gap. Section 8 ‘Annually or Every | Have bendix starter drive serviced? Section 8 500 Hours Have solenoid shit starter disassembled and cleaned? Section 8 "Perform these maintenance procedures more frequently under extremely dusty, dirty conditions. “Have a Kohler Engine Service Dealer perform this service. Storage ifthe engine will be out of service for two months or 4, Remove the spark plugs and add one tablespoon more, use the following storage procedure: of engine oil into each spark plug hole. Install plugs and ground spark plug leads-do not connect 1. Clean the exterior surfaces of the engine. the leads to the plug. Crank the engine two or three revolutions. 2. Change the oil and oil fitter while the engine is still ‘warm from operation. See “Change Oil and Oil 5. Store the engine in a clean, dry place. Filter” in Section 6, 3. The fuel system must be completely emptied, or the gasoline must be treated with a stabilizer to prevent deterioration. If you choose to use a stabilizer, follow the manufacturer's recommendations, and add the correct amount for the capacity of the fuel system. Fill the fuel tank with clean, fresh gasoline. Run the engine for 2 to 3 minutes to get stabilized fuel into the carburetor. ‘To empty the system, run the engine until the tank and system are empty. 15Section 1 Safety and General Information HP Torque ee ee PERE Figure 1-4. Typical Engine Dimensions, Torque, and Horsepower Curves OHC 16-18 HP. 16Section 1 Safety and General Information Description General Specifications’ Powor (@ 3600 RPM, comectad to SAE 1246) THI6 THIB Peak Torque (See Torque Curve) @ 2500 RPM THI6.. : THB Bore THIG THI8 Stroke THI6 THIB Displacement THI6 THIB ‘Compression Ratio THI6 THIB Dry Weight... Oil Capacity (with fier... ‘Angle of Operation - Maximum (At Full Oil Level) All Directions Blower Housing and Sheet Metal M5 Fasteners Torque .. M6 Fasteners Torque (into crankcase) M6 Fasteners Torque (into sheet baffle... Rectifier Fastener Torque ... Camshaft End Play #1 Side. #2 Side. Running Clearance Bore |.D. New Front Rear TH16 & THI8 14.9 KW (16 HP) 13.4 KW (18 HP) 35.5 N'm (26.2 ft. Ib.) 40 Nim (29.5 ft. Ib.) 73 mm (2.87 in.) 75 mm (2.95 in.) ..62 mm (2.44 in.) ...65 mm (2.56 in.) 519cc (31.7 cu. in.) '574c¢ (35.0 cu. in.) 78:1 84:1 43 kg (90 Ib.) 14L(1.5US. at) 25° 4.0 Nem (35 in. Ib.) 7.3 Nm (65in. Ib.) 4.0.N-m (365 in. tb.) 4.0.Nm (36 in. Ib.) 0.000/0.700 mm (0.000/0.0275 in.) 0.000/1.800 mm (0.000/0.0512 in.) 0.025/0.105 mm (0.0010/0.0041 in.) 92.000/32.025 mm (1.2598/1.2608 in.) 24,800/24.825 mm (0.9764/0.9774 in.) ‘Values are in Metric units. Values in parentheses are English equivalents. Lubricate threads with engine oil prior to assembly. 17Section 1 Safety and General Information Camshaft (Cont.) Bore |.D. (Cont.} Max. Wear Limit, Front . Rear Camshaft Bearing Surface 0.D. Rear Max. Wear Limit Front Rear Carburetor Carburetor Mounting Fasteners Torque Carburetor Adjustments .... Connecting Rod Cap Fastener Torque (torque in increments) 6 mm step-down ... Connecting Rod-to-Crankpin Running Clearance New... Max. Wear Limit. Connecting Rod-to-Crankpin Side Clearance .. Piston Pin End I.D. New. . Max. Wear Limit sss. Crankcase Governor Cross Shaft Bore 1.D. New... = Max. Wear Limit... Breather Cover Mounting Fasteners... Oil Drain PIUQS a snennnne Crankcase Halves Mounting Screw Torque... Crankshaft End Play wn Crankshaft Sleeve Bearing |.D. NOW nnn Max. Wear Limit Crankshaft to Sleeve Bearing Running Clearance - New 32.04 mm (1.2614 in.) 1. 24.84 mm (0.9779 in.) 1. 31.920/31.975 mm (1.2567/1.2589 in.) 24,720/24.775 mm (0.9732/0.9754 in.) 31.91 mm (1.2562 in.) 24.71 mm (0.9728 in.) 9.9 N'm (88 in. Ib.) .. Non-Adjustable Idle Fuel and Main Fuel 11.3 Nem (109 in. tb.) 0.056/0.030 mm (0.0022/0.0012 in.) 0.07 mm (0.0028 in.) .- 0.250/0.740 mm (0.0098/0.0291 in.) 17.015/17.023 mm (0,6699/0,6702 in.) . 17.04 mm (0.6708 in.) 8,025/8.050 mm (0.3159/0.3169 in.) 8.07 mm (0.3177 in.) 5.6 Nem (50 in. Ib.) 18.6 Nem (10 ft. Ib.) 24,4.N-m (216 in. Ib.) Not Adjustable 45.071/45.111 mm (1.7744/1.760 in.) 45.12 mm (1.7764 in.) 0.030/0.080 mm (0.0012/0.0036 in.)Section 1 Safety and General Information Crankshaft (Cont.) Flywhee! End Main Bearing Journal OD. = NOW ssnnnssnnnmnnne 45.021/45.044 mm (1.7725/1.7736 in.) O.D. - Max. Wear Limit... . 44.95 mm (1.7696 in.) MAK, Tap0toesnnnnnennnn 0.02 mm (0.0008 in.) Max, Out-OF- ROUND srnnnnnnnnennn 0.02 mm (0.0008 in.) PTO End Main Bearing Journal OD. = NOW srnnesnnnemnnee 45.021/45.041 mm (1.6107/1.6116 in.) (O.D. - Max. Wear Limit 44.95 mm (1.7696 in.) Max. Taper (0.02 mm (0.0008 in.) Max. Out-of-Round (0.02 mm (0.0008 in.) Connecting Rod Journal ‘OD. - New oe 31.948/31.966 mm (1.2578/1 2585 in.) ‘OD. - Max. Wear Limit. snnsnnnneenns 31.93 mn (1.2571 in.) Max. Taper: cee (0.02 mm (0.0008 in.) Max. Outof-Round. sssonnnnes 0,02 mm (0.0008 in.) Crankshaft TLR. PTO End, Crank in Engine ssosnmennes 0,015 mm (0.0006 in.) Entire Crank, in V-Blocks 0.010 mm (0.0004 in.) Cylinder Bore Cylinder Bore I.D. New THI6 .oconnnnnnnnnnnnnn svonnnnnesnnnes 73,006/73.081 mm (2.8742/2.8752 in.) THIB Seem see 75,025/75,050 mm (2.9537/2.9547 in.) Max. Wear Limit THIE.... Cees e «- 73.07 mm (2.8767 in.) THIB... See —— 75.09 mm (2.9563 in.) Max, QULOFROUNT wo snnsnnnnnnne : 0.13 mm (0.005 in.) Max, Taper —— 0.13 mm (0.005 in.) Electric Starter Starter Mounting Fastener Torque 7.9.Nm (70in. tb.) Timing Belt Belt Tensioner Mounting Screw Torque — 7.3 Nem (65 in. Ib.) Belt Tension Torque . 3.4/4.5 N-m (30/40 in. Ib.) Fan/Flywheel Fan Fastener Torque a . 9.9 Nem (88 in. Ib.) Flywheel Retaining Screw Torque ....nn1nnnnsnnnnnmnnrnnnne 66.4 Nem (49 ft. Ib.) Governor Governor Gross Shaft to Crankease Running Clearance — sssnnsnmnsennenes 0,01310,075 mm (0.0008/0,0030 in.) Governor Cross Shaft ©.0, New... _ .- 7.975/8.012 mm (0.3140/0.3154 in.) Max. Wea Limit sone 7.96 mm (0.8134 in.) 19Section 1 Safety and General Information Governor (Cont.) Governor Bushing to Camshaft Running Clearance .. 0.045/0.160 mm (0.0018/0.0063 in.) Governor Bushing 1.0. New Max. Wear Limit «. $2,020/32.080 mm (1.2606/1.2630 in.) 32.09 mm (1.2634 in.) Ignition Spark Plug Type (Champion® or Equivalent) : Ro12vC Spark Plug Gap eee 0.76 mm (0.030 in.) ‘Spark Plug Torque . 24.4/29.8 Nem (18/22 ft. lb.) Ignition Module Air Gap seven vee 0.2010,80 mm (0,008/0.012 in.) Ignition Module Fastener Torque sevens 4,016.2 N-m (35/58 in. Ib.) Muffler Mufller Retaining Nuts Torque... 24.4 Nem (216 in. tb.) Oil Filter Oil Filer Torque nen 5.6/9.0 N'm (50/80 in. tb.) il Filter Nipple Torque 40.7 Nem (30 ft. Ib.) Oil Sentry™ Pressure Switch. moo 3.4 Nem (30 in. Ib.) Piston, Piston Rings, and Piston Pin Piston Pin Bore to Piston Pin (Select Fit). 0,006/0.016 mm (0.0002.0.0007 in.) Piston Pin Bore |.D. New Max. Wear Limit 17.006/17.012 mm (0.6695/0.6698 in.) 17.025 mm (0.6703 in.) Piston Pin 0.0. New es 16.996/17.000 mm (0.6691/0.6693 in.) Max. Wear Limit 16.995 mm (0.6691 in.) Top Compression Ring-to-Groove Side Clearance THIE ee 0.040/0.085 mm (0.0016/0.0033 in.) THe eee (0.040/0.085 mm (0.0016/0.0033 in.) Middle Compression Ring-to-Groove Side Clearance THI ne ve (0.030/0.080 mm (0.0012/0.0031 in.) THIB ns vn (0.030/0.076 mm (0.0012/0.0030 in.) Oil Control Ring-to-Groove Side Clearance THI6 . . 0,046/0,201 mm (0.0018/0.0079 in.) TH18 (min.) 0.070 mm (0.0028 in.) ‘Top Compression Ring End Gap ae 1: 0.180/0.380 mm (0.007/1/0.0150 in.) 1.10Section 1 Safety and General Information Piston, Piston Rings, and Piston Pin (Cont.) Middle Compression Ring End Gap THI6.. es THB Piston Thrust Face 0.0? THI6 NOW rr Max. Wear Limit... THs New. Max. Wear Limit Piston Thrust Face-to-Cylinder Bore? Running Clearance THI6 THB ‘Speed Control ‘Speed Control Bracket Assembly Fastener Torque Stator Stator Mounting Screw Torque Throttle/Choke Controls Governor Control Lever Fastener Torque ... Valve Cover Valve Cover Fastener Torque. Valves Intake Valve Stem-to-Valve Guide Running Clearance Exhaust Valve Stem-to-Valve Guide Running Clearance ns Intake Valve Guide 1.0. ‘New = Max. Wear Limit Exhaust Valve Guide Neweeeee Max. Wear Limit Valve Guide Reamer Size Standard 0.25 mm O.S. Intake Valve Minimum Lift Exhaust Valve Minimum Lift Nominal Valve Seat Angle -»- 0.4180/0.440 mm (0.0071/0.0173 in.) (0.180/0.450 mm (0.0071/0.0177 in.) 72,986/72.984 mm (2.8727/2.8734in.) 72,839 mm (2.8677 in.) 74.986/74.984 mm (2.9514/2.9521 in.) 74.839 mm (2.9464 in.) 0.022/0.065 mm (0.0009/0.0026 in.) 0.041/0.084 mm (0.0016/0.0033 in.) 9.9 Nm (88 in. Ib.) 4.0 Nim (35 in. b.) . 9.9 Nem (88 in. Ib.) 5.6 N'm (50 in. Ib.) 0.038/0.076 mm (0.0015/0.0030 in.) 0.050/0.088 mm (0.0020/0.0035 in.) .- €.036/6.058 mm (0.2377/0.2385 in.) sn 6.13 mm (0.2413 in.) 6.038/6.058 mm (0.2377/0.2385 in.) 6.19 mm (0.2437 in.) 6.048 mm (0.2381 in.) 6.298 mm (0.2480 in.) 7.50 mm (0.295 in.) 7.50 mm (0.295 in.) 45° *Measure 6 mm (0.236 in.) above the bottom of the piston skirt at right angles to the piston pinSection 1 Safety and General Information Valves (Cont.) Valve Lash MaKe oo. srnnnnnnnnnnnnnnnnnnnnnns sexes 0.013/0,064 mm (0.0005/0.0025 in.) EXHAUSE snr ssoeeeseneeeesre 0,07610.127 mm (0.0030/0.0050 in.) General Torque Values Metric Fastener Torque Recommendations for Standard Applications Tightening Torque: N-m (in. Ib.) + or - 10% Property Class Nonertical = Fasteners me ‘Aluminum m4 1.2 (11) 4.7 (15) 2.9 (26) 4.1 (36) 5.0 (44) 2.0 (18) MS 25 (22) 32 (28) 58(5t) —8.1(72) «9.7 (66) 4.0 (35) M6 4.3 (38) 5.7 (50) 9.9 (88) 14,0 (124) 16.5 (146) 6.8 (60) Ms 105 (93) 436 (120) 244 (216) _33:9(300) _40.7 (360) 17.0 (150) Tightening Torque: N-m (ft. tb.) + or - 10% Property Class Nonertical Fasteners ‘Aluminum mio 217(16) 27.1 (20) 47.5(35) —-66.4(49) 81.4 (60) 33.9 (25) M12 36.6 (27) 47.5 (35) 82.7 (61) 116.6 (86) 139.7 (103) 61.0 (45) M14 58.3 (43) 76.4 (55) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70) Torque Conversions Nem = in. Ib. x0.113 Nem =f b,x 1.356 in. Ib. = Nem x 8.85 fi. Ib. = Nem x 0.737Section 1 Safety and General Information Tightening Torque: N-m (in. Ib.) + or - 20% Bolts, Screws, Nuts and Fasteners, [Assembled Into Cast Iron or Steel Grade 2 or 5 QO © & a crate? cvaies conde O@ ‘Size 3.32 2.3 (20) 2.8.25) 10-24 38 (82) 45 (40) oa 35,62) 45,40) 38032) 114-20 7.9(70) 13.0 (115) 18.7 (165) 2) 114-28 96 (5) 15.8(140) 22.6 (200) joan 516-18 47.0 (180) 28.3 (250) 39.6 (350) (70) 516-24 18.7 (165) 30.5 (270) - > 318-16 29.4 (260) - ~ eee 318-24 33.9 (300) . - nnn Tightening Torque: Nm (ft. Ib.) + or - 20% nse 40.7 (30) 47.5 (35) 67.8 (50) 54.2 (40) 81.4 (60) 47.5 (35) 74.6 (55) 108.5 (80) 61.0 (45) 101.7 (75) 142.4 (105) 67.8 (50) 108.5 (60) 155.9 (115) 94.9 (70) 442.4 (105) 223.7 (165) 916-12 101.7 (75) 169.5 (125) 237.3 (175) 916-18 135.6 (100) 223.7 (165) 311.9 (230) 58-11 149.2 (110) 244.1 (180) 352.6 (260) 518-18 189.8 (140) 311.9 (230) 447.5 (330) 314-10 199.3 (150) 332.2 (245) 474.6 (350) 314-16 271.2 (200) 440.7 (325) 637.3 (470) 1.43TH16 & TH18 Section 2 Special Tools ‘These quality tools are designed to help you perform specific disassembly, repair, and reassembly procedures. By Using tools designed for the job, you can service engines easier, faster, and safer! In addition, youll increase your service capabilities and customer satisfaction by decreasing engine downtime. Flywheel Strap Wrench Flywheel Puller Kit Water Manometer Cylinder Leakdown Tester Ignition System Tester ‘Camshaft Timing Tool Set Starter Snap Ring Kit a Valve Blocking Tools and Engine Stand ... Contact your Kohler Distributor for price and availabilty, Ignition System Tester Use Kohler Part No, 24 455 02 to test the CD ignition modules on the OHC engines. Cylinder Leakdown Tester Kohler Part No. 25 761 05 Cylinder Leakdown Tester is a valuable alternate to a compression test. By pressurizing the combustion chamber from an external air source, this tool can determine if valves or rings are leaking. Instructions for using this tester are found on page 3.4 ofthis manual. Special Tools You Can Make Flywheel Holding Tool Flywheel removal and reinstallation becomes a “snap” using a handy holding tool you can make out of a piece of an old “junk” fiywheel ring gear as shown in Figure 2-1. Using an abrasive cut-off wheel, cut out a six tooth segment of the ring gear as shown. Grind off any burrs or sharp edges. The segment can be used in, place of a strap wrench. Invert the segment and place it between the ignition bosses on crankcase so that the tool teeth engage the ring gear teeth on the flywheel ‘The bosses will "lock" the tool and flywheel in position for loosening, tightening or removing with a puller. NU-10357 NU-3226 25 761 02 25 761 05 24 455 02 2876101 2576118 28 761 02 Figure 2-1. Flywheel Holding Tool. 24Special Tools RTV Silicone Sealant ATV silicone sealant is used as a gasket on the crankcase halves, breather cover gasket,”* and oil filter adapter. The chart below lists some of the approved sealants. RTV Sealants Vendor Vendor No. and Description RTV-102White — RTV-109 Gray GE RTV-103 Black RTV-154 Gray RTV-106Red —_RTV-156 Red RTV-108Clear__RTV-1473 Black 598 Black '598 Black” Lootite* | 594 White '5900 Black 595 Clear 6 Blue 6M Blue Permatex | 68 Blue 668 Clear 6C Blue 66C Clear *NOTE: Loctite? No, 598 is available in a handy 10 ce size syringe type dispenser (with 2 disposable tips) under Kohler Part No. 25 597 04. Figure 2-2. Loctite® No. 598 Syringe Dispenser. NOTE: “NOTE: Always use fresh sealant. Using outdated sealant can result in leakage. Generally, the shelt life of an unopened dispenser is about 1 year while that of a used one is not more than 6 months. ‘Two styles of breather cover gaskets have been used. One style has a sealant bead already on the surface and does not require any additional RTV. 22TH16 & TH18 Section 3 Troubleshooting 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 common causes of engine troubles are listed below. Use these to locate the causing factors. Engine Cranks But Will Not Start Empty fuel tank. Fuel shut-off valve closed. Dirt or water in the fuel system. Clogged fuel line. Spark plug lead disconnected. Key switch or kill switch in “oft” position. Faulty spark plugs. Faulty ignition module. Carburetor solenoid matfunction, Engine Starts But Does Not Keep Running 4. Restricted fuel tank cap vent. 2. Dirt or water in the fuel system, 3. Faulty choke or throttle controls. 