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Tecumseh ECV100-120 - TECHNICIAN S Handbook

3 to 11 hp 4-cycle l-head engines
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TECUMSEH
This manual covers engine models:
ECV100 - 120, H22 - 80, HH40 - 70, HHM80, HM70 - 100,
HMSK70 - 110, HMXL70, HS40 - 50, HSK30 - 70, HSSK40 - 50,
HT30 - 35, HXL35, LAV30 - 50, LEV80 - 120, TNT100 - 120,
TVM125 - 220, TVXL170 - 220, TVS75 - 120, TVXL105 - 115,
V40 - 80, VH40 - 70, V60 - 70, VM70 - 100
Model numbers are located on the engine shroud.

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Summary of Contents for Tecumseh ECV100-120 - TECHNICIAN S

  • Page 1 Main Menu TECUMSEH This manual covers engine models: ECV100 - 120, H22 - 80, HH40 - 70, HHM80, HM70 - 100, HMSK70 - 110, HMXL70, HS40 - 50, HSK30 - 70, HSSK40 - 50, HT30 - 35, HXL35, LAV30 - 50, LEV80 - 120, TNT100 - 120,...
  • Page 2 Main Menu CONTENTS...
  • Page 3 Main Menu...
  • Page 4 Main Menu...

  • Page 5: Chapter 1 General Information

    Main Menu CHAPTER 1 GENERAL INFORMATION ENGINE IDENTIFICATION Tecumseh engine model, specification, and serial numbers or (date of manufacture, DOM) are stamped into the blower housing or located on a decal on the engine in locations as illustrated (diag. 1 & 2).

  • Page 6: Short Blocks

    OTHERS. FOLLOW ALL INSTRUCTIONS. FUEL Tecumseh strongly recommends the use of fresh clean unleaded regular gasoline in all engines. Unleaded gasoline burns cleaner, extends engine life and promotes better starting by reducing build-up of combustion chamber deposits. REFORMULATED AND OXYGENATED FUELS Reformulated fuels containing no more than 10% Ethanol, 15% MTBE, 15% ETBE or premium gasoline can be used if unleaded regular gasoline is not available.

  • Page 7: Engine Oil

    Main Menu ENGINE OIL Use a clean, high quality detergent oil. Be sure original container is marked: A.P.I. service SF thru SJ. The use of multigrade oil may increase oil consumption under high temperature, high load applications. NOTE: DO NOT USE SAE10W40 OIL. For summer (above 32°F, 0 C) use SAE 30 oil part # 730225 (1 quart, .946 liter container) in high temperature, high load applications.
  • Page 8 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.

  • Page 9: Chapter 2 Air Cleaners

    Dirt allowed into the engine will quickly wear the internal components and shorten the life of the engine. Tecumseh engines use either a polyurethane or a paper- COVER type air filter system. A polyurethane pre-cleaner or a flocked screen may be used in conjunction with the main filter.

  • Page 10: Disassembly Procedure

    The paper filter element should be replaced at least once a year or more frequently if operated in dusty or dirty conditions. NOTE: NEVER RUN THE ENGINE WITHOUT THE COMPLETE AIR CLEANER ASSEMBLY INSTALLED ON THE ENGINE. ALWAYS REPLACE THE FILTER ELEMENT WITH THE PROPER TECUMSEH ORIGINAL REPLACEMENT PART.

  • Page 11: Chapter 3 Carburetors And Fuel Systems

    CHAPTER 3 CARBURETORS AND FUEL SYSTEMS GENERAL INFORMATION Tecumseh uses two basic types of carburetors, float and diaphragm type carburetors. Float type carburetors use a hollow float to maintain the operating level of fuel in the carburetor. Diaphragm type carburetors use a rubber-like diaphragm.

  • Page 12: Fuel Primers

    Main Menu OPERATION In the “CHOKE” or “START” position, the choke shutter is closed and the only air entering the engine enters through openings around the shutter. As the engine starts to rotate, downward piston travel creates a low air pressure area (or vacuum) above the piston.

