Tecumseh 8 to 18 hp Technician / Service Manual

T E C H N I C I A N ' S H A N D B O O K TECUMSEH 8 TO 18 HP CAST IRON FOUR CYCLE ENGINES This manual covers the following models: VH80, VH100, HH80, HH100, HH120, OH120-180 Model numbers are located on the engine shroud. Other illustrated Tecumseh 2-Cycle Engine, 4-Cycle Engine and Transmission manuals; booklets; and wall charts are available through Tecumseh. For complete listing write or call

Contents Page CHAPTER 1. GENERAL INFORMATION ................................................................................................................................... 1 SECTION 1. ENGINE IDENTIFICATION ............................................................................................................................. 1 SECTION 2. ENGINE CARE ............................................................................................................................................... 2 CHAPTER 2. AIR CLEANERS, CARBURETORS, GOVERNORS AND LINKAGE ................................................................... 4 SECTION 1. AIR CLEANERS .............................................................................................................................................. 4 SECTION 2. GENERAL CARBURETOR INFORMATION .................................................................................................. 5 SECTION 3. TECUMSEH CARBURETORS ....................................................................................................................... 6 SECTION 4. WALBRO CARBURETORS .......................................................................................................................... 10 HH80 - 120, VH80 - 100 .............................................................................................................................................. 10 SECTION 5. OVERHEAD VALVE ENGINE CARBURETORS .......................................................................................... 13 SECTION 6. GOVERNORS ............................................................................................................................................... 16 SECTION 7. IMPULSE FUEL PUMP ................................................................................................................................. 19 CHAPTER 3. REWIND STARTERS, ELECTRIC STARTERS, TROUBLESHOOTING AND GENERATORS ......................... 20 SECTION 1. REWIND STARTERS .................................................................................................................................... 20 SECTION 2. ELECTRIC STARTERS ................................................................................................................................ 22 SECTION 3. 12 VOLT STARTER TROUBLE SHOOTING CHART ................................................................................... 25 CHAPTER 4. GENERAL VALVE INFORMATION, CYLINDER HEAD AND BREATHER ASSEMBLY ................................... 27 SECTION 1. GENERAL VALVE INFORMATION ............................................................................................................... 27 SECTION 2. CYLINDER HEAD ......................................................................................................................................... 31 SECTION 3. BREATHER ASSEMBLIES ........................................................................................................................... 32 CHAPTER 5. PISTON AND RINGS, CONNECTING RODS AND CRANKSHAFTS ................................................................ 33 SECTION 1. PISTON AND RINGS .................................................................................................................................... 33 SECTION 2. CONNECTING RODS ................................................................................................................................... 35 SECTION 3. CRANKSHAFTS ........................................................................................................................................... 36 CHAPTER 6. CAMSHAFT, BEARINGS AND SEALS ............................................................................................................... 37 SECTION 1. CAMSHAFT .................................................................................................................................................. 37 SECTION 2. BEARINGS .................................................................................................................................................... 38 SECTION 3. SEALS ........................................................................................................................................................... 42 CHAPTER 7. DYNA-STATIC ® BALANCING SYSTEM ............................................................................................................. 43 CHAPTER 8. IGNITION SYSTEMS, CHARGING SYSTEMS BATTERY SERVICE and ELECTRICAL CONTROL PANELS .......................................................................................................................................... 45 SECTION 1. IGNITION SYSTEMS .................................................................................................................................... 45 SECTION 2. CHARGING SYSTEMS ................................................................................................................................. 48 SECTION 3. BATTERY SERVICE ..................................................................................................................................... 53 SECTION 4. ELECTRICAL CONTROL PANELS .............................................................................................................. 56 CHAPTER 9. TROUBLESHOOTING ........................................................................................................................................ 61 CHAPTER 10. 8 H.P. & LARGER ENGINE SPECIFICATIONS AND TORQUES .................................................................... 66 SECTION 1. CROSS REFERENCE LIST FOR TABLE OF SPECIFICATIONS ................................................................ 66 SECTION 2. TORQUE SPECIFICATIONS ........................................................................................................................ 70 8 H.P. & LARGER ENGINES (EXCEPT VALVE-IN-HEAD) ......................................................................................... 70 SECTION 3. VALVE-IN-HEAD ENGINE SPECIFICATIONS ............................................................................................. 71 SECTION 4. TORQUE SPECIFICATIONS ........................................................................................................................ 73 VALVE-IN-HEAD .......................................................................................................................................................... 73 CHAPTER 11. EDUCATIONAL MATERIALS AND TOOLS ...................................................................................................... 74 i C Tecumseh Products Company 1998