4, Loose wires or connections that short the kill terminal of ignition module to ground. 5. Faulty carburetor. Engine Starts Hard PTO drive is engaged. Dirt or water in the fuel system. Clogged tuel ine. Loose or faulty wires or connections. Faulty choke or throttle controls. Faulty spark plugs. Low compression. Weak spark. Engine Will Not Crank. PTO drive is engaged Battery is discharged. Safely interlock switch is engaged. Loose or faulty wires or connections. Faulty key switch or ignition switch: Faulty electric starter or solenoid. Seized internal engine components. Engine Runs But Misses Dirt or water in the fuel system, ‘Spark plug lead disconnected. Loose wires or connections. Engine overheated, Faulty ignition module. Faulty spark plugs. Engine Will Not Idle 1. Restricted fuel tank cap vent. 2. Dirt or water in the fuel system. 3. Faulty spark plugs. 4. Idle speed adjusting screw improperly set 5. Low compression 6. Stale fuel and/or gum in carburetor. Engine Overheats 4. Air intake or grass screen, cooling fins, or cooling shrouds clogged Excessive engine load Low crankcase oil level. High crankcase oil level Faulty carburetor. geen Engine Knocks 4. Excessive engine load. 2. Low crankcase oil level. 3. Old or improper fuel. 4, Internal wear or damage. aSection 3 Troubleshooting Engine Loses Power Low crankcase oil level High crankcase cil level. Dirty air cleaner element, Dirt or water in the fuel system. Excessive engine load. Engine overheated Faulty spark plugs. Low compression, Exhaust restriction. Engine Uses Excessive Amount Of Oil Incorrect oil viscosity/type, Clogged or improperly assembled breather. Worn or broken piston rings. Worn cylinder bore. Worn valve stems or valve guides. Crankcase overtilled, Oil Leaks From Oil Seals, Gaskets 1. Crankcase breather is clogged or inoperative. 2. Loose or improperly torqued fasteners, 3. Piston blowby or leaky valves. 4. Restricted exhaust. External Engine Inspection Before cleaning or disassembling the engine, make a thorough inspection ofits external appearance and condition. This inspection can give clues to what might be found inside the engine (and the cause) when it is disassembled. + Check for buildup of dirt and debris on the crankcase, cooling fins, grass screen and other external surfaces. Dirt or debris on these areas are causes of overheating, + Check for obvious fuel and oil leaks, and damaged components. Excessive oil leakage can indicate a clogged or improperly assembled breather, worn or damaged seals and gaskets, or loose or improperly torqued fasteners. + Check the air cleaner cover and base for damage or indications of improper fit and seal. + Check the air cleaner element. Look for holes, tears, cracked or damaged sealing surfaces, or other damage that could allow unfiltered air into the engine. Also note if the element is dirty or clogged. These could indicate that the engine has been underserviced + Check the carburetor throat for dit. Dirt in the throat is further indication that the air cleaner is not functioning property. + Check the oil level. Note if the oll level is within the operating range on the dipstick, or it itis low or overfilled. + Check the condition of the oil, Drain the oil into a container - the oil should flow freely. Check for metal chips and other foreign particles. Sludge is a natural by-product of combustion; a ‘small accumulation is normal. Excessive sludge formation could indicate overrich carburetion, weak ignition, overextended cil change interval or wrong weight or type of oil was used, to name a few. NOTE: tis good practice to drain oil at a location away from the workbench. Be sure to allow ample time for complete drainage. Cleaning the Engine Aiter inspecting the external condition ofthe engine, clean the engine thoroughly before disassembling it. {io clean individual components as the engine is disassembled. Only clean parts can be accurately inspected and gauged for wear or damage. There are many commercially available cleaners that wil quickly remove grease, oi, and grime from engine parts When such a cleaner is used, folow the ‘manufactures instructions and safely precautions carefully Make sure all traces of the cleaner are removed before the engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil 32Section 3 Troubleshooting Basic Engine Tests Crankcase Vacuum Test A partial vacuum should be present in the crankcase ‘when the engine is operating at normal temperatures. Pressure in the crankcase (normally caused by a clogged or improperly assembled breather) can cause oil to be forced out at cil seals, gaskets, or other available spots. Crankcase vacuum is best measured with a water manometer. Kohler Part No. 25 761 02 is recommended. Complete instructions are provided in kit Test the crankcase vacuum with manometer as follows: 1. Insert the stopperihose into the oil fill hole. Leave the other tube of manometer open to atmosphere. Make sure the shut-off clamp is closed. Start the engine and run at no-load high idle speed (3200 to 3750 RPM). Open the clamp and note the water level in the tube. The level in the engine side should be a minimum, of 30 cm (12 in.) above the level in the open side. Ifthe level in the engine side is the same as the ‘open side (no vacuum), or the level in the engine side is lower than the level in the open side (pressure), check for the conditions in the table below. Close the shut-off clamp before stopping the engine. No Crankcase Vacuum/Pressure in Crankcase Possible Cause Solution 1. Crankcase breather clogged or inoperative. 2. Seals andlor gaskets leaking. Loose or improperly torqued fasteners. 3. Piston blowby or leaky valves. (Confirm by inspecting components. 4. Restricted exhaust. Disassemble breather, clean parts thoroughly, reassemble, and recheck pressure, Replace all worn or damaged seals and gaskets. Make sure all fasteners are tightened securely. Use appropriate torque values and sequences when necessary. Replace piston and/or rings. Recondition/replace valves. Recondition valve guides. See Section 10. Repairireplace restricted muffler/exhaust system. Compression Test ‘Some of these engines are equipped with an automatic compression release (ACR) mechanism. Because of the ‘ACR mechanism, itis difficult to obtain an accurate compression reading. As an alternate, use the leakdown test described on the next page. 33Section 3 Troubleshooting Cylinder Leakdown Test A cylinder leakdown test can be a valuable alternative 10 a compression test. By pressurizing the combustion chamber from an external air source, you can determine if the valves or rings are leaking, and how badly, Kohler Part No. 25 761 05 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 Leakdown Test Instructions 1, Run engine for 3-5 minutes to warm it up. 2. Remove spark plug(s) and air filter from engine. 8. Rotate crankshaft until piston (of cylinder being tested) is at top dead center of compression stroke. You will need to hold the engine in this position while testing. The holding tool supplied with the tester can be used if the PTO end of the crankshaft is accessible. Slide the holding tool conto the crankshaft and adjust the set screw to fit inthe key slot. Install a 3/8" breaker bar into the square hole of the holding tool, so itis perpendicular to both the holding tool and ‘crankshaft PTO. If the flywheel end is more accessible, you can use a breaker bar and socket on the flywheel nut’screw to hold it in position, You may need an assistant to hold the breaker bar during testing. f the engine is mounted in a piece of equipment, you may be able to hold it by Clamping or wedging a driven component. Just be certain that the engine cannot rotate off of TDC in either direction. Install the adapter into the spark plug hole, but do ‘not attach it to the tester at this time. Connect an air source of at least 50 psi to the tester. ‘Tum the regulator knob in the increase (clockwise) direction until the gauge needle is in the yellow “set” area at the low end of the scale. Connect tester quick-disconnect to the adapter hose while firmly holding the engine at TDC. Note the gauge reading and listen for escaping air at the carburetor intake, exhaust outlet, and crankcase breather. Check your test results against the table below: Leakdown Test Results Air escaping from crankcase breather Air escaping from exhaust system... Air escaping from carburetor Gauge reading below 25% leakage Gauge reading 25% - 50% leakage Gauge reading above 50% leakage Defective rings or worn cylinder walls. Defective exhaust valve. Defective intake valve. Piston rings and cylinder in good condition. Engine is still usable, but there is some wear present. Customer should start planning for ‘overhaul or replacement. Rings and/or cylinder have considerable wear. Engine should be reconditioned or replaced. a4TH16 & TH18 Section 4 Air Cleaner and Air Intake System Air Cleaners General ‘These engines are equipped with a replaceable, high- density paper air cleaner element. Most are also ‘equipped with an oiled-foam precleaner which surrounds the paper element. ‘Two different types are used. The standard type air cleaner is shown in Figure 4-1, while the top tank type air cleaner is shown in Figure 4-2. Internal components vary, however the service recommendations are the same. Figure 4-1, Standard Figure 4-2. Top Tank Air Cleaner. Service Check the air cleaner daily or before starting the engine. Check for and correct heavy buildup of dirt and debris along with loose or damaged components. NOTE: Operating the engine with loose or damaged air cleaner components could allow unfitered air into the engine causing premature wear and failure, Precleaner Service I so equipped, wash and reoil the precleaner every 25 hours of operation (more often under extremely dusty or dirty conditions). To service the precleaner perform the following steps: 1. Loosen the cover retaining knob and remove the cover. 2. Remove the foam precleaner from the paper air cleaner element, 44Section 4 Air Cleaner and Air Intake System 3, Wash the precleaner in warm water with detergent. Rinse the precieaner thoroughly until all races of detergent are eliminated. Squeeze out excess water (do not wring). Allow the precleaner to air dry Saturate the precleaner with new engine cil ‘Squeeze out all excess oil Reinstall the precleaner over the paper air cleaner element, Reinstall the air cleaner cover. Secure cover with the cover retaining knob. Figure 4-3. Top Tank Air Cleaner with Cover Removed. Paper Element Service Every 100 hours of operation (more often under ‘extremely dusty or dirty conditions), replace the paper element. Follow these steps’ 1. Loosen the cover retaining knob and remove the cover. 2, Remove the wing nuts), element cover, and air cleaner element 3. Remove the precleaner (if so equipped) from the paper element. Service the precleaner. 4, Donot 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, 5. Reinstall the paper element, precleaner, element cover, and wing nuts). 6. Reinstall the air cleaner cover and secure cover with the retaining knob. Figure 4-4. Removing Element on Standard Type. 42Section 4 Air Cleaner and Air Intake System >, — Knob Element __¢ Cover Element Cover Base Assembly — <> Base Gasket Figure 4-5. Standard Air Cleaner System Figure 4-6. Top Tank Air Cleaner System ‘Components. Components. 