  • Page 13: Impulse Fuel Pumps

    This type of carburetor uses a rubber-like diaphragm which is exposed to intake manifold pressure on one side and to atmospheric pressure on the other. Tecumseh diaphragm carburetors use the diaphragm as a metering device. As the intake manifold pressure decreases due to downward...
  • Page 14 Main Menu COMPONENTS Loosen screw until it just clears CHOKE SHAFT AND LEVER Check shaft for binding. Position throttle lever, then turn screw in 1 IDLE SPEED ADJUSTMENT SCREW shutter opening towards inlet fitting turn. CHOKE SHUTTER side or air horn. THROTTLE SHAFT AND LEVER MAIN NOZZLE Place detent reference mark to...
  • Page 15 Main Menu CARBURETOR IDENTIFICATION Tecumseh has a variety of carburetors. To help identify these carburetors here are some simple procedures to follow. DUAL SYSTEM CARBURETORS The easiest way to identify the dual system carburetor is by the presence of a large primer bulb located on the side of the carburetor.

  • Page 16: Series 6 Carburetors 4-Cycle

    This carburetor also has a serviceable main nozzle emulsion tube and a stepped primer bulb to assist in starting. (diag. 20) NON-TECUMSEH CARBURETORS DELLORTO CARBURETOR The Dellorto carburetor is similar to the dual system carburetor. It has no adjustments and has a primer assist start.

  • Page 17: Engine Troubleshooting

    Main Menu ENGINE TROUBLESHOOTING Engine Will Not Start Check For Spark Check If Spark Plug Is Wet or Dry Defective Spark Plug Check Fuel Supply and Fuel Cap Vent Restricted Air Filter Restriction in Fuel System (filter, screen) Improper or Stale Fuel Carburetion Problem Sheared or Partially Sheared Poor Compression...
  • Page 18 Main Menu CARBURETION TROUBLESHOOTING...
  • Page 19 Main Menu TESTING 1. After repeated efforts to start the engine using the procedure listed in the operator’s manual fail, check for spark by removing the high tension lead and the spark plug. Install a commercially available spark plug tester and check for spark.

  • Page 20: Pre-Sets And Adjustments

    Main Menu PRE-SETS AND ADJUSTMENTS Tecumseh Carburetors Engine Model Main Pre-set Idle Pre-set (TECUMSEH AND WALBRO All models with float-type 1-1/2 turn 1 turn CARBURETORS) carburetors All models with diaphragm-type 1 turn 1 turn carburetors NOTE: OVERTIGHTENING WILL DAMAGE THE TAPER PORTION OF THE NEEDLE.
  • Page 21 Remove the retainer by prying and lifting it out with a screwdriver. Do not re-use the old bulb or retainer (diag. 30). 7. Some Tecumseh float style carburetors have a damper spring which is installed as shown. (diag. 31)
  • Page 22 "O" ring seal on the top and bottom end of the tube. Do not remove a main nozzle that is made of brass from any Tecumseh carburetor. These are pressed in at the factory to a specific depth. When removing the nozzle, the top "O"...

  • Page 23: Impulse Fuel Pump

    (diag. 37 & 38). FLOAT ADJUSTING PROCEDURE All Tecumseh carburetors with an adjustable float require the correct float height to achieve the proper operation and easy engine starts. To check the float height, hold the carburetor in an upside down position.
  • Page 24 “O” ring seal if damaged (diag. 40). Examine the tapered surface of the high speed mixture needle. If the tapered surface is damaged or shows wear, replace the needle (non-emissioned). Some Tecumseh carburetors use serviceable jet main nozzles. These are identified as being non-metallic.
  • Page 25 If binding occurs, correct by loosening screws and repositioning throttle plate. Always use a new screw(s) when reinstalling the throttle shutter (Tecumseh screws are treated with dry-type adhesive to secure them in place). NOTE: NEVER REUSE OLD SCREWS. Choke Shaft and Plate...
  • Page 26 Main Menu High and Low Speed Adjusting Screw, Main Nozzle When reassembling, position the coil spring on the adjusting screws, followed by the small brass washer and the “O” ring seal. Turn the high speed adjustment screw in approximately one turn into the bowl retainer nut to make an assembly (diag.
  • Page 27 Main Menu 4. Install the hinge pin from the opposite hinge leg. The bowl gasket must be positioned over the end of the spring (diag. 51). 5. Set the proper float height. See “Float Adjusting Procedure” in this chapter. Diaphragm Assembly The rivet head on the diaphragm must always face toward the inlet needle valve.