1 CHAPTER 1. GENERAL INFORMATION SECTION 1. ENGINE IDENTIFICATION Tecumseh engine model numbers are stamped into the blower housing, or are located on a nameplate or tag on the engine in locations as illustrated. INTERPRETATION OF MODEL NUMBER. The first letter designations in a model number indicate the basic type of engine. HH - Horizontal-Heavy Duty (Cast Iron) VH - Vertical-Heavy Duty (Cast Iron) OH - Overhead Valve-Heavy Duty (Cast Iron) The number designations following the letter indicates the horsepower of the engine. The number following the model number is the specification number. The last three numbers of the specification number indicate a variation to the basic engine specification. The serial number indicates the production data. Using model number OH160-170033, Serial 8044C as an example, interpretation is as follows: OH160-170033 - is the model and specification number. OH - Overhead Valve-Heavy Duty (Cast Iron) 160 - Indicates 16 horsepower. 170033 - is the specification number used for properly identifying the parts of the engine. 8044C - is the serial number. 8 - first digit is the year of manufacture (1998) 044 - indicates calendar day of that year (044 day or February 13, 1998). C - represents the line, shift or plant in which the engine was built at the factory. SHORT BLOCKS. New short blocks are identified by a tag marked SBH (Short Block Horizontal) or SBV (Short Block Vertical). Original model tags of engines should always be transferred to a short block for correct parts identification. OH160-170033 SER 8044C

2 SECTION 2. ENGINE CARE FUELS. Use clean, fresh unleaded automotive gasoline in all Tecumseh four-cycle engines. (Leaded “regular” gasoline is an acceptable substitute.) NOTE: Do Not use gasoline containing methanol (wood alcohol). Gasoline containing a maximum of 10 ethanol or grain alcohol (sometimes called “gasohol”) may be used but requires special care when engine is unused for extended periods. See “STORAGE” instructions. ENGINE OIL, ALL FOUR CYCLE ENGINES: USE A CLEAN, HIGH QUALITY, DETERGENT OIL. Be sure original container is marked with engine service classification “SF - SJ.” DO NOT USE SAE10W40 OIL. FOR SUMMER (ABOVE 32°F, 0°C) USE SAE 30 OIL (SAE10W30 is an acceptable substitute.) FOR WINTER (BELOW 32°F, 0°C) USE SAE 5W20 OR 5W30 OIL. (SAE10W is an acceptable substitute.) (BELOW 0°F, -18°C ONLY) Use 0W30 oil or SAE10W oil diluted with 10% kerosene is acceptable. NOTE: For severe, prolonged, winter operation of HH120 model, SAE10W oil is recommended. OIL CHANGE INTERVALS. Change oil after first two (2) hours of operation and every 25 hours thereafter, or more often if operated under dusty or dirty conditions. OIL CHECK. Check oil every 5 hours or each time the equipment is used. Position equipment so the engine is level when checking the oil. BREAK-IN PROCEDURE. Proper break-in procedure is important for proper seating of rings, on a new engine or newly overhauled engine. Do normal work with the unit, running the engine under load. Vary the load on the engine frequently to aid in seating of the rings. The engine should not be allowed to idle or run at part throttle for extended periods during break-in. Work the engine but do not abuse it. TUNE-UP PROCEDURE. The following is a minor tune-up procedure. When this procedure is completed, the engine will operate properly or you may discover that further repairs may have to be performed. NOTE: It is recommended to use only factory parts in a Tecumseh engine. This is especially important with an air filter, since the use of any other than the specified part number may result in serious damage to the engine. CAUTION: Remove spark plug wire before doing any service work on engine. 1. Service or replace air cleaner as necessary. 2. Inspect level and condition of oil; drain oil. 3. Remove blower housing, clean all dirt, grass or debris from intake screen, head and cylinder cooling fins and carburetor governor levers and linkage. 4. Remove cylinder head, remove carbon, inspect valves and cylinder bore. Replace head using a new head gasket. Torque to specifications. 5. Remove carburetor, clean and install carburetor kit, make adjustment pre-sets where needed. Make sure fuel tank, fuel filters and fuel lines are clean. Reinstall carburetor, replacing any worn or damaged governor springs or linkage. Make proper governor adjustment. 6. Remove flywheel, check for leaks in oil seals, check flywheel key and reinstall flywheel. Replace spark plug and check for spark. 7. Make sure all remote linkage is properly adjusted for proper operation. 8. Replace fuel and oil. 9. Run engine and adjust carburetor and set R.P.M. to specifications found on Microfiche or computer parts lookup. STORAGE: (IF THE ENGINE IS TO BE UNUSED FOR 30 DAYS OR MORE) CAUTION: NEVER STORE THE ENGINE WITH FUEL IN THE TANK INDOORS , IN ENCLOSED POORLY VENTILATED AREAS WHERE FUEL FUMES MAY REACH AN OPEN FLAME, SPARK OR PILOT LIGHT AS ON A FURNACE, WATER HEATER, CLOTHES DRYER OR OTHER GAS APPLIANCE. Gasoline can become unstable in less than 30 days and form deposits that can impede proper fuel flow and engine operation. To prevent deposits from forming, all gasoline must be removed from the fuel tank and the carburetor. An acceptable alternative to removing all gasoline is adding a fuel stabilizer to the gasoline. Fuel stabilizer (such as Tecumseh’s Part No. 730245) is added to the fuel tank or storage container. Always follow the mix ratio found on the stabilizer container. Run the engine at least 10 minutes after adding the stabilizer to allow it to reach the carburetor.