43Section 4 Air Cleaner and Air Intake System 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, Grommet, and Seal ~ Make sure element cover is not bent or damaged. Make sure the wing nut, grommet, and seals are in place to ensure the element is sealed against leakage. Be sure the grommet aligns with the hole in the base. If the element cover is installed backward, the hole in the base will not be sealed, Air Cleaner Base ~ Make sure the base is secured tightly to carburetor elbow and not cracked or damaged NOTE: Damaged, worn, or loose air cleaner components can allow unfiltered air into the engine causing premature wear and failure. Tighten or replace all loose or damaged components Complete Disassembly and Reassembly Ifthe base plate has to be removed, proceed as follows: 1. Remove air cleaner components from the base as described under “Paper Element Service” (see page 4.2) 2. Remove the hex. flange screws securing the bracket (top tank version) and base (Figure 4-7). 3. Remove the base and gasket 4, Reverse procedure to reassemble components. Tighten screws to 9.9 N'm (88 in, Ib.) torque. Figure 4-7. Removing Base on Standard Type Air Cleaner. Air Intake/Cooling System To ensure proper cooling, make sure the grass screen, cooling fins, and other external surfaces of the engine are kept clean at al times. Every 100 hours of operation (more often under extremely dusty or dirty conditions), remove the blower housing and other cooling shrouds.” Clean the cooling fins and external surfaces as necessary. Make sure the cooling shrouds are reinstalled. *Cleanout kit 24 755 90 can be used for inspection and cleanout of the cooling fins without removing the blower housing or shrouds. NOTE: Operating the engine with a blocked grass ‘screen, dirty or plugged cooling fins, and/or cooling shrouds removed, will cause engine damage due to overheating, 44TH16 & TH18 Section 5 Fuel System and Governor Description Awnanine: explosive Fuel! Gasoline is extremely flammable and its vapors can explode it ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, nay from sparks or flames. Do not fil the fuel tank while the engine is hot or running, since spilled fuel could ignite iit comes in contact with hot parts or sparks from ignition. Do not start the engine near piled fuel. Never use gasoline as a cleaning agent. Fuel System Components ‘The typical fuel system and related components include the following. + Fuel Tank + Fuel Lines + In-Line Fuel Filter + Fuel Pump + Carburetor Operation The fuel from the tank is moved through the in-line filter and fuel lines by the fuel pump. Fuel then enters ‘the carburetor float bow! and is moved into the carburetor body. There, the fuel is mixed with air. This fuel-air mixture is then burned in the engine combustion chambers. Fuel Recommendations General Recommendations Purchase gasoline in small quantities and store in clean, approved containers. A container with a capacity of 2 gallons or less with a pouring spout is, recommended. Such a container is easier to handle and helps eliminate spillage during refueling. + Donot use gasoline left over from the previous season to minimize gum deposits in your fuel system and to ensure easy starting, + Donot add oil to the gasoline. + Donot overfill the fuel tank. Leave room for the fuel to expand. Fuel Type For best results, use only clean, fresh, unleaded gasoline with a pump sticker octane rating of 87 or higher. In countries using the Research tuel rating ‘method, it should be 90 octane minimum. Unleaded gasoline is recommended, as it leaves less combustion chamber deposits. 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. Other gasoline/ether blends are not approved. Fuel Filter Most engines are equipped with an inne filter. Periodically inspect the filter and replace when dirty, with a genuine Kohler fer. 5ASection 5 Fuel System and Governor Fuel System Tests When the engine starts hard, or turns over but wll not star, itis possible thatthe problem is in the fuel system. To find out ifthe fuel system is causing the problem, perform the following tests. Troubleshooting — Fuel System Related Causes Test Conclusion Check the following ‘a. Make sure the fuel tank contains clean, fresh, proper fuel. b. Make sure the vent in fuel tank cap is open. c._ Make sure the fuel valve is open, ‘a. Remove the fuel line from the inlet fiting of carburetor. b. Crank the engine several times and observe flow. 12. Check for fuel in the combustion chamber. 2. If there is fuel at the tip of the spark plug, fuel is a. Disconnect and ground spark plug leads. reaching the combustion chamber. b. Close the choke on the carburetor. ¢. Crank the engine several times. If there is no fuel at the tip of the spark plug, d. Remove the spark plug and check for fuel at ccheck for fuel flow from the fuel tank (Test 3) the tip, 3. Check for fuel flow from the tank to the fuel pump. | 3, If fuel does flow from the line, check for faulty fuel ‘a. Remove the fuel line from the inlet fiting of pump (Test 4) fuel pump, b. Hold the line below the bottom of the tank. If fuel does not flow from the line, check for Open the shut-off valve (it so equipped) and clogged fuel tank vent, fuel pick-up screen, in-line observe flow. filter, shut-off valve, and fuel lines. /4, Check the operation of fuel pump. 4. If fuel does flow from the line, check for faulty carburetor. (Refer to the “Carburetor” portions ofthis section.) I fuel does nat flow from the line, check for clogged fuel line. Ifthe fuel line is unobstructed, the fuel pump is faulty and must be replaced. 52Section 5 Fuel System and Governor Fuel Pump General Most engines are equipped with a mechanical fuel pump. The pumping action is created by a lobe on the #1 side camshaft. The pumping action causes the diaphragm on the inside of the pump to pull fuel in on its downward stroke and to push it into the carburetor nits upward stroke. Two check valves prevent fuel from going backward through the pump. Performance Fuel pump outlet pressure should not exceed 18.79 kPa (2 psi) to avoid overriding the float system in the carburetor. Replacing the Fuel Pump Replacement valve cover/tuel pumps are available through your source of supply. To replace the valve coverfuel pump assembly, follow these steps: 1. Disconnect the fuel lines from the inlet and outlet fittings. Figure 5-1. Removing #1 Side Valve Cover/Fuel Pump Assembly. 2. Remove the four hex. flange screws and valve coverifuel pump. 3. Install a new valve covertuel pump using the hex. flange screws. 4, Tighten the hex. ange screws to 5.6 N-m (50 in. tb.) 5. Connect the fuel lines to the inlet and outlet fittings. Carburetor General Engines in this series are equipped with fixed jet carburetors. Some applications utilize a fuel shut-off solenoid which is installed in place of the fuel bow! retaining screw. All carburetors feature the selt- relieving choke components shown in the exploded view on page 5.9. These carburetors include three ‘main circuits which function as follows. Float Circuit: Fuel level in the bow! is maintained by the float and fuel inlet needle. The buoyant force of the float stops fuel low when the engine is at rest. When fuel is being consumed, the float will drop and fuel pressure will push the inlet needle away trom the seat, allowing more fue! to enter the bowl. When demand eases, the buoyant force of the float will again ‘overcome the fuel pressure and stop the flow. Slow Circuit (See Figure 5-2): Atlow speeds the engines operates only on the slow circuit. As a metered amount of air is drawn through the slow air bleed jet, fuel is drawn through the main jet and further metered through the slow jet. Air and fuel are mixed in the body of the slow jet and exit to the transfer port From the transfer port this air fuel mixture is delivered to the idle progression chamber. From the idle progression chamber the air fuel mixture is metered through the idle port passage. Atlow idle when the vacuum signal is weak, the air fuel mixture is Controlled by the setting of the non-accessible idle adjust screw. This mixture is then mixed with the main body of air and delivered to the engine. As the throttle plate opening increases, greater amounts of air fuel mixture are drawn in through the fixed and metered idle progression holes. As the throttle plate opens further the vacuum signal becomes great enough so the main circuit begins to work. 53Section 5 Fuel System and Governor Slow Circuit 1. Slow Air Bloed Jet 2. Siow Jet 3. Transfer Port 4, Idle Progression Chamber 5. Idle Limiter Jet 6. Idle Port Passage 7. Idle Port 8. Idle Progression Holes 9. Bow! Vent Figure 5-2. Slow Circuit. Main Circuit (Figure 5-3): At high loads, the engine operates mostly on the main circuit. As a metered amount of air is drawn through the main air bleed jet, fuel is drawn through the main jet. The air and fuel are ‘mixed in the main nozzle and then enter the main body of air flow, where further mixing of the fuel and air takes place. This mixture is then delivered to the combustion chamber. The carburetor has a fixed main circuit. There is no adjustment feature present. 10. Main Circuit Choke Plate Throttle Plate Main Nozzle Emulsion Tube (Part of Main Nozzle) Main Jet Main Air Bleed Jet Inlet Needle Pin Float Fuel Inlet Figure 5-3. Main Circuit. 5aSection 5 Fuel System and Governor Troubleshooting - Carburetor Related Causes Condition Possible Cause/Probable Remedy Engine starts hard, runs roughly, or stalls at idle speed. 1. Low idle speed improperly adjusted. Adjust the low idle speed screw. 2. Engine runs rich (Indicated by black, sooty exhaust smoke, misfiring, loss of speed and power, ‘governor hunting, or excessive throttle opening). Clogged air cleaner. Clean or replace. 'b. Choke partially closed during operation. Check the choke lever! linkage to ensure choke is operating properly. c. Float level too high. Separate fuel bow! from carburetor body. Free (if stuck), or replace float. 4. Dirt under the fuel inlet needle. Remove needle; clean needle and seat and blow with compressed air. . Bowl vent or air bleeds plugged. Clean vent, ports, and air bleeds. Blow out all passages with compressed air. {. Leaky, cracked, or damaged float. Submerge float to check for leaks. ‘3. Engine runs lean (indicated by misfiring, loss of speed and power, governor hunting, or excessive throttle opening). Float level too low. Separate fuel bow/ from carburetor body. Free (it stuck) or replace float. b. Idle holes plugged; di in fuel delivery channels. Clean main fuel jt and all passages; blow out with compressed air. ‘4. Fuel leaks from carburetor. 4a. Float stuck. See Remedy 2c. b. Dirt under fuel inlet needle. See Remedy 2d. c. Bowl vents plugged. Blow out with compressed air. d._ Carburetor bowi gasket leaks. Replace gasket. Troubleshooting Checklist When the engine starts hard, runs roughly, or stalls at low idle speed, check the following areas before + Make sure the air cleaner base and carburetor are securely fastened to the engine using gaskets in good condition. adjusting or disassembling the carburetor. ‘+ Make sure the fuel tank is filled with clean, fresh gasoline. + Make sure the air cleaner element is clean and all air cleaner components are fastened securely. ‘+ Make sure the ignition system, governor system, ‘+ Make sure the fuel tank cap vent is not blocked and that it is operating propery. ‘+ Make sure fuel is reaching the carburetor. This includes checking the fuel shut-off vaive, fuel tank. fiter screen, in-line fue! fiter, fuel lines, and fuel pump for restrictions or faulty components as necessary, exhaust system, and throttle and choke controls, are operating properly. Ifthe engine is still hard to start, runs roughly, or stalls at low idle speed, it may be necessary to service the carburetor. 55Section 5 Fuel System and Governor Fuel Shut-off Solenoid ‘Some carburetors are equipped with an optional fuel shut-off solenoid. The solenoid is installed in place of the bow! retaining screw. The solenoid has a spring-loaded pin that retracts when 12 volt current is applied to the lead. The pin blocks the main fuel jet and prevents fuel from entering the carburetor when it is extended, Below is a simple test made with the engine off that can determine if the solenoid is functioning propery: 1. Shut off the fuel and remove the solenoid from the carburetor. When the solenoid is loosened and removed, gas will leak out of the carburetor. Have a container ready to catch the fuel, 2. Attach a wire between the solenoid ground lead terminal and a battery ground with alligator clips. Acaution Do this test away from any fuelvapors to prevent an accident. 3. Insert a bare 1/4" male spade terminal into the terminal end of the power lead. Touch the ‘exposed terminal to the positive (+) post of the battery. 