  • Page 28: Standard Service Carburetors

    See “Pre-sets and Adjustments” in this chapter. STANDARD SERVICE CARBURETORS Tecumseh supplies some replacement carburetors on which parts from the old carburetors can be reused or new parts added. This Standard Service Carburetor helps to reduce dealer inventories. Standard Service Carburetors are built in both float and diaphragm versions.

  • Page 29: Diaphragm Type Carburetor

    Main Menu Throttle Lever Remove the throttle lever and spring and file off the peened end of the throttle shaft until the lever can be removed. Install the throttle spring and lever on the new carburetor with the self-tapping screw furnished. If dust seals are furnished, install them under the return spring.

  • Page 30: Chapter 4 Governors And Linkage

    This chapter includes governor assembly and linkage illustrations to aid in governor or speed control assembly. Tecumseh 4 cycle engines are equipped with mechanical type governors. The governor’s function is to maintain a constant R.P.M. setting when engine loads are added or taken away. Mechanical type governors are driven off the engine’s camshaft gear.

  • Page 31: Engine Overspeeding

    Main Menu ENGINE OVERSPEEDING 1. If the engine runs wide open (faster than normal), shut the engine off immediately. 2. Check the condition of the external governor shaft, linkage, governor spring, and speed control assembly for breakage, stretching or binding. Correct or replace binding or damaged parts. 3.

  • Page 32: Governor Gear And Shaft Service

    Main Menu GOVERNOR GEAR AND SHAFT SERVICE After the cylinder cover is removed from the engine, the governor spool, gear, or governor shaft can be removed. On older style governor assemblies, the retaining ring must be removed to allow the spool or gear to slide off the shaft. Newer style governor shafts (3 - 6.75 model engines) use an upset to hold the governor spool on.

  • Page 33: Speed Controls And Linkage

    Main Menu SPEED CONTROLS AND LINKAGE Many different types of speed controls and linkage are used for O.E.M. applications. Linkage attachment points are best recorded or marked prior to disassembly. This assures the correct placement during reassembly. The solid link is always connected from the outermost hole in the governor lever to the throttle in the carburetor.
  • Page 34 Main Menu ADJUSTING RPM ON MEDIUM FRAME VERTICAL SPEED CONTROL This speed control is adjusted to the equipment throttle control by aligning the slot in the speed control lever with the alignment hole on the mounting bracket. Place a pin through the two holes, place the equipment throttle control to the wide open position, hook the bowden cable end in the control as shown, and tighten the cable housing clamp.
  • Page 35 Main Menu HORIZONTAL SHAFT ENGINES HORIZONTAL LIGHTWEIGHT LIGHTWEIGHT R.V. TYPE SMALL FRAME CONSTANT SPEED APPLICATIONS HORIZONTAL MEDIUM FRAME...
  • Page 36 Main Menu HORIZONTAL SHAFT ENGINES (CONTINUED) IDLE SPEED SCREW MAIN MIXTURE IDLE MIXTURE SCREW SCREW HMSK80-100 HORIZONTAL MEDIUM FRAME MEDIUM FRAME TO INCREASE SPEED - CLOSE LOOP TO DECREASE SPEED - SPREAD LOOP SNOW KING ENGINES SNOW KING ENGINES...
  • Page 37 Main Menu VERTICAL SHAFT ENGINES VERTICAL SHAFT ENGINES TNT 100 VERTICAL ENGINES TVS 115 ENGINE WITH "SNAP IN" SPEED CONTROL TVXL 220 WITH HORIZONTAL SPEED CONTROL STANDARD TVM ENGINE WITHOUT GOVERNOR OVERRIDE...
  • Page 38 Main Menu GOVERNOR OVERRIDE SYSTEM FOR TVM170, 195 AND 220 ENGINES This system will be found starting on 1985 production models, and will not retrofit onto older engines. It is designed to allow the governor to regulate the low and high speeds of the engine.

  • Page 39: Chapter 5 Rewind Starters

    CHAPTER 5 REWIND STARTERS GENERAL INFORMATION Rewind starters used on vertical shaft Tecumseh engines are top mount horizontal pull style or side mount vertical pull style. Horizontal shaft engines use side mounted starters which can be mounted to pull either vertically or horizontally.

  • Page 40: Retainer Replacement

    Main Menu Standard rope lengths 54" (16.5 meters) standard stamped steel starter 61" (18.6 meters) vertical pull - horizontal engagement type 65" (20 meters) vertical pull - vertical engagement type 85" (26 meters) extended handlebar rope star t (compliance) Check the old rope for the right length for the application. Some applications require longer lengths.