3 DRAINING THE FUEL SYSTEM: CAUTION: DRAIN THE FUEL INTO AN APPROVED CONTAINER OUTDOORS, AND AWAY FROM ANY OPEN FLAME OR COMBUSTION SOURCE. BE SURE THE ENGINE IS COOL. 1. Remove all gasoline from the fuel tank by running the engine until the engine stops, or by draining the fuel tank by removing the fuel line at the carburetor or fuel tank. Be careful not to damage the fuel line, fittings, or fuel tank. 2. Drain the carburetor by pressing upward on the bowl drain (if equipped) which is located on the bottom of the carburetor bowl. On carburetors without a bowl drain, the carburetor may be drained by loosening the bowl nut on the bottom carburetor one full turn. Allow to completely drain and retighten the bowl nut being careful not to damage the bowl gasket when tightening. 3. If "Gasohol" has been used, complete the above procedure and then put one half pint of unleaded gasoline into the fuel tank and repeat the above procedure. If Gasohol is allowed to remain in the fuel system during storage, the alcohol content will cause rubber gaskets and seals to deteriorate. Change Oil: If the oil has not been changed recently, this is a good time to do it. Oil Cylinder Bore: 1. Disconnect the spark plug wire and ground the wire to the engine. Remove the spark plug and put 1/2 ounce (14 ml) of clean engine oil into the spark plug hole. 2. Cover the spark plug hole with a shop towel. 3. Crank the engine over slowly several times. CAUTION: AVOID SPRAY FROM SPARK PLUG HOLE WHEN SLOWLY CRANKING ENGINE OVER. 4. Install the spark plug and connect the spark plug wire. Clean Engine: Remove the blower housing and clean all dirt, grass or debris from the intake screen, cylinder head, cylinder cooling fins, carburetor, governor levers and linkage.

4 CHAPTER 2. AIR CLEANERS, CARBURETORS, GOVERNORS AND LINKAGE SECTION 1. AIR CLEANERS PAPER-TYPE AIR CLEANER SERVICE. Dry type paper air cleaners are utilized on all Tecumseh Large Frame engines. These air cleaners have treated paper elements with rubberlike sealing edges. These edges must seal properly to prevent dirt leakage. PAPER-TYPE AIR CLEANER SERVICE. Replace air filter once a year or more often in extremely dusty or dirty conditions. DO NOT ATTEMPT TO CLEAN OR OIL FILTER. Be sure to clean base and cover thoroughly before installing new paper filter. NEVER RUN THE ENGINE WITHOUT THE COMPLETE AIR CLEANER INSTALLED ON THE ENGINE. NOTE: Serious damage to the engine may result in using other than the specified part number filter. Use factory recommended parts only. POLYURETHANE-TYPE AIR CLEANER. Some Tecumseh Large Frame engines may use a polyurethane air filter in conjunction with a paper filter. POLY-TYPE AIR CLEANER SERVICE. Clean and re-oil every 3 months or every 25 operating hours, whichever comes first. Clean daily if used in extremely dusty or dirty conditions. Proceed as follows: Remove wing nut and cover. Slide foam filter off paper filter. Wash foam filter in water and detergent solution and squeeze, Don’t twist until all dirt is removed. Rinse thoroughly in clear water. Wrap in a clean cloth and squeeze, Don’t twist until completely dry. Saturate foam filter with engine oil and squeeze, Don’t twist to distribute oil and remove excess oil. Clean top side of base and inside of cover thoroughly. Replace foam filter, cover and wing nut. Tighten wing nut securely. NEVER RUN ENGINE WITHOUT COMPLETE AIR CLEANER INSTALLED ON ENGINE. COVER ELEMENT BASE SEALING EDGES GASKET BOLT SPACER BRACKET BOLT BACK COVER PAPER ELEMENT POLY OUTER ELEMENT FRONT COVER