4, Ifpin retracts, the solenoid is good Adjustments General ‘The carburetor is designed to deliver the correct fuel to-air mixture to the engine under all operating conditions. Fuel mixture settings are set at the factory and are not adjustable NOTE: Carburetor speed adjustment should be made only after the engine has warmed up. Figure 5-4. Fuel Shut-off Solenoid Equipped Carburetor. Low Idle Speed Adjusting Screw To adjust the carburetor idle speed, see Figure 5-5 and follow these steps: 1. Start the engine and run at haif throttle for 5 to 10 minutes to warm up. The engine must be warm before making final settings. Check that the throttle and choke plates can fully open. NOTE: The carburetor has a selt-relieving choke. Choke plate and shaft assembly is spring loaded. Check to make sure plate moves freely and is not binding and affecting idle fuel delivery. 56SectionS Fuel System and Governor Low Idle [Speed Adjusting Screw Figure 5-5. Carburetor Adjustment 2, Place the throttle control into the “idle” or “slow” Position. Tum the low idle speed adjusting screw in or out to obtain a low idle speed of 1200 RPM (#75 RPM). Check the speed using a tachometer. “NOTE: The actual low idle speed depends on the application. Refer to the equipment manufacturer's recommendations. The low idle speed for basic engines is 1200 RPM (75 RPM). Float Replacement If symptoms described in the carburetor troubleshooting qude indicate float level problems, remove the carburetor from the engine to check andi or replace the float. Use Float Kitto replace float, pin and inlet needle or valve Float Kit Contains: 4, Disconnect lead wires from fuel shut-off solenoid ‘equipped carburetor. 5. Slide the carburetor off the retaining studs. Remove the fuel bow! retaining nut or fuel shut-off solenoid and drain fuel from the bow! into a safe container. Remove the bow! from the carburetor body. 6. Turn the carburetor body upside down and check level ofthe float as shown in Figure 5-6. With the float needle valve fully seated, 16.5 mm (.65") should be measured from the body to float as indicated. Don't attempt to adjust by bending the tab ~ replace float with kit i level is wrong. Turn Carburetor ne Upside Down aty. Description 1 Float 1 Valve, float (inlet needle) 1 Pin, float 1 Gasket, carburetor 1 Gasket, air cleaner base 1. Remove the air cleaner and air intake components from the carburetor as described in Section 4, 2. Disconnect the fuel inlet line from the carburetor. 3. Disconnect governor throttle linkage from the carburetor. Figure 5-6. Proper Float Level 7. Pull the float hinge pin and remove the float with float needle valve attached to inspect these parts and needle seat. If dirty, blow out with ‘compressed air. Replace float components as needed with kit 8. Use new bow! gaskets, reinstall bow, tighten bow retaining screw or solenoid if used to 5.1/6.2 N-m (45/55 in. Ib.) 9. Reinstall carburetor on engine, reconnect fuel line, contro! linkages and air intake components. Retest operation, 87Section 5 Fuel System and Governor Disassembly Disassemble carburetor as follows after removal from engine. See Figure 5-7. 1. Remove the fuel bow! retaining screw or solenoid assembly then remove bowl and bowl gasket. 2. Pullthe float hinge pin and remove the float with inlet needle attached, 3. Remove the vent plug from the column on. solenoid equipped carburetors. 4, Remove the setscrews holding the throttle plate to the throttle shatt and pull the throttle shaft from carburetor body. 5. Remove the setscrews securing the choke plate to the choke shaft assembly and pull the choke shatt assembly out of the carburetor body. Disassemble selt-relieving parts from shaft as needed. 6. Remove the three screws holding the passage cover to the body and remove the cover gasket. 7. Remove the slow speed adjusting needle and. spring. Except for the slow jet nozzle, main jet, and emulsion tubes, which are considered non-serviceable, the carburetor is now completely disassembled and ready for thorough inspection and cleaning, 83 -10 Cover Retaining Screw Passage Cover Cover Gasket Carburetor Body Self-Relieving Choke Choke Plate Setscrew (Plates - 4) Bowl Retaining Screw Gasket ‘Shut-Off Solenoid Assembly |. Bow! Retaining Screw |. Fuel Bowl Float Kit Fuel Bow! Gasket Main Jet Throttle Shatt/Lever Throttle Plate Spring, Idle Speed Screw, Idle Speed Adjusting Figure 5-7. Carburetor - Exploded View. 58Section 5 Fuel System and Governor Inspection/Repair To clean vent ports, seats, etc., use a good. commercially available carburetor solvent, such as Gumout™, and clean, dry, compressed air to blow out internal channels and port. Use a suitable shop rag to prevent debris from hitting someone. Carefully inspect all components and replace those that are worn or damaged. + Inspect the carburetor body for cracks, holes, and other wear or damage. + Inspect the float for cracks, holes, and missing or damaged float tabs. Check the float hinge and shaft for wear or damage. + Inspect the fuel inlet needle and seat for wear or damage. +The choke plate is spring loaded. Check to make sure it moves freely on the shaft. Always use new gaskets when servicing or reinstalling carburetors. Repair kits are available which inciude new gaskets and other components. These kits are described below. Refer to the Parts Manual for the engine being serviced to ensure the correct repair kits and replacement parts are used. The Kohler part number is stamped on the choke side flange on top of the carburetor body. ‘Overhaul Kit With Gaskets Contains: Qty. |Description ‘Gasket, air cleaner base Gasket, carburetor Screw, throttle adjusting Gasket, chamber screw ‘Screw, idle adjusting Float Pin, float Valve, float Gasket, float chamber ‘Spring, throttle adjusting screw ‘Spring, idle adjusting screw Gasket, passage cover Choke Repair Kit With Gaskets Contains: Qty. |Description (Gasket, air cleaner base Gasket, carburetor ‘Screw, valve set ‘Valve, choke Filter, choke shaft ‘Spring, choke arm return Ring, choke lever Collar, choke Shaft, choke assembly Lover, choke assembly Gasket Kit With Gaskets Contains: aty. |Description Gasket, air cleaner base Gasket, carburetor Gasket, chamber screw Gasket, float chamber Gasket, passage cover Solenoid Replacement Kit With Gaskets Contains: Qty. |Description Gasket, air cleaner base Gasket, carburetor Gasket, solenoid Gasket, chamber screw Holder, solenoid Valve, solenoid Reassembly Procedure Reassembly is essentially the reverse of the disassembly procedure. Use new gaskets, springs, and adjusting screws as provided in the rep: ir kit. Also use new carburetor and intake manifold gaskets. 59Section 5 Fuel System and Governor Governor General ‘The #2 side camshaft is equipped with a centrifugal fiyball mechanical governor. Itis designed to hold the engine speed constant under changing load conditions. The governor works as follows: + Centrifugal force acting on the rotating governor assembly causes the flyballs to move outward as speed increases. + As the flyballs move outward, they exert increasing pressure against the cover and bushing. + The bushing contacts the yoke on the cross shaft causing the shaft to rotate, + One end of the cross shatt protrudes through the crankcase. The rotating action of the cross shaft Is transmitted to the throttle lever of the carburetor through the governor lever and external linkage. + When the engine is at rest, and the throttle isin the “Yast” position, the tension of the governor spring holds the throtle plate open. When the engine is operating and the governor assembly is rotating, the force applied against the cross shaft tends to close the throttle plate. The governor spring tension and the force applied by the bushing balance each other during operation to maintain engine speed. ‘+ When load is applied and the engine speed and ‘governor speed decrease, the governor spring tension moves the governor lever to open the throtle plate wider. This allows more fuel into the engine, increasing engine speed. As speed reaches the governed setting, the governor spring tension and the force applied by the bushing will again offset each other to hold a steady engine speed. Adjustments Gener ‘The governed speed setting is determined by the position of the throttle control. It can be variable or constant, depending on the engine application. ‘Cross Shaft Seal Figure 5-8. Internal Governor Components on #2 Side Camshaft. 5.10Section 5 Fuel System and Governor Initial Adjustment Make this adjustment whenever the governor lever is loosened or removed from the cross shaft. Adjust as follows: 1, Make sure the throttle inkages are connected to the governor lever, the bellerank, and the throttle lever on the carburetor. 2. Loosen the hex. nut holding the governor lever to the cross shaft 3. Move the governor lever TOWARDS the throttle control bracket as far as it will move (wide open. throttle) and hold in position, 4, Insert a nail into the hole on the cross shaft and rotate the shaft COUNTERCLOCKWISE as far as, ‘twill turn, then tighten hex. nut securely. Sensitivity Adjustment Governor sensitivity is adjusted by repositioning the governor spring in the holes on the governor lever. If speed surging occurs with a change in engine load, the governor is set too sensitive. Ifa big drop in speed ‘occurs when normal load is applied, the governor should be set for greater sensitivity. Adjust as follows: 1. To increase the sensitivity, move the spring closer to the governor lever pivot point. 2. To decrease the sensitivity, move the spring away from the governor lever pivot point. 5.11TH16 & TH18 Section 6 Lubrication System General This engine uses a full pressure lubrication system. This system delivers oil under pressure to the crankshaft, camshatts, and connecting rod bearing surfaces, Ahiigh-efficiency gerotor pump is located in the crankcase. The oil pump maintains high oil flow and oil pressure, even at low speeds and high operating temperatures. A pressure relief valve in the crankcase limits the maximum pressure of the system. Service ‘The two crankcase halves must be separated to service the oll pickup or the pressure relief valve Refer to the appropriate procedures in Section 9. Oil Recommendations Using the proper type and weight of oil in the crankcase is extremely important; so is checking oll daily and changing the oil and fiter regulary. Use high-quality detergent oil of API (American Petroleum Institute) service class SG or SH. Select the viscosity based on the air temperature at the time of operation as shown in the following table. RECOMMENDED SAE VISCOSITY GRADES 1 74 z oe So rfp RE EN oN ET TEPERATURE RANGE OIPECTED BEFORE NEXT OL CHANGE —] -Use of synthetic oil having SW-20 or 5W-30 rating is. lacceptable, up to 40°F. **Synthetic ols wil provide better starting in extreme cold (below -10°F). NOTE: Using other than service class SG or SH oil or extending oil change intervals longer than recommended can cause engine damage ‘A logo or symbol on oil containers identifies the API service class and SAE viscosity grade. See Figure 6-1 Figure 6-1. Oil Container Logo. The top position of the symbol shows service class such as API SERVICE CLASS SG. The symbol may show additional categories such as SH, CC, or CD. The center portion shows the viscosity grade such as SAE 10W-20. Ifthe botiom portion shows “Energy Conserving,” it means that ol is intended to improve fuel economy in passenger car engines. Checking Oil Level The importance of checking and maintaining the proper ol level in the crankcase cannot be overemphasized. Check oll BEFORE EACH USE as follows: 1. Make sure the engine is stopped, level, and cool 0 the oil has had time to drain into sump. 2. Clean the area around the dipstick before removing it. This will help to keep dirt, grass clippings, etc., out of the engine, 61Lubrication System 3. Remove the dipstick; wipe oil off. Reinsert the dipstick into the tube until fully seated. See Figure 62 (Starter Side). 4, Remove dipstick and check oil level. The level should be between the "F” and "L” marks. If low, add oil of proper type up to the full mark. Reinstall oil fill cap and dipstick. Figure 6-2. Location of Dipstick and Oil Drain Plug 74 F “F” Mark Operating Range Figure 6-3. Oil Level Marks on Dipstick. NOTE: To prevent extensive engine wear or damage, ‘always maintain the proper oil level in the crankcase. Never operate the engine with the oil level below the “L” mark or above the "F” mark on the dipstick. il Change: Overhead Valve For New Engines - change oil after the first 5 hours. of operation; then every 100 hours of operation thereafter. For Overhauled Engines or those rebuilt with a new Short Block or Miniblock - use 10W-30 weight (Kohler “Command”) - service class SG or SH for the first 5 hours of operation. Change the oil ater this intial run-in period. Refill wth service class SG or SH oil of viscosity specified under “Oil Types.” When changing oil, drain oil while the engine is stil warm from operation. The oil wil flow more freely and ‘carry away more impurities. Tit the engine slightly toward the oil drain and allow ample time for complete drainage. After draining, reinstall drain plug. Fill wth proper oil to the 'F” mark on the dipstick. Always check the level with the dipstick before adding more oil. Make sure engine is level when filing and checking oil, ES Figure 6-4. Location of Oil Drain on Oil Filter Side. Change the oil as follows: 1. Clean the areas around the drain plug, dipstick, and oil fil cap, 2, Remove one of the oil drain plugs. A drain plug is located on either side of the crankcase; one is below the oll fiter, and the other is below the starter. See Figure 6-4. 