  • Page 41: Stylized Rewind Starter With Plastic Retainer

    Main Menu CAUTION: THIS REWIND SPRING IS NOT SECURED IN A CANISTER. PULLEY BOSSES HOLD THE REWIND SPRING AND COVER, AND CAN BE EASILY DISLODGED DURING HANDLING. 4. Remove the brake spring, spring retainer, washers, and pulley assembly (diag. 7, 8, 9 & 10) NOTE: THE STARTER DOGS FACE OUT ON THE STAMPED STEEL STARTER AND THE DOGS FACE IN ON THE STYLIZED REWIND STARTER.

  • Page 42: Standard Stamped Steel And Cast Aluminum Starter (Hm, Vm)

    Main Menu 1. If replacing the starter rope, see Step 8. Extreme caution should be used when working with springs. Always where appropriate safety equipment. 2. Install a new recoil spring if necessary by pushing the new spring out of the holder into the pulley cavity while aligning the outside spring hook into the deep notch in the pulley.

  • Page 43: Vertical Pull Starter Horizontal Engagement Type

    Main Menu 2. Place the pulley assembly into the starter housing. 3. Install the brake spring, starter dog(s), and starter dog return spring(s). The starter dog spring(s) must hold the dog(s) in against the pulley. On Snow King engines the starter dog posts should be lubricated with S.A.E.

  • Page 44: Vertical Pull Starter, Vertical Engagement Type

    Main Menu worn or damaged parts. Assembly Procedure 1. Insert the rope through the starter pulley. 2. Assemble the gear, pulley, washer, and snap ring. 3. Place a small amount of grease on the center shaft, place the gear and pulley into position making sure the brake spring loop is positioned over the metal tab on the bracket.
  • Page 45 Main Menu at the outer edge against the gear sheave. 7. Remove the retainer pin from the strut and slowly relieve the spring tension by allowing the spring capsule to rotate slowly under control, until completely unwound. The spring capsule can now be removed from the gear sheave.

  • Page 46: Chapter 6 Electrical Systems

    If a cell has an open or high resistance connection, the electric starter operation will be affected. The power source used to provide the energy to turn an electric starter motor on Tecumseh engines is either 120 volt A.C.

  • Page 47: Converting Alternating Current To Direct Current

    WIRING The wires used in Tecumseh electrical systems are copper stranded with an insulated coating around the copper strands. CONDITION: All wiring must be fully insulated between connection points, securely fastened and free of foreign material (such as rust and corrosion) at the connection points.

  • Page 48: Electrical Terms

    (20 amp system requires #14 or lower gauge number). 3. The magneto circuit wiring (ground circuit) must be rated at #18 or lower gauge number. Tecumseh's standard engine wiring color codes, effective August, 1992 are as follows: Code Product Yellow Alternator A.C.

  • Page 49: Basic Checks

    Main Menu BASIC CHECKS Before going into extensive checks, be sure to perform the more basic checks first, such as: 1. Battery defective or not charged. 2. Corroded or loose terminals and connections, or wrong connections. 3. Cracked insulation or broken wires. 4.

  • Page 50: Troubleshooting Electrical Starter Circuit Flow Chart

    Main Menu TROUBLESHOOTING ELECTRICAL STARTER CIRCUIT FLOW CHART Starter turns at Starter will not Intermittent low rpms or turn starter operation stalls under load Is there power at the power source? Repair or Is power supplied to the replace power starter terminal? source Isolate engine...

