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Tecumseh OHH50 - 65 Handbook

4-cycle overhead valve engines
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See also: Technician's Handbook
TECUMSEH
T E C H N I C I A N ' S
H A N D B O O K
This manual covers engine models:
OHH50 - 65, OHHSK50 - 130, OHV11 - OHV17, OVM120,
OVRM40-675, OVRM120, OVXL/C120, OVXL120, OVXL125.
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
CONTAINS SEARS CRAFTSMAN CROSS REFERENCE
4-CYCLE
OVERHEAD
VALVE
ENGINES

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  • Page 1 T E C H N I C I A N ' S H A N D B O O K This manual covers engine models: OHH50 - 65, OHHSK50 - 130, OHV11 - OHV17, OVM120, OVRM40-675, OVRM120, OVXL/C120, OVXL120, OVXL125. Other illustrated Tecumseh 2-Cycle Engine, 4-Cycle Engine and Transmission manuals;...
  • Page 2 CONTENTS CHAPTER 1 GENERAL INFORMATION ....... CHAPTER 4 GOVERNORS AND LINKAGE ....CHAPTER 2 AIR CLEANERS ........CHAPTER 5 RECOIL STARTERS ......... CHAPTER 3 CARBURETORS AND FUEL SYSTEMS . CHAPTER 6 ELECTRICAL SYSTEMS ......
  • Page 3 All rights reserved. No part of this book may be reproduced or transmitted, in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without permission in writing from Tecumseh Products Company Training Department Manager.

  • Page 4: Engine Identification

    CHAPTER 1 GENERAL INFORMATION THIS ENGINE MEETS 1995-1998 CALIF. EMISSION REGULATIONS FOR ULGE ENGINES AS APPLICABLE FUEL: REGULAR UNLEADED OIL : USE SAE 30 OHV 125 203000A RTP358UIG2RA 358cc 3057D...

  • Page 5: Fuels/Oil

    * NOTE: Model OHSK110 with a spec. of 221000 and up, have a capacity of 26 oz. (720 ml.)
  • Page 11 ALTERNATE LOCATION FOR MANUFACTURING NUMBER CARBURETOR MANUFACTURING DATE CODE NUMBER CHOKE PLATE FLAT DOWN...
  • Page 12 TYGON TUBE EXTERNAL VENT INTERNAL VENT PRIMER BULB PRIMER BULB VENT MAIN NOZZLE MAIN JET CARBURETOR FITTING VALVE CLOSED VALVE OPEN ATMOSPHERIC DIAPHRAGM VENT FILTER AIR BLEED VALVE CLOSED VALVE OPEN FUEL SUPPLY PULSE LINE TO CRANKCASE SUCTION FUEL FLOW DIRECTION CRANKCASE PRESSURE CRANKCASE SUCTION AND ATMOSPHERIC PRESSURE...
  • Page 14 CAPPED FIXED IDLE JET MIXING WELL CAST BUT NOT MACHINED IDLE JET CAST BUT NOT MACHINED LOW IDLE MIXTURE SCREW MAY BE ADJUSTABLE OR FIXED...
  • Page 16 SERIES "7" SERIES "3" & "4" MAIN MIXTURE IDLE MIXTURE SCREW SCREW SERIES "8" SERIES "9" SERIES "10" WALBRO LMK CAPPED FIXED IDLE JET...
  • Page 17 CLIP LONG END OPEN END OF CLIP OF CLIP THROTTLE CHOKE...
  • Page 18 WALBRO LMK SERIES SMALL ATMOSPHERIC PIERCE PLUG CHISEL BRASS OR BALL PLUG VENT WITH TIP PRY OUT WELCH PLUG TO PLUG BE REMOVED DO NOT ALLOW CHISEL POINT ABOUT 1/8" TO STRIKE (3.175 mm) CARBURETOR WIDE BODY OR BALL PLUG IDLE FUEL PASSAGE CHANNEL SMALL CHISEL REDUCTION ROD INSIDE...
  • Page 19 FLOAT FLOAT HINGE AND AXLE FLOAT SETTING 11 / 64" (4.36 mm) ADJUSTING TAB INLET NEEDLE AND SEAT "O" RING RETAINER NUT BRASS WASHER SPRING HIGH SPEED ADJUSTMENT SCREW IDLE FUEL FUEL- TRANSFER FUEL- INLET PASSAGE METERING PORT ONE-HOLE TYPE TW0-HOLE TYPE...
  • Page 20 FLOAT HINGE SEAT NEEDLE FLOAT NEEDLE & SPRING CLIP SEAT MAIN NOZZLE HINGE PIN EMULSION SEAT RETAINING "O" RING "O" RING RING POSITIONED IN GROOVE NOZZLE SPRING IDLE RESTRICTION "O" RING BOWL POSITIONED IN GROOVE 'O' RING MAIN JET BOWL MAIN JET SPRING WASHER...
  • Page 21 FLAT END PUNCH NEW WELCH PLUG SAME OR LARGER DIAMETER OF PLUG HOLE THROTTLE THROTTLE PLATE LEVER On