3. Allow all oil to drain and then reinstall the drain plug. Torque to 13.6 N-m (10 ft. Ib.). 4. Remove the oil fill cap and fll the engine with the proper oil to the “F” mark on the dipstick. Always heck the oil level with the dipstick before adding more oil, 5. Reinstall the ol fill cap. 62Section 6 Lubrication System igure 6-5. Removing Oil Filler. Changing Oil Fitter Replace the oil filter at least every other oil change (every 200 hours of operation). Always use a genuine Kohler oi filter. Change the oil fiter as follows (see Figures 6-5 and 6-6): 1. Clean areas around drain plug, oil fiter, dipstick, and oi fill cap. 2. Remove one of the oil drain plugs. A drain plug is located on either side of the crankcase; one is below the oil iter, the other is below the starter. 3. Allow all the oil to drain and then reinstall the drain plug. Tighten to 13.6 N'm (10 ft. Ib.) 4, Remove the old filter and wipe off the fier adapter with a clean cloth, 5. Place a new replacement filter in a shallow pan with the open end up. Pour new oll of the proper type in through the threaded center hole. Stop pouring when the oll reaches the bottom of the threads. Allow a minute or two for the oil to be absorbed by the filter material 6. Puta drop of oil on your fingertip and wipe it on the rubber gasket. Figure 6-6. Hand Tighten New Filler in Clockwise Direction. 7. Install the new oil filter to the filter adapter. Hand tighten the filter clockwise until the rubber gasket contacts the adapter, then tighten the filter an adcitional 1/2 turn. 8 Remove the oil fill cap and fill the engine with the proper oil fo the "F” mark on the dipstick. Always check the oil level with the dipstick before adding more oil Figure 6-7. Replenish Oil to Proper Level. 63Section 6 Lubrication System Figure 6-8. Reinstall Dipstick. 8 Reinstall the oil fil cap and dipstick. 9. Start the engine and check for oil leaks. Stop the engine, allow a minute for the oil to drain down, and recheck the level on the dipstick il Sentry™ General ‘Some engines are equipped with an optional Oil Sentry™ oil pressure switch monitor. If the pressure decreases below an acceptable level, the Oil Sentry™ will either shut off the engine or activate a warning, signal, depending on the application. ‘The pressure switch is designed to break contact as the oll pressure increases, and make contact as the oll pressure decreases. At oll pressure above approximately 3.0/5.0 psig, the switch contacts open. Below this pressure, the switch contacts close. (On stationary or unattended applications (pumps, generators, etc.), the pressure switch can be used to {ground the ignition module to stop the engine. On vehicular applications (lawn tractors, mowers, etc.) the pressure switch can only be used to activate a "iow cil” warning light, NOTE: Make sure the oil level is checked BEFORE EACH USE and is maintained up to the "F” mark on the dipstick. This includes engines equipped with Oil Sentry™ Installation ‘The Oil Sentry™ pressure switch is installed in the oil filter adapter. ‘On engines not equipped with Oil Sentry™ the installation hole is sealed with a 1/8-27 N.P.T.F. pipe plug. To install new switch, follow these steps: 1 Apply pipe sealant with teflon to the threads of the switch Hand start the switch into the tapped hole in the «il fiter adapter. See Figure 6-6 Torque the switch to a maximum 3.4 Nm (30 in. Ib.). Do not overtighten or you will crack the adapter. Testing Compressed air, a pressure regulator, pressure gauge, and a continuity tester are required to test the switch. 1 Connect the continuity tester across the blade terminal and the metal case ofthe switch. With Opsig pressure applied to the switch, the tester should incicate continuity (switch closed). Gradually increase the pressure to the switch. AS pressure increases through the range of 3.0/5.0 psig, the tester should indicate a change to no continuity (switch open). The switch should remain open as the pressure is increased to 90 psig maximum. Gradually decrease the pressure through the range of 3.0/5.0 psig. The tester should indicate a change to continuity (switch closed) down to Opsig. Replace the switch if it does not operate as specified 64TH16 & TH18 Section 7 Retractable Starter (BX wannine: spring Under Tension! relieving spring tension. Retractable starters contain a powertul, recoil spring that is under tension. Always wear safety ‘goggles when servicing retractable starters and carefully follow instructions in this section for Starter Housing Spring and _( Keeper —— ~ Pawi (Dog) Repair Kit &— center Screw Figure 7-1. Retractable Starter — Exploded To Remove Starter 1. Remove the five hex. flange screws securing the starter to blower housing. See Figure 7-2. 2. Remove the starter. Figure 7-2. Removing Retractable Starter. To Install Starter 1. Install the retractable starter and five hex. flange screws to blower housing. Leave the screws slightly loose. 2. Pull the starter handle out until the pawls engage in the drive cup. Hold the handle in this position and tighten the screws securely. Rope Replacement ‘The rope can be replaced without complete starter disassembly 1. Remove the starter from the engine blower housing, 2. Pullthe rope out approximately 12" and tie a temporary (siip) knot init to keep it from retracting into the starter. See Figure 7-3. 7ASection7 Retractable Starter L Figure 7-3. 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 slip knot. Allow the pulley to rotate slowly as the spring tension is released, 6. When all spring tension on the starter pulley is released, remove the rope from pulley. 6. Tie single knot in one end of the new rope. 7. Rotate the pulley counterclockwise (when viewed from pawl side of pulley) until the spring is tight. (Approximately 6 full turns of pulley.) 8. Rotate the pulley clockwise until the rope hole in pullay is aligned with rope guide bushing of starter housing, NOTE: Do not allow the pulley/spring to unwind, Enlist the aid of a helper it necessary, or use a C-clamp to hold the pulley in position. 9. Insert the new rope through the rope hole in starter pulley and rope guide bushing of housing, See Figure 7-4. Figure 7-4. Installing Rope. 10. " 12. Tie a slip knot approximately 12" from the free ‘end of rope. Hold the pulley firmly and allow it to rotate slowly until the slip knot reaches the guide bushing of housing. Slip the handle and rope retainer onto the rope. Tie a single knot at the end of the rope. install the rope retainer into the starter handle. Untie the slip knot and pull on the handle until the rope is fully extended. Slowly retract the rope into the starter. When the spring is properly tensioned, the rope will retract fully and the handle will stop against the starter housing Pawls (Dogs) Replacement To replace the pawls, follow disassembly steps 1-4 and reassembly steps 3-8 on the folowing pages. A pawl repair kit is available which includes the following ‘components: Paw! Repair Kit, aty. Description 1 | Dog Cam 1 | Center Screw 2 | Paw! (Dog) Spring 1 | Brake Spring 2 | Starter Pawi (Dog) 1 | Brake Washer 1_| Washer 72Section 7 Retractable Starter Disassembly AX warnina: spring Under Tension! Do not remove the center screw from 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 o ensure personal safety and proper starter disassembly. Make sure adequate face protection is worn by all persons in the area. 1. Release spring tension and removethe nandie and starter rope. (Refer to "Rope Replacement,” steps 2 through 5 on pages 7.1 and 7.2.) 5 2. Remove the center screw, washer, and paw! retainer. See Figure 7-5. 3. Remove the brake spring and brake washer. See g Figure 7-6. 4. Carefully note the positions of the pawis and paw! springs before removing them. 7 Remove the pawls and pawl springs from the starter pulley. are aa ry \ 6 Ce Figure 7-5. Center Screw, Washer and Pawl Retainer. igure 7-6, Brake Spring and Washer and Pawls. Rotate the pulley clockwise 2 full turns. This will ensure the spring is disengaged from the starter housing. Hold the pulley into the starter housing. Invert the pulley/housing so the pulley is away from your face, and away from others in the area. Rotate the pulley slightly from side to side and carefully separate the pulley from the housing, See Figure 7-7. Ht the pulley and the housing do not separate ‘easily, the spring could be engaged in the starter housing, or there is still tension on the spring. Return the pulley to the housing and repeat step 5 before separating the pulley and housing. Figure 7-7. Removing Pulley from Housing. 73Section 7 Retractable Starter Note the position of the spring and keeper assembly in the pulley. See Figure 7-8. Remove the spring and keeper assembly from the pulley as a package. &\ wanwinc: spring Under Tension! Do not remove the spring from the keeper. Severe personal injury could result rom the sudden uncoiling of the spring. Figure 7-8. Position of Spring and Keeper in Pulley. Inspection and Service 1. Carefully inspect the rope, paws, housing, center screw, and other components for wear or damage. 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. Do not attempt to rewind a spring that has come ‘out of the keeper. Order and install a new spring and keeper assembly. Clean all old grease and dirt from the starter ‘components. Generously lubricate the spring and, center shaft with any commercially available bearing grease. Reassembly 1. Make sure the spring is well lubricated with grease. Place the spring and keeper assembly inside the pulley (with spring towards pulley). See Figure 7-9. Install the pulley with spring and keeper assembly into the starter housing. See Figure 7-9. Make sure the pulley is fully seated against the starter housing. Do not wind the pulley and recoil spring at this time. Figure 74 Housing. Installing Pulley and Spring into 3 Install the pawl springs and pawis into the starter pulley. See Figure 7-10. Ce Figure 7-10. Installing Pawis and Paw! Springs. 4. Place the brake washer in the recess in starter pulley; over the center shaft 74Section7 Retractable Starter Lubricate the brake spring sparingly with grease. Place the spring on the plain washer. (Make sure the threads in center shaft remain clean, dry, and free of grease and oil.) Apply a small amount of Lectite® No. 271 to the threads of the center screw. Install the center screw, with washer and retainer, to the center shaft. Torque the screw to 7.4/8.5 N'm (65175 in. Ib.) Tension the spring and install the rope and handle as instructed in steps 6 through 12 under "Rope Replacement” on page 7.2. Install the starter to the engine blower housing. See Figure 7-11 Figure 7-11. installing Retractable Starter. 75TH16 & TH18 Section 8 Electrical System and Components This section covers the operation, service and repair of the electrical system components. Systems and components covered in this section are: + Spark Plugs + Battery and Charging System + Electronic CD Ignition System + Electric Starter Spark Plugs Engine misfire or starting problems are often caused by a spark plug that has improper gap setting or isin poor condition. ‘The engine is equipped with the following spark plugs: Champion® RC12YC (or equivalent) 0.76 mm (0.030 in.) 14mm 19.1 mm (3/4 in.) 15.9 mm (5/8 in.) Spark Plug Service Every 200 hours of operation, remove each spark plug. Check its condition and either reset the gap or replace with a new plug as necessary. To service the plugs, perform the following steps: 1. Before removing each spark plug, clean the area around the base of the plug to keep dirt and debris out of the engine. 2, Remove the plug and check its condition. See “Inspection” following this procedure, Replace the plug if necessary. NOTE: Do not clean spark plug in a machine using abrasive grit. Some grit could remain in the spark plug and enter the engine causing extensive wear and damage. 