  • Page 51: Troubleshooting Electrical Charging Circuit Flow Chart

    Main Menu TROUBLESHOOTING ELECTRICAL CHARGING CIRCUIT FLOW CHART Identify the charging system used by model and specification number or visually check the electrical plug Consult Technician's Handbook Electrical Troubleshooting booklet for test procedure for the charging system used Test for either AC or DC voltage as directed at the proper engine Is the voltage greater than or equal to the minimum value?
  • Page 52 Consult a Tecumseh dealer or a parts manual to identify the charging system. To make many of the tests it is necessary to run the engine and measure alternator output with a voltmeter.
  • Page 53 Main Menu 18 Watt A.C. Lighting Alternator Models: H35, HS & HSSK 40-50, HM & HMSK 70-80-100 CHECKING THE SYSTEM: To check the system, disconnect the plug from the rest of the lighting system. Connect a wire lead from the single pin connector coming out of the engine to one terminal of a No.
  • Page 54 Main Menu TEST NO. 2 - Connect the positive probe of meter to red output lead. Connect the negative probe of meter to both A.C. terminals and black output lead. Connect the negative probe of meter to black output lead. Connect the positive probe of meter to both A.C. terminals and red output lead.
  • Page 55 Main Menu NOTE: ON OLDER POINT IGNITION SYSTEMS, THE A.C. OUTPUT LEADS ARE BLACK AND RED. 3 Amp D.C. Alternator System - Rectifier Panel This 3 amp system is readily identified by the rectifier panel in the circuit. The panel includes two diodes and a fuse for overload protection.
  • Page 56 Main Menu 3 Amp DC Alternator System - Diode in Harness Sleeve Models: H30-35, HS40, H50-60, HH50-60, GREEN HM70-80-100, HHM80 This system has a diode included in the red wire which converts the alternating current (A.C.) to direct current. The direct current (D.C.) is used to provide a trickle charge for the battery.
  • Page 57 Main Menu 5 Amp Alternator System Regulator-Rectifier Under Blower Housing INSERT PROBES INTO CONNECTOR SLOTS. DO NOT REMOVE CHECKING THE SYSTEM: An open circuit D.C. voltage CONNECTOR WIRES. check cannot be made with this system. If a known good battery fails to maintain a charge, proceed to make an A.C.
  • Page 58 Main Menu CHECKING THE SYSTEM: To check the system, disconnect the plug and measure the D.C. voltage at the red wire terminal (diag. 24). Measure the A.C. voltage at the yellow wire terminal. With the engine running, the minimum values should be: 3 Amp D.C.
  • Page 59 Main Menu 7 Amp Alternator System Regulator- Rectifier Under Engine Block Housing Models: H50-60, HH50-60, HM70-80-100, HHM80, TVM125-140-170-195-220 In this system, the regulator and rectifier are combined in one solid state unit mounted under the blower housing of the engine. Various types of regulator-rectifiers have been used on different applications.
  • Page 60 Main Menu With the engine running, minimum values should read: 2500 R.P.M. - 16.0 Volts A.C. 3000 R.P.M. - 19.0 Volts A.C. 3600 R.P.M. - 24.0 Volts A.C. A.C. If the minimum readings are noted, the alternator is okay; the regulator-rectifier is defective. If less than above readings, the alternator is defective.

  • Page 61: Volt Or 120 Volt Electric Starters With Exposed Shaft

    Main Menu SERVICE This section covers the service procedures for the 12 and 120 volt electric starters. For diagnosis of the starting circuit see “Electrical Starter Troubleshooting” in this chapter. Illustrations may not be identical in configuration to the starter being serviced, but procedures and tests apply unless otherwise stated.

  • Page 62: Inspection And Repair

    Main Menu INSPECTION AND REPAIR 1. The pinion gear parts should be checked for damage or wear. If the gear does not engage or slips, it should be washed in solvent ( rubber parts cleaned in soap and water) to remove dirt and grease, and dried before reassembly.

  • Page 63: Chapter 7 Flywheel Brake Systems

    CHAPTER 7 FLYWHEEL BRAKE SYSTEMS GENERAL INFORMATION Tecumseh’s brake systems provide two methods of meeting compliance standards which has become a federal law as of June 30, 1982. There are two additional methods used by equipment manufacturers that also meet compliance standards and they are as follows: 1.

  • Page 64: Inside Edge System

    Main Menu OPERATION (CONTINUED) INSIDE EDGE SYSTEM In the stop position the brake pad is applied to the inside edge of the flywheel, at the same time the ignition system is grounded (diag. 3). In order to restart the engine, the brake control must be applied. This action pulls the brake pad away from the inside edge of the flywheel and opens the ignition kill switch.

  • Page 65: Flywheel Removal

    Main Menu SERVICE If the brake system fails to kill the ignition and stop the blade within 3 seconds the following service procedures should be followed. FLYWHEEL REMOVAL NOTE: BEFORE THE FLYWHEEL IS REMOVED OR REPLACED, THE BRAKE PRESSURE ON THE FLYWHEEL MUST BE RELIEVED AS OUTLINED BELOW UNDER "BRAKE LEVER AND PAD".
  • Page 66 Main Menu STARTER INTERLOCK SWITCH The engine / blade control must close the interlock switch before the starter can be engaged. To check the interlock switch, use an ohmmeter or continuity light to perform a continuity check. Continuity should exist between the two terminals when the interlock switch button is completely depressed.