5 SECTION 2. GENERAL CARBURETOR INFORMATION CARBURETOR IDENTIFICATION . Tecumseh carburetors are identified by a model number and code date stamping on the carburetor as illustrated. When servicing carburetors, use the engine model number or the model number on the carburetor and proper section in the Master Parts Manual or Microfiche Catalog for proper service information. These carburetors are used on some HH80-100- 120 and VH80-100 engines. This carburetor is used on the Overhead Valve engine 12, 14, 16 & 18 horsepower. FLOAT-FEED CARBURETORS. Float-feed carburetors use a hollow metal float to maintain the operating level of fuel in the carburetor. As the fuel is used, the fuel level in the carburetor bowl drops and the float moves downward. This actuates the inlet needle valve, to allow fuel to flow by gravity into the fuel bowl. As the fuel level in the bowl again rises, it raises the float. This float motion adjusts the fuel flow at the proper rate and keeps the fuel at the proper mixture level. CARBURETOR CODE DATE CARBURETOR MODEL NUMBER ALTERNATE LOCATION FOR MODEL NUMBER 89 3 F 5 89 3 F CARBURETOR MODEL NUMBER

6 SECTION 3. TECUMSEH CARBURETORS Following are initial carburetor adjustments to be used to start the engine. After the engine has reached operating temperature make final adjustments. Main Adjustment HH80-100-120 Screw VH100, 1-3/4 turns. Idle Adjustment HH80-100-120 Screw VH100, 1-1/4 turns The Master Parts Manual or Microfiche has a direct engine-to carburetor reference list. Further identification of the carburetor is stamped on the carburetor body as shown. Refer to the standard service part number and the identification number on the carburetor body, in any correspondence. CARBURETOR DISASSEMBLY, INSPECTION AND ASSEMBLY. Carefully disassemble carburetor, removing all non-metallic parts, i.e., gaskets, viton seats and needles, “O” rings, fuel pump valve, etc. THROTTLE. Examine the throttle lever shaft and shutter prior to disassembly. Replace any worn parts. 1. Remove the screw in the center of the throttle shutter and pull out the throttle shaft lever assembly. 2. When reassembling, replace the throttle shutter with identifying marks as positioned prior to disassembly. The throttle shaft must be held in tight to the bottom bearing to prevent the throttle shutter from riding on the throttle bore of the body, causing excessive throttle shutter wear and governor hunting. CHOKE. Examine the choke lever, shaft and shutter prior to disassembly. Replace any worn parts. 1. Remove the screw in the center of the choke shutter and pull out the choke shaft lever assembly. 2. When reassembling, replace the choke shutter with identifying marks as positioned prior to disassembly. Hold the choke shaft securely into the bearing bore when replacing the choke shutter. IDLE ADJUSTMENT SCREW. Remove the idle screw from the carburetor body and examine the point for damage to the seating surface of the taper. Replace any damaged parts. CARBURETOR MODEL NUMBER WELCH PLUG CHOKE LEVER THROTTLE LEVER NOTE: IDENTIFYING MARK WILL BE FOUND IN THE 3 O’CLOCK POSITION THROTTLE SHUTTER CHOKE SHUTTER CUT OUT CLEARANCE FOR INTERNAL VENT TUBE GOOD BAD