3. Check the gap using a wire feeler gauge. Adjust the gap to 0.76 mm (0.030 in.) by carefully bending the ground electrode. See Figure 8-1 Wire Gauge —— ‘Spark Plug Ground Electrode ——— 0.76 mm (0.030 in.) Gap Figure 6-1. Servicing Spark Plug. 4, Reinstall the spark plug into the cylinder head and tighten to 24.4/29.8 N-m (18/22 ft. Ib.) a4Section 8 Electrical System and Components Inspection Inspect each spark plug as itis removed from the cylinder head. The deposits on the tip are an indication of the general condition of the piston rings, valves, and carburetor Normal and fouled plugs are shown in the following photos: Carbon Fouled: Soft, sooty, black deposits indicate incomplete combustion caused by overrich carburetion, weak ignition, or poor compression. ‘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. Worn: On a worn plug, the center electrode will be rounded and the gap will be greater than the specified ‘gap. Replace a worn spark plug immediately. 82Section 8 Electrical System and Components in the combustion chamber. Excess fuel could be caused by a carburetor problem, or operating the engine with too much choke. Oil in the combustion chamber is usually caused by a breather problem, worn piston rings or valve guides. Overheated: Chalky, white deposits indicate very high combustion temperatures. This condition is usually accompanied by excessive gap erosion. Lean carburetor settings, an intake air leak, or incorrect, spark timing are normal causes for high combustion temperatures. Battery General AA 12 volt battery with a minimum of 250 cold-cranking amps should be sufficient for cranking. The actual cold cranking requirement depends on engine size, application and starting temperatures. Cranking requirements increase as temperatures decrease and battery capacity shrinks. Refer to the operating instructions of the equipment this engine powers for specific battery requirements. Ifthe battery charge is not sutficient to turn over the engine, recharge the battery. Battery Maintenance Regular maintenance is necessary to prolong battery lite, By wasnnc: expiosive cas! Batteries produce explosive hydrogen gas while being charged. To prevent a fire or explosion, charge batteries only in well ventilated areas. Keep sparks, ‘open flames, and other sources of ignition away from the battery at all times. Keep batteries out of the reach of children. Remove all jawelry 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 which could cause an explosion if hydrogen gas or gasoline vapors are present. 1. Regularly check the level of electrolyte. Add. distilled water as necessary to maintain the recommended level NOTE: Do not overill the battery. Poor performance or early failure due to loss of electrolyte will result. 2. Keep the cables, terminals, and external surfaces of the battery clean. A build-up of corrosive acid or grime on the external surfaces can cause the battery to self-discharge. Self-discharge occurs rapidly when moisture is present. 83Section 8 Electrical System and Components 3. Wash the cables, terminals, and external surfaces with a mild baking soda and water solution. Rinse thoroughly with clear water. NOTE: Do not allow the baking soda solution to ‘enter the cells as this will destroy the electrolyte. Battery Test To test the battery, you will need a DC voltmeter. Pertorm the following steps (see Figure 8-2): 1. Connect the voltmeter across the battery terminals. 2. Crank the engine. Ifthe battery drops below 9 volts while cranking, the battery is discharged or faulty. Electronic CD Ignition Systems Operation of CD Ignition Systems This system consists ofthe following components. DC Voltmeter Battery Figure 8-2. Battery Voltage Test. + Amagnet assembly which is permanently atfixed to the flywheel. + Two electronic capacitive discharge ignition modules which mount on the engine crankcase (Figure 8-3) + Akill switch (or key switch) which grounds the modules to stop the engine. + Two spark plugs. a4Section 8 Electrical System and Components .008/.012 in. (201.30 mm) Air Gap Ignition Modules Flywheel Figure 6-3. Capacitive Discharge Ignition System. top dead center. ‘The timing of the spark is controlled directly by the location of the flywheel magnet group as referenced to engine Figure 8-4. Capacitive Discharge Ignition Module. Operation: As the flywheel rotates, the magnet grouping passes the input coil (L1). The corresponding magnetic field induces energy into the input coil (L1). The resultant pulse is rectified by D1 and charges capacitor C1. As the magnet assembly completes its pass, it activates the triggering device (L2), which causes the semiconductor ‘switch (SCS) to turn on. With the device switch “ON,” the charging capacitor (C1) is directly connected across the primary (P) of the output transformer (T1). As the capacitor discharges, the current initiates a fast rising flux field in the transformer core. A high voltage pulse is generated from this action into the secondary winding of the transformer. This pulse is delivered to the spark plug gap. Ionization of the gap occurs, resulting in an arc at the plug electrodes. This spark ignites the fuel-air mixture in the combustion chamber. 85Section 8 Electrical System and Components Troubleshooting CD Ignition Systems The CD ignition systems are designed to be trouble free tor the lite of the engine. Other than periodically checkingjreplacing the spark plugs, no maintenance or timing adjustments are necessary or possible. Mechanical systems do occasionally fail or break down, however, so the following troubleshooting information is provided to help you get to the root of a reported problem, B wasninic:Etetrcat shock! Never touch electnical wires or components while the engine is running. They can be sources of electrical shock Testing Procedure Reported ignition problems are most often due to poor Connections. Before beginning the test procedure, check all external wiring. Be certain all ignition-related Wires are connected, including the spark plug leads. Be certain all terminal connections fit snugly. Make sure the ignition switch isin the run position. NOTE: The CD ignition systems are sensitive to excessive load on the kill lead. Ia customer complains of hard starting, low power, or re under load, it may be due to excessive ‘draw on the kil circuit, Disconnect any auxiliary kill wires or safety switches connected to the kill circuit and operate the engine fo determine if the reported problem is gone. Test Conclusion 4. Test for spark on both cylinders with Kohler ignition tester, Part No. 24 455 02. Disconnect one spark plug lead and connect it to the post terminal of the tester. Connect the clip to a good ground, not to the spark plug. Crank the engine and observe the tester spark gap. Repeat the procedure on the other cylinder. Remember to reconnect the first spark plug lead. m7 kel Ground clip (ar) L_] | | 3 Post Terminal 1. Ifone side is not fring, check all wiring, connections, and terminations on that side. If wiring is okay, replace ignition module and retest for spark, ifthe tester shows spark, but the engine misses or won't run on that cylinder, try a new spark plug. It neither side is fring, check for shorted kill lead, or faulty ignition switch. 86Section 8 Electrical System and Components Battery Charging Systems General These engines are equipped with either a 15 amp or 25 amp regulated battery charging system. See Figure 8-5 for the 15 amp system with panel giagram and Figure 8-6 for the 15/25 amp system without panel diagram NOTE: Observe the folowing guidelines to avoid damage to the electrical system and components: + Make sure the battery polarity is correct. A negative (-) ground system is used. + Disconnect the rectfr-regulator leads andior wiring harness plug before doing electric welding on the ‘equipment powered by the engine. Also, disconnect other electrical accessories in common ground with the engine. + Prevent the stator (AC) leads from touching or shorting while the engine is running. This could damage the stator. ed we ieee | wang DOA — oo J genes A gurane “ ner ° om poutine Teri, | seman BR © suscicmeioa | Emmety ma oe g = IT = Po Aa an Ee GL OY [N Ses Groune-—~ as” — ) | 7 I FOS =] : Ee Toon! | Figure 8-5. 15 amp Regulated Charging System With Panel. a7Section 8 Electrical System and Components Ganenonnme Figure 8-6. Wiring Diagram - 15/25 amp Regulated Battery Charging System Without Panel. 88Section 8 Electrical System and Components Rectifier-Regulator 15 Amp Stator Rectifier-Regulator AC Leads 25 Amp Stator Figure 8-8. 25 amp Stator and Rectifier-Regulator.Section 8 Electrical System and Components Troubleshooting Guide 15/25 amp Battery Charging System 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 withthe battery. NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should be made with the engine running at 3600 RPM - no load. The battery must be fully charged. Problem Test Conclusion No Charge Batlery “Trace B+ load trom rectiier-regulator to key switch, or other accessible connection Disconnect it from switch or connection. ‘Connect an ammeter from loose end of Bs lead to positive terminal of battery. Connect DC voltmeter from loose end of B+ lead to negative terminal of battery. With engine running at 3600 RPM, read voltage on voltmeter. If voltage is 13.8 volts or more, place a minimum load of 5 amps" on battery to reduce voltage. Observe ammeter. “NOTE: Turn on lights, if 60 watts or more. Or place a 2.5 ohm, 100 watt resistor across battery terminals. If voltage is 13.8-14.7 and charge rate increases when load is applied, the charging system is OK and battery was fully charged. If voltage is loss than 13.8 or charge rate does not increase when load is applied, test stator (Tests 2 and 3). 2. Remove connector from reciiierregulator. | 2 if vollage is 28 volts or more, stator is OK ‘With engine running at 3600 RPM, measure FRectifier-regulator is faulty. Replace the AC voltage across stator leads using an AC recttier-regulator. voltmeter. It voltage is less than 28 volts, stator is probably faulty and should be replaced. Test stator further using an ohmmeter (Test 3) ‘3a. With engine stopped, measure the resistance [3a._If resistance is .064/0.2 ohms, the stator is OK across stator leads using an ohmmeter. {tthe resistance is infinity ohms, stator is ‘open. Replace stator. ‘3b. With the engine stopped, measure the '3b. If the resistance is infinity ohms (no resistance from each stator lead to ground Using an ohmmeter. Continuity), the stator is OK (not shorted to ground). It resistance (or continuity) Is measured, the stator leads are shorted to ground. Replace stator. Battery Continuously Charges at High Rate Parform same test as step 1 above. Tr the voltage is 14:7 volts or less the charging system is OK. The battery is unable to hold a charge. Service battery or replace as necessary. It voltage Is more than 14.7 volts, the rectiier- regulator is fauily. Replace reciier-ragulator. 8.10Section 8 Electrical System and Components Stator ‘The stator is mounted on the crankcase behind the flywheel. Should the stator have to be replaced, follow the procedures in Section 9 “Disassembly.” See Figure 8-7 for 15 amp stator or Figure 8-8 for 25 amp stator. Rectifier-Regulator ‘The rectifier regulator is mounted on the blower housing on standard engines, and on the valley baffle on top tank engines. To replace it, disconnect the plug, remove the two mounting bolts and ground strap. DC Voltmeter Flywheel Stator Battery ‘igure 6-9, Connections for Testing Charging System. a1Section 8 Electrical System and Components Electric Starting Motors ‘Some engines in this series use inertia drive type starting motors while others use solenoid shit type, The inertia drive types are covered first and the solenoid shift type is covered starting on page 8.16. Starting Motor Precautions NOTE: Do not erank the engine continuously for more than 10 seconds at a time. Ifthe engine does not start, allow a 60 second cool-down period between starting attempts. Failure to follow these guidelines can burn out the starter motor. NOTE: Ifthe engine develops sufficient speed to disengage the inertia drive type starter but does not keep running (a false start), the engine rotation must be allowed to come toa complete stop before attempting to restart the engine. Ifthe starter is engaged while the flywheel is rotating, the starter pinion and flywheel ring gear may clash, resulting in damage to the starter. Troubleshooting Guide - Starting Difficulties NOTE: If the starter does not crank the engine, shut off the starter immediately. Do not make further attempts to start the engine until the condition is corrected. NOTE: Do not drop the starter or strike the starter frame. Doing so can damage the starter. Starter Removal and Installation Refer to the “Disassembly” and *Reassembly" Sections for starter removal and installation procedures, Inertia Drive Electric Starters ‘This subsection covers the operation, troubleshooting, and repair ofthe inertia drive permanent magnet electric