  • Page 67: Chapter 8 Ignition

    The Tecumseh magneto ignition consists of a stator assembly made of laminations, a coil, contact points, condenser, a permanent magnet mounted in the flywheel, high tension lead, and a spark plug. The coil is sealed by epoxy filler, and the points and condenser are sealed from dirt and moisture by a crankshaft seal and cover gasket.

  • Page 68: Identification Of Tecumseh Ignition Systems

    Main Menu IDENTIFICATION OF TECUMSEH IGNITION SYSTEMS COMPONENTS OF A TECUMSEH MAGNETO IGNITION SYSTEM (DIAG. 7) A. Flywheel with magnets B. Coil C. Condenser D. Spark plug E. Contact points Ignition cam G. Stator plate (dust cover, cam wiper, and laminations.) H.
  • Page 69 Main Menu The condenser acts as an electrical shock absorber to prevent arcing between the contact points as they open. Arcing will lower the voltage at the spark plug, as well as burn and pit the contact points. The condenser is a replaceable item (diag.

  • Page 70: Ignition Troubleshooting

    Main Menu IGNITION TROUBLESHOOTING Engine runs Engine Will erratically or shuts Not Start off, restarts Check for spark Spark No Spark Replace spark plug Check flywheel for damaged or sheared key Isolate engine and repeat test Spark Set proper air gap on No Spark external coil Engine problem, check...

  • Page 71: Testing Procedure

    8. Check the operation of the coil using an approved tester. Follow the instructions furnished with the test unit or booklets offered by the Tecumseh Products Co. Engine and Transmission Group Service Division. If the coil or lamination assembly is defective, replace as necessary.

  • Page 72: Spark Plug Service

    Main Menu SERVICE To remove ignition components from the engine, see Chapter 9 under "Disassembly". SPARK PLUG SERVICE Spark plugs should be removed, cleaned, and adjusted periodically. Check the air gap with a spark plug gap gauge and adjust accordingly. Set the spark plug gap at .030" (.762 mm) (diag.
  • Page 73 Main Menu Begin the procedure by replacing the points if necessary. To do this remove the nut that secure the movable portion of the breaker points. Remove the screw from the stationary portion of the breaker points and the worn breaker point assembly.
  • Page 74 When ordering an external coil for replacement from Tecumseh Products, a solid state module will be received as a replacement. The new module will be supplied with the proper flywheel key (diag. 28).

  • Page 75: Service Tips

    Clean points with lint free paper after setting gap. Reinstall the point terminal nut and tighten after removing leads, before timing procedure. Remember to correctly TIME a Tecumseh engine, even when just changing points on a magneto system. Remember to use correct air gap gauge.

  • Page 76: Chapter 9 Internal Engine And Cylinder

    Chapter 4. All Tecumseh engines covered in this manual are four cycle engines with the valves in the engine block. The crankshaft position is designated as either horizontal or vertical as the engine rests on its base. The engines identified by decals or model as XL (Extra Life) or XL/C (Extra Life / Commercial ) are made using aluminum alloy diecast around a cast iron cylinder liner.

  • Page 77: Lubrication Systems

    (diag. 6). On all Tecumseh vertical shaft 4-cycle engines, the oil is sprayed out under pressure through a small hole between the top camshaft and crankshaft bearing to lubricate the piston, connecting rod, and other internal parts (diag.
  • Page 78 Main Menu COMPONENTS The cylinder block houses the piston, valves and along with the cylinder cover all the internal components. The block is a one piece diecast aluminum alloy or cast iron cylinder casting (diag. 10). The piston transmits the force of the burning and expanding gases through the connecting rod to the crankshaft. The piston rings provide the seal between the cylinder wall and the piston.