7 HIGH SPEED ADJUSTMENT SCREW. For service, examine the taper of the high speed adjustment screw. If the taper is damaged at the area where it seats, replace the screw and fuel bowl retainer nut as an assembly. FUEL BOWL RETAINING NUT. Remove the fuel bowl retaining nut including fiber washer. Examine the small fuel passage in the annular groove in the retaining nut. This passage must be clean for the proper transfer of fuel into the idle metering system. Replace any worn parts. When replacing, torque the fuel bowl nut to 50-60 inch pounds. INLET NEEDLE. The inlet needle is anchored to the float tab by a clip, to assure proper movement of the inlet needle off of the seat when the float drops. The inlet needle clip must be positioned as shown during reassembly. FUEL BOWL. Check the bowl for corrosion or dirt. Replace if necessary. The fuel bowl must be free of dirt and corrosion. When tearing down carburetor for repair, replace fuel bowl “O” ring. Before installation lubricate the “O” ring with a small amount of oil for easier installation. The fuel bowl flat surface must be positioned on the same side of the carburetor as the fuel inlet fitting or same side as the float hinge pin to assure full travel of the float. FLOAT. Remove the float. Examine the float for crushing or holes. Examine the float hinge bearing surfaces through which the float hinge pin passes and replace if worn. Examine the inlet needle. If any wear is evident, or any of the corners show signs of rounding, the needle should be replaced. The inlet needle hooks onto the float tab by means of a spring clip. To prevent binding, the long, straight end of the clip should face the choke end of the carburetor as shown. SERVICING THE VITON SEAT. a. REMOVAL. If the seat is to be replaced use the bent end of a paper clip or wire with a 3/32'’ (.24 mm) hook. Push the hook through the Viton seat hole. Then with the hook, pull the Viton seat out. Replace with a new seat. NOTE: A #4 crochet hook can also be used for removal. b. INSTALLATION. NOTE: After thoroughly cleaning the cavity, moisten the viton seat with oil. Insert the seat with the grooved side into the cup. Press the viton seat squarely into the base with a punch. FUEL BOWL FLAT OF FUEL BOWL TOWARD FUEL INLET FITTING FIBER WASHER FUEL BOWL RETAINING NUT “O” RING BRASS WASHER HIGH SPEED ADJUSTMENT SPRING AND SCREW TORQUE TO 50 - 60 INCH POUNDS “O” RING FUEL BOWL CHECK FOR CORROSION AND DIRT CLIP LONG END OF CLIP OPEN END OF CLIP THROTTLE END CHOKE END 3/32” (.24 mm) INLET NEEDLE SEATS AT THIS POINT INSERT THIS FACE FIRST REMOVAL OF VITON SEAT INSTALLATION OF VITON SEAT HOOK END

8 HIGH SPEED NOZZLE. The carburetor body contains a main nozzle emulsion tube pressed into the carburetor body to a predetermined depth and positioned within the venturi of the carburetor. Do not attempt to remove this main nozzle. Repositioning of this nozzle will seriously affect the metering characteristics of the carburetor and will require replacement of the entire carburetor. FUEL INLET FITTING. If necessary, this fitting can be removed by pulling and twisting. Be sure to install the fitting in the same position as the original. When installing the fitting, insert tip into the carburetor body, then coat the exposed portion of the shank with Loctite grade A; then press it in until the shoulder contacts the carburetor body. CARBURETOR BODY. When removing the choke and throttle shafts, check shafts and bearings in carburetor body for wear. Any looseness in these areas can cause dirt to enter the engine and cause premature wear. If dust seals are present, these should be positioned next to the carburetor body. To do a proper cleaning job, welch plugs should be removed to expose drilled passages. To remove the welch plug, sharpen a small chisel to a sharp wedge point. Drive the chisel into the welch plug, push down on chisel and pry plug out of position. When all accessories and shafts have been removed, soak the carburetor in carburetor cleaner for a maximum of 30 minutes. Blow out all passages with compressed air in the opposite direction of normal fuel flow or use a soft tag wire. Clean all metallic parts with solvent. To install a new welch plug after cleaning, place the welch plug into receptacle with raised portion up. With a punch equal, or greater than the size of the plug, merely flatten the plug. Do not dent or drive the center of the plug below the top surface of the carburetor. WELCH PLUG MAIN NOZZLE EMULSION TUBE DO NOT REMOVE PRESS IN PARTIALLY THEN APPLY LOCTITE GRADE A SOME INLET FITTINGS UTILIZED A STRAINER SMALL CHISEL PRY OUT PLUG PIERCE PLUG WITH TIP WELCH PLUG TO BE REMOVED DO NOT ALLOW CHISEL POINT TO STRIKE CARBURETOR BODY ABOUT 1/8” (3.2 MM) WIDE SMALL CHISEL FLAT-END PUNCH NEW WELCH PLUG SAME OR LARGER DIAMETER OF PLUG

Tecumseh 8 to 18 hp Technician / Service Manual

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