starters from United Technologies (UT). Problem Possible Fault Correction Battery 1. Check the specitic gravity of battery. If low, recharge or replace battery as necessary. Starter Does Not Clean corroded connections and tighten loose connections. Energize ing 2. Replace wires in poor condition and with frayed or broken insulation. Starter Switch or Solenoid Bypass the switch or solenoid with a jumper wire. If starter cranks normally, replace the faulty components. Starter Energizes But Turns Slowly Battery Check the specific gravity of battery. If low, recharge or replace battery as necessary. Battery too small, must be at least 250 cold-cranking amps, Brushes Check for excessively dirty or worn brushes and commutator. Clean using a coarse cloth (not emery cloth). Replace brushes if excessively or unevenly worn, Make sure the clutch or transmission is disengaged or placed in neutral. This is especially important on equipment with hydrostatic drive. The transmission must be exactly in neutral to prevent resistance which could keep the engine from starting, Check for seized engine components such as the bearings, connecting rod, and piston 812Section 8 Electrical System and Components Operation - Inertia Drive Starters When power is applied to the starter, the armature rotates. As the armature rotates, the drive pinion ‘moves out on the splined drive shaft and into mesh with the flywheel ring gear. When the pinion reaches the end of the drive shatt, it rotates the flywheel and “cranks” the engine. When the engine starts, the flywheel rotates faster than the starter armature and drive pinion. This moves the drive pinion out of mesh with the ring gear and into the retracted position. When power is removed trom the starter, the armature stops rotating and the drive pinion is held in the retracted position by the anti-drift spring. Service the drive as follows: Dust Cover ~Spring Retainer, Retaining Ring _-Anti-Drift Spring Dust Cover spacer (Collar) igure 6-10. UT Inertia Drive Electric Starter. UT Starter Drive Service Every 500 hours of operation (or annually, whichever ‘occurs first), clean and lubricate the splines on the starter drive shatt, If the drive pinion is worn, or has chipped or broken teeth, it must be replaced. Itis not necessary to completely disassemble the starter to service the drive components, but itis. necessary to remove the starter from the engine. Tape the commutator end cap to the starter frame, so they cannot separate when the bolts are loosened for removal. Remove the starter. Figure 8-11. Drive Components, UTE “Bonded” Inertia Drive Starter. 1. The rubber dust cover has a molded lip on the inside that snaps into a groove in the dust cover spacer (See Figure 8-11). Turn the drive pinion clockwise unti it reaches the fully extended position. While holding it in the extended position, grasp the tip of the dust cover with a pliers or vise rip and pull it free from the spacer. 2. Disassemble removal tool, 25761 18, by loosening the center screw one or two turns and. removing the outer collar. 3. Again referring to Figure 8-11, grasp the spring retainer and push it toward the starter, ‘compressing the anti-drft spring and exposing the retaining ring. 8.13Section 8 Electrical System and Components 4. Holding the spring retainer in the retracted position, assemble the inner halves of the removal tool around the armature shaft with the retaining ring in the inner groove (see Figure 8-12). Slide the collar over the inner halves to hold them in position. Figure 6-12. Assembling Inner Half of Too! Around ‘Armature Shaft and Retaining Ring. 5. Thread the center screw into the removal tool until you feel resistance. Use a wrench (1-1/8" or adjustable) to hold the base of the removal tool. Use another wrench or socket (1/2" or 13 mm) to turn the center screw clockwise (see Figure 8-13). The resistance against the center screw will tell you when the retaining ring has popped out of the groove in the armature shatt. Figure 6-13. Holding Tool and Turning Center Screw (Clockwise) to Remove Retaining Ring. 6. Remove the drive components from the armature shaft, paying attention to the sequence. Ifthe splines are dirty, clean them with solvent. 7. The splines should have a light film of lubricant. Relubricate as necessary with Kohler bendix starter lubricant (Part No, 52 357 01). Reinstall or replace the drive components, assembling them in the same sequence as they were removed. Retaining Ring Installation 1. Position the retaining ring in the groove in one of the inner halves of tool 25 761 18. 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. Slip the tool over the end of the armature shaft, so the retaining ring inside is resting on the end of the shaft. Hold the tool with one hand, exerting slight pressure toward the starter. Tap the top of the tool with a hammer until you fee! the retaining ring snap into the groove. Disassemble and remove the tool. 4, Assemble the inner halves with the larger cavity around the spring retainer (see Figure 8-14). Slide the collar over them and thread the center screw in until resistance is felt Figure 8-14. Assembling Larger inner Half Aroun Spring Retainer. 5. Hold the base of the tool with a 1-1/8" wrench and. tur the center screw clockwise with a 1/2" or 13, ‘mm wrench to draw the spring retainer up around the retaining ring. Stop turning when resistance increases. Disassemble and remove tool. 6. Reinstall the dust cover. ataSection 8 Electrical System and Components UT Starter Disassembly 1 Remove the dust cover, retainer ring, spring retainer, anti-drft spring, dust cover spacer, and drive pinion. Refer to “UT Starter Drive Service” starting on page 8.13. Remove the thru bolts. Remove the commutator end cap with brushes and brush springs. Remove the drive end cap. Remove the armature and thrust washer from Inside the starter frame, UT Brush Replacement 1 Remove the brush springs from the pockets in brush holder. See Figure 8-15. [Stud Terminal With Positive (+) Brushes ‘Brash Springs Self-Tapping f ae Screw zrmal Brush \ Holder Negative (-) Brush Selt-Tapping Screw 5. Install the brush holder, new negative (-) brushes, and sel-tapping screws, 6. Install the brush springs and brushes into the pockets in brush holder. Make sure the chamfered sides of brushes are away from the brush springs, NOTE: Use a brush holder too! to keep the brushes in the pockets. A brush holder tool can easily be made from thin sheet metal. See Figure 816, Figure 8-15. Commutator End Cap with Brushes. 2, Remove the selt-tapping screws, negative brushes, and plastic brush holder. y Remove the hex, flange nut and fiber washer from the stud terminal Remove the stud terminal with positive (+) brushes and plastic insulating bushing from the end cap, Reinstall the insulating bushing to the new stud terminal with positive (+) brushes. Install the stud terminal with bushing into the commutator end cap. Secure the stud with the fiber washer and hex. flange screw. Figure 8-16. Brush Holder Tool (For UT Starters). UT Commutator Service Clean the commutator with a coarse, lint free cloth. Do not use emery cloth. If the commutator is badly worn or grooved, turn it down on a lathe or replace the armature. UT Starter Reassembly 1, Place the thrust washer over the drive shaft of armature. 2. Insert the armature into the starter frame, Make sure the magnets are closer to the drive shatt end of armature. The magnets will hold the armature inside the frame. 8.15Section 8 Electrical System and Components. 3, Install the drive end cap over the drive shaft Make sure the match marks on the end cap and starter frame are aligned. See Figure 8-17. The small notch in the edge of the end cap, adjacent to the match mark, will engage a small tang inside the end of the starter frame. Match Marks ‘gb Figure 8-17. UT Starter Assembly Match Marks. 4, Install the brush holder too! to keep the brushes in the pockets of the commutator end cap. 5. Align the terminal stud on the commutator end ‘cap with the long scribe mark on the starter frame. Hold the drive end and commutator end Caps firmly to the starter frame. Remove the brush holder tool 6. Install the thru bolts and tighten securely. 7. Lubricate the drive shaft with Kohler electric starter drive lubricant. Install the drive pinion, dust cover spacer, anti-drift spring, spring retainer, retaining ring, and dust cover. Refer to “UT Starter Drive Service” on page 8.13. Solenoid Shift Electric Starter This subsection covers the solenoid shift electric starter. Much of the information in the preceding subsection relates to this starter, therefore itis not repeated here. Please use the exploded view (Figure 8-18) for reference during the disassembly and assembly procedure, Operation When power is applied to the starter, the electric solenoid moves the drive pinion out onto the drive shaft and into mesh with the flywheel ring gear. When the pinion reaches the end of the drive shaft rotates the flywheel and cranks the engine. When the engine starts and the start switch is released the starter solenoid is deactivated, the drive lever moves back, and the drive pinion moves out of mesh with the ring gear into the retracted position, Magnet Switch Rear Stop Collar ‘\. Retainer Front Stop Collar Rear Bushing iP \ KY eulator \, ‘Brush Spring — Cover ~SThru Bolt Brush Holder Figure 8-18. Exploded View of Solenoid Shift Starter. 8.16Section 8 Electrical System and Components Starter Removal and Reinstallation Refer to the engine disassembly and reassembly sections later in this manual for starter removal and installation procedures. Starter Disassembly 1. Disconnect the wire from the solenoid, 2. Remove the hex. nuts securing the solenoid, and remove the solenoid from the starter assembly. 3, Remove the two thru bolts. 4. Remove the commutator end cap. 5. Remove the insulator and brush springs from the brush spring holder. Insulator Brush Spring Brush Figure 8-19. Removing the Insulator. 6. Remove the armature from the frame. 7. Remove the drive lever and armature from the drive end cap. Drive Lever. Figure 6-20. Removing the Armature and Drive Lever. Front Stop Collar Retainer. Rear Stop Collar Figure 6-21. Stop Collars and Retainer. 8, The stop collar consisis of two pieces. The rear stop collars held in place by being snapped over a retainer. The retainer is held in place by a groove in the armature shaft. The front stop collar rests against the rear stop collar. Side the front stop collar off of the armature shat. See Figure 8-22. Use a 1/2" or 13 mm deep socket and plastic hammer and tap the rear stop collar down to separate it from the retainer. See Figure 8-23, Fron Stop Collar ~ Figure 8-22. Removing the Front Stop Collar. 8.17Section 8 Electrical System and Components Plastic Hammer 1/2" (13 mm) — Deep Socket, Trim off Figure 8-23, Separating the Rear Stop Collar From the Retainer. 9. After the stop collars are removed, the retainer can be removed from the armature shaft. Do not reuse the retainer. Brush Replacement The brushes in the starter are part of the starter frame, brush kit Part No. 52 221 01 contains four replacement brushes and springs. If replacement is necessary, all four brushes should be replaced Figure 8-24. Replacement Brush. 1. Remove brushes from brush holder, and remove brush holder from frame. Figure 8-25. Cutting Brush Lead Wires From the Frame Posts. 2. Cutthe brush lead wire at the edge of the post with a pair of nippers. 3. File off burrs on the post. lan Remove Burrs Figure 8-26. Filing Off Burrs on Posts. 4. Place the plate of the spare brush on the welded portion of the brush lead wire, and then crimp them together with a pair of pliers. Be sure to align the edge of the lead wire 8.18Trimmed Edge \\_ Spare Brush Plate — Crimp Figure 6-27. Connecting Replacement Brushes. Soldering Iron Figure 6-28. Soldering Brush Clips To Posts. Section 8 Electrical System and Components 5. Solder the crimped portion to the post. 6. Replace the brush holder in the frame and place the brushes in the brush holder. Reinstall the springs, Retainer Rear Stop Collar igure 6-29. Installing Retainer. ‘Starter Service Clean drive lever and armature shatt; then apply Kohler electric starter drive lubricant or equivalent to lever and shaft. Starter Reassembly 1. Insert the rear stop collar on the armature shaft 8.19Section 8 Electrical System and Components Engine oll Grease Engine Oil Figure 6-30. Lubrication Points. _—Stop Collars| Pliers ~ —~Pliers Figure 6-31. Tightening the Retainer. 2. Install new retainer in the groove on the armature shaft. NOTE: Always use a new retainer. Tighten the retainer in the groove to secure. Figure 8-32. Installing the Stop Collar 3. Fit the front stop collar over the shaft and bring the front and the rear stop collars together over the retainer. Using two pairs of pliers, apply even force to the two collars until they snap over the retainer and nest into one another. 