  • Page 79: Engine Operation Problems

    Main Menu ENGINE OPERATION PROBLEMS ENGINE KNOCKS OVERHEATS SURGES OR RUNS UNEVENLY Associated equipment loose or Fuel cap vent obstructed Excessive engine loading improperly adjusted Check for excessive carbon in Dirty carburetor or air filter Low oil level or wrong viscosity oil combustion chamber Loose flywheel, examine key, Cooling air flow, obstructed or...
  • Page 80 Main Menu ENGINE OPERATION PROBLEMS BREATHER PASSING OIL ENGINE MISFIRES ENGINE VIBRATES EXCESSIVELY Oil level too high Wrong or fouled spark plug Bent crankshaft Excessive RPM or improper governor Carburetor improperly adjusted Attached equipment out of balance setting Damaged gaskets, seals or "O" rings Valves sticking or not seating properly Loose mounting bolts Breather damaged, dirty or improperly...

  • Page 81: Engine Overheats

    Main Menu TESTING ENGINE KNOCKS 1. Check the blade hub, blade adapter, or crankshaft coupler for loose fit, loose bolts, or crankshaft key damage. Remove, inspect, replace if necessary. Reinstall and re-torque the bolts to the proper torque. 2. Check the flywheel key and the flywheel and crankshaft keyway for wear or partial shearing. Replace if any damage is evident.
  • Page 82 Main Menu ENGINE VIBRATES EXCESSIVELY 1. Check the engine crankshaft on the PTO end for bends using a straight edge, square or a dial indicator. Blades or adapters must be removed. Any deflection will cause a vibration problem. 2. Check the engine mounting bolts, make sure they are tight. 3.
  • Page 83 Main Menu 5. Check the engine valve lash. Reset the valves at the proper lash. 6. Check the valves for proper seating and valve guide lash. Recondition the valves and seats. Replace the valves if necessary. 7. Check the ignition timing. Check the flywheel key for partial shearing. SERVICE DISASSEMBLY PROCEDURE The following procedures apply to most engine models.
  • Page 84 Main Menu 13. Remove the cylinder cover or mounting flange using a seal protector positioned in the seal to prevent seal damage. The crankshaft must be free of rust or scale to slide the cover off the crankshaft. H30-HS50 horizontal crankshaft engines with ball bearings on the crankshaft require the oil seal and the snap ring to be removed prior to the cylinder cover removal.
  • Page 85 .002 inch (.051 mm) of the desired finish size. Replace the coarse stones with finishing stones and continue honing the cylinder to the final size. Tecumseh recommends using a 390 grit hone for finishing. Clean the cylinder and crankcase with soap and water and dry thoroughly.

  • Page 86: Cylinder Heads

    Main Menu CYLINDER HEADS Check the cylinder head for warpage by placing the head on a precision flat surface. If warped in excess of .005" (.13 mm) replace the head. Slight warpage can be corrected by placing a sheet of #400 wet /dry sandpaper on a precision flat surface and rubbing the head gasket surface in a circular pattern until the entire gasket surface shows evidence of sanding.
  • Page 87 Main Menu Use a ring expander to remove and replace the rings. Do not spread the rings too wide or breakage will result. The top compression ring has an inside chamfer, this chamfer must face UP. If the second compression ring has an inside chamfer, the chamfer must face DOWN in all engines except for HM100 and TVM220 engines where the chamfer faces UP.

  • Page 88: Crankshafts And Camshafts

    Main Menu CRANKSHAFTS AND CAMSHAFTS Inspect the crankshaft visually and with a micrometer for wear, scratching, scoring, or out of round condition. Check for bends on the P.T.O. end using a straight edge, square or a dial indicator. CAUTION: NEVER TRY TO STRAIGHTEN A BENT CRANKSHAFT.
  • Page 89 Main Menu VALVES The valves should be checked for proper clearance, sealing, and wear. Valve condition is critical for proper engine performance. Valve clearance should be checked before removal from the engine block if a valve problem is suspected or when the valves or seats are recut. Valve clearance (between the valve stem and valve lifter) should be set or checked when the engine is cold.
  • Page 90 "Table of Specifications" (Chapter 10) to determine the correct oversize dimension. Reamers are available through your local Tecumseh parts supplier. Consult the tool section in Chapter 11 for the correct part numbers. The upper and lower valve spring caps must be redrilled to accommodate the oversize valve stems.

  • Page 91: Cylinder Cover, Oil Seal, And Bearing Service

    Main Menu Late production top mounted breathers use the rubber boot and breather tube as a push in design. Mark or note the location of the breather tube. Use a large flat blade screwdriver to pry the boot up and lift the breather assembly out.

  • Page 92: Crankshaft Bearing Service

    Main Menu Oil Seal Service NOTE: BEFORE REMOVING THE OIL SEAL, CHECK TO SEE IF THE SEAL IS RAISED OR RECESSED. WHEN INSTALLING A NEW OIL SEAL, TAP IT INTO POSITION GENTLY UNTIL IT IS SEATED INTO ITS BOSS. SOME SEALS ARE NOT POSITIONED FLUSH TO THE CYLINDER COVER.

  • Page 93: Counterbalance Service

    (diag. 56 & 57). FLYWHEEL SERVICE Some Tecumseh engines have polypropylene fans that are replaceable. A damaged fan can be replaced by tapping on the outside portion of the fan until it separates from the iron portion of the flywheel (diag.

  • Page 94: Engine Specifications

    Main Menu CHAPTER 10 ENGINE SPECIFICATIONS...

  • Page 95: Four Cycle Torque Specifications

    Main Menu FOUR CYCLE TORQUE SPECIFICATIONS & . n i . t f . l y s t l s t l s t l s t l . l y . l y . t x n i l n i l n i l n i l...
  • Page 96 Main Menu FOUR CYCLE TORQUE SPECIFICATIONS - CONTINUED & . n i . t f l f f l f f l f f l f f l f f l f f l f f l f f t l o n i l l i o &...

  • Page 97: Engine Specifications Standard Point Ignition

    Main Menu ENGINE SPECIFICATIONS STANDARD POINT IGNITION & & ) ³ . T . . T . t r i & t r i...
  • Page 98 Main Menu ENGINE SPECIFICATIONS STANDARD POINT IGNITION (CONT.) ) ³ . T . . T . t r i & t r i...
  • Page 99 Main Menu ENGINE SPECIFICATIONS STANDARD POINT IGNITION ) ³ . T . . T . t r i & t r i...
  • Page 100 Main Menu ENGINE SPECIFICATIONS STANDARD POINT IGNITION (Cont.) ) ³ . T . . T . t r i & t r i...

  • Page 101: Solid State And External Ignition

    Main Menu SOLID STATE AND EXTERNAL IGNITION ) ³ . T . t r i & t r i...
  • Page 102 Main Menu SOLID STATE AND EXTERNAL IGNITION & & & i l r & & & i l r ) ³ . T . t r i & t r i...
  • Page 103 Main Menu SOLID STATE AND EXTERNAL IGNITION ) ³ . T . t r i & t r i...
  • Page 104 Main Menu SOLID STATE AND EXTERNAL IGNITION & & ) ³ . T . t r i & t r i...
  • Page 105 Main Menu SOLID STATE AND EXTERNAL IGNITION (Cont.) & & ) ³ . T . t r i & t r i...

  • Page 106: Chapter 11 Educational Materials And Tools

    Tecumseh Ignition Systems. SPECIAL TOOLS BOOKLET 694862 This booklet depicts all specialty tools offered by Tecumseh which can be used on 2 and 4 cycle engines and Peerless units. QUICK REFERENCE CHART BOOKLET VIDEO PROGRAMS 695933...
  • Page 107 Main Menu FLYWHEEL KNOCK-OFF TOOL OIL SEAL DRIVER No. 670272 - Oil Seal Driver. Used with all oil seal protector-drivers to drive the seal into position. No. 670103 - Knock-off tool (right hand) (7/16"). OIL SEAL PROTECTOR / INSTALLER No. 670169 - Knock-off tool (right hand) (1/2"). Consult the specification chart or measure the shaft diameter to determine the correct tool.
  • Page 108 Main Menu 1/32" (.794 mm) OVERSIZE VALVE GUIDE REAMER VALVE LAPPING TOOL No. 670154 Valve lapping tool. REBUSHING DRIVERS No. 670283. Used on small frame 4 cycle engines on Intake and Exhaust valve guides. Oversize diameter .2807 .2817 No. 670284. Used on medium and large frame 4 cycle engines on Intake and Exhaust.

  • Page 109: Decimal/Fraction Conversions

    Main Menu DECIMAL/FRACTION CONVERSIONS .016 = 1/64 .516 = 33/64 .031 = 1/32 .531 = 17/32 .047 = 3/64 .547 = 35/64 .063 = 1/16 .563 = 9/16 .078 = 5/64 .578 = 37/64 .094 = 3/32 .594 = 19/32 .109 = 7/64 .609 = 39/64 .125 = 1/8...
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