8.20Section 8 Electrical System and Components _-7 Brush Spring Figure 8-33. Installing the Brush Springs. 4. Reassemble the remaining components of the starter in reverse order of disassembly. 8.21TH16 & TH18 Section 9 Disassembly AD warns: accidental stars! Before servicing the engine or equipment, always disconnect the spark plug lead(s) to prevent the engine from starting accidentally. Ground the leads to prevent sparks that could cause fires. Make sure the ‘equipment is in neutral General Clean all parts thoroughly as the engine is disassembled, Only clean parts can be accurately inspected and gauged for wear or damage. There are many commercially available cleaners that will quickly remove grease, oil and grime from engine parts. When such a cleaner is used, follow the manufacturer's instructions and safety precautions carefully, Make sure all traces of the cleaner are removed before the engine is reassembled and placed into operation. Even small amounts of these cleaners can quickly break down the lubricating properties of engine oil Typical Disassembly Sequence The following sequence is suggested for complete engine disassembly. The sequence can be varied to accommodate options or special equipment. Disconnect spark plug leads, Turn fuel shut-off valve to “off” position Drain oil from crankcase and remove oil filter. Remove air cleaner assembly. Remove fuel tank (it so equipped). Remove muttler (if so equipped) Disconnect carburetor linkage. Remove retractable starter or grass screen. Remove blower housing. 10, Remove electric starter motor, 11, Remove side baffles. 12, Remove ignition modules. 13. Remove flywheel 14, Remove stator 18. Remove timing belt 16. Remove valve covers. 17. Remove #1 side camshatt Senonaens 18. Remove rocker arms. 19. Remove #2 side camshaft, 20. Remove governor yoke. 21. Remove rectitior-regulator. 22. Remove valley baffle. 23. Remove crankcase breather. 24. Remove Oil Sentry Switch. 25. Remove oil filter adapter. 26. Separate crankcase halves. 27. Remove oil pump parts. 28, Remove oil pressure relief parts. 29. Remove connecting rods. 30. Remove crankshaft 31. Disassemble crankshaft, 32. Remove piston assemblies, 33, Remove valve train parts. Disconnect Spark Plug Leads 1. Disconnect the leads from the spark plugs. See Figure 9-1 NOTE: Pull on boot only, to prevent damage to spark plug lead. Figure 9-1. Disconnect Both Spark Plug Leads. 94Section 9 Disassembly Turn Fuel Off 1. Turn fuel shut-off valve to off position. Vertical position is off. See Figure 9-2. Figure 9-2. Turn Fuel Off. Drain Oil From Crankcase and Remove Oil Filter 1. Remove oil fill cap and one of the oil drain plugs. See Figure 9-3 for location of drain on oil filter side. |. Removing Oil Drain Plug and Filter. 2. Allow ample time for al of the oil to drain from the crankcase and oil filter. 8. Remove the oil fter by turing itin a counterclockwise direction with a filter wrench. Discard fier. Remove Air Cleaner Assembly 1. Remove air cleaner components from base plate. Refer to Section 4, Remove the air cleaner base from carburetor elbow by removing the three hex. flange screws. See Figure 9-4, Remove the base plate. Some early engines may also have a spacer between the base plate and elbow, Figure 9-4. Removing Base Plate (Standard Type Shown). 3. Discard the base plate to carburetor gasket Remove Fuel Tank (If So Equipped) 1. On engines equipped with the top-mounted fuel tank, remove the five hex. flange screws securing the tank to the valve covers. 2. Lift the tank and pull it forward. Fuel line will come with it, See Figure 9-5, Figure 9-5. Removing Engine-Mounted Fuel Tank. 3. Loosen hose clamp holding fuel line to the fuel shut-off valve, then separate hose and remove fuel tank 92Section 9 Disassembly Remove Muffler Disconnect Carburetor Linkage 4. Onengine so equipped, remove the muffler from 41. Loosen the hose clamp holding the upper end of engine by removing the four hex. flange nuts (2 the breather hose on the flange of the carburetor on each side) with a 13 mm flex socket. See elbow. Pull the end off the tlange. See Figure 9-7, Figure 9-6. Figure 9-7. Disconnecting Breather Hose. Figure 9-6. Removing Muffler. 2. Carefully disconnect the flanged lower end of the 2. Remove and discard the two exhaust gaskets. hose from the breather cover. Remove the hose. 3. Loosen the hex. flange nut and slide the governor lever off of the governor shaft ‘Serew Bushing) Governor Lever Nut — Location “8 Governor Link,” (Choke Cable Fastener & Clamp) Bushing Location “A” Bushing \ “Screw & Clamp Linkage Spring Throttle Link — Choke Lever Contrai\. S82" Bracket Wave Washor Governor Pivot Lever Sorew ~ Spacer Spacer ‘Serew i Control Lever Spacer Figure 9-8. Standard Throttle Control Detail. 93Section 9 Disassembly Disconnect the fuel line from the carburetor by sing a needle nose pliers to loosen the hose clamp. Remove the two hex. flange nuts from the carburetor mounting studs. On engines without a top tank, thread the carburetor nuts, flanges facing, onto the stud protruding from the top of the crankcase, “Jam” them together and then turn the lower one counterclockwise to remove the stud Slide the intake elbow, carburetor, and spacer off the mounting studs on the intake manifold, Lift the carburetor and control bracket assembly and disconnect the leads from the fuel shut-off solenoid. Remove the carburetor, control bracket, governor lever, and attached linkages as an assembly. If further service of the components is necessary, the assembly can be broken down following steps. et Unsnap the linkage bushing and disconnect the throttle link and linkage spring from the pivot lever. Soe Figure 9-8. Disconnect choke link from carburetor and choke lever. Unsnap the bushing and disconnect the governor link from the pivot lever. Mark the hole position of the governor spring in the governor lever and governor pivot fever. Remove the spring, Remove Retractable Starter or Grass Screen 1. On engines so equipped, remove the retractable starter from blower housing by removing the five mounting screws. Note the position of the starter handle to reinstall it later. See Figure 9-9. Figure 9-9. Remove Retractable Starter. 2. Onengines with a grass screen, either unsnap the screen or remove the screws holding it to the flywheel fan Remove Blower Housing 4. the rectifier-regulator is mounted to the blower housing, remove the left screw to disconnect the ground lead. Remove the biower housing by removing the six hex. flange screws and two hex, flange nuts (in recesses at top front of housing) Make note of location of the two shorter screws. See Figure 9-10. Figure 9-10. Removing Blower Housing. a4Section 9 Disassembly Remove Electric Starter 1. Ifthe engine is equipped with a cranking solenoid, disconnect all leads, remove the two hex. flange mounting screws, and remove the solenoid. See Figure 9-11 Figure 9-11. Removing Solenoid 2. The starter thru bolts are also the mounting bolts. ‘Tape the end caps to the frame to prevent them from separating when the bolts are loosened. 3. Remove the top 3/8" Figure 9-12, mounting screw as shown in Figure 9-12. Removing Starting Motor. 4. Loosen the bottom 3/8" mounting screw just enough to remove the starting motor. Do not completely remove the mounting screw from starter Remove Side Baffles 1. Remove the single screw holding the side baffle to the #2 cylinder and remove the baffle. See Figure 9-13, Figure 9-13. Removing #2 Side Baffle, 2. To remove the #1 side baffle, loosen the two ‘screws holding the wire connector and slide the connector off, 3. Remove the side baffle from the #1 cylinder. See Figure 9-14, Figure 9-14, Removing #1 Side Baffle. Remove Ignition Modules 4. Turn the flywheel magnet away from the ignition modules. 2. Disconnect the white “kill” leads, 95Section 9 Disassembly 3. Remove the two hex. flange mounting screws from each module and remove both modules. See Figure 9-15. Figure 9-15. Removing Ignition Modules (#1 Side Shown). Remove Flywheel NOTE: Always use a flywheel strap wrench or holding tool to hold the flywheel when loosening or tightening the flywheel screw. Do not use any type of bar or wedge to hold the flywheel. Use of such tools could cause the flywheel to become cracked or damaged 1. Hold flywheel with a strap wrench or holding tool (refer to Section 2). Turn flywheel retaining screw (13 mm socket) counterclockwise to remove sorew and washer, Engines with retractable starters will also have the drive cup retained with, the flywheel screw. See Figure 9-16 Figure 9-16. Remove Cup From Retractable Starter, Equipped Models. 96 2. Use a flywheel puller to separate flywheel from crankshaft taper. See Figure 9-17. Figure 9-17. Using Puller to Remove Flywheel, NOTE: Tension spring located inside will POP” flywheel tree of crankshaft. See Figure 9-18. Figure 9-18. Spring Inside Will “POP” Flywheel Off. 3. Use needle nose pliers or side cutter to grasp and remove flywheel key. See Figure 9-19. Figure 9-19. Removing Flywheel Key From Crankshaft.Remove Stator 1. Note routing of all wiring and hamesses to reassemble in same position later. 2. Remove the two hex. flange screws securing stator to crankcase. See Figure 9-20. Figure 9-20. Removing Stator. 3, Remove the stator and let it hang loose. Remove Timing Belt 1. Remove the two hex. flange screws securing the idler pulley to the crankcase. 2. Remove idler pulley and the timing belt. See Figure 9-21 Figure 9-21. Remove Idler Pi Timing Belt. Remove Valve Covers 1. On engines with top-mounted fuel tank, remove the five 7/16” adapter studs and the five hex. flange screws securing covers. Section 9 Disassembly 2. Onall other engines remove the ten hex. flange screws securing covers. 3. Remove the dipstick. 4, Remove the valve covers and gaskets on both sides. Discard the gaskets. See Figures 9-22, 9-23, and 9-24, Figure 9-23, Removing #2 Side Valve Cover Screws. Figure 9-24. Removing Cover and Fuel Pump Assembly (#1 Side). 97Section 9 Disassembly Remove #1 Side Camshaft and Rocker Arms 1. Tum the camshaft until tension is off the rocker arms. 2. Remove the "C” clip on inside of rocker box using two small screwdrivers. 3, Remove the camshaft and thrust washer. See Figure 9-25. Figure 9-25. Removing Camshaft on #1 Side. 4, Remove the two hex. flange screws from the rocker arm shaft. See Figure 9-26. Figure 9-26. Removing Rocker Arm Shaft Screws. 5. Lift rocker arm assembly off valve mechanism, See Figure 9-27. Figure 9-27. Removing Rocker Arm Assemblies (#2 Side Shown). Remove #2 Side Camshaft and Rocker Arms 1. Tum the camshaft until tension is off the rocker arms and the colled spring pin is visible in the ‘governor body. See Figure 9-28, Figure 9-28. #2 Side Camshaft/Rocker Arm Detail. 2. Using a small punch, drive the coiled spring pin down about 5/8”. See Figure 9-29. Figure 9-29. Driving Colled Spring Pin Down. 98Section 9 Disassembly 3. Turn the camshaft 180: 4, Grasp protruding end of the coiled spring pin with vise grip pliers. Pull the pin out of camshaft. See Figure 9-30, Figure 9-30. Removing Coiled Spring Pin. 5. Hold governor halves together with one hand and slide camshaft out. See Figure 9-31 Figure 8-31. Hold Governor Together While Removing Gamshatt. 6. Lift out governor assembly. 7. Remove the two hex. flange screws from the rocker arm shatt, See Figure 9-26. 8. Lift rocker arm assembly off the valve mechanism, Remove Governor Yoke and Cross Shaft 1. Remove the two hex. socket head screws from the governor yoke. See Figure 9-32. 2. Remove the governor cross shaft. See Figure Remove Rectifier-Regulator 1. Onengines with top-mounted fuel tank, remove the wiring connector from the rectifier-regulator. 2. Remove the two mounting nuts holding the rectifier-regulator to the valley battle. Remove the rectifier-regulator and spacer. See Figure 9-33. Figure 9-33. Removing Rectifier-Regulator and Spacer. 99Section 9 Disassembly Remove Valley Baffle 1. Remove the hex. flange screw from the wire retainer on the backside of the valley battle Remove the hex. flange screw from the front side of the baffle and remove the battle, See Figure 9-34, Figure 9-34. Removing Valley Baffle. Remove Crankcase Breather 1, Remove the two hex. flange screws securing the breather cover. See Figure 9-35. Figure 9-35. Removing Crankcase Breather Cover Screws. 2. Lift off the breather cover. 3. Remove and discard the gasket. See Figure 9-36 Figure 9-36. Breather Cover Removal. 4, Remove the two hex. flange screws securing the breather housing to the crankcase. Remove the housing (there will be some resistance from the grommet underneath) 5, Remove the screw securing the breather stop and reed, See Figure 9-37. Figure 9-37. Breather Stop and Reed Removal. 6. Remove rubber grommet from bottom side of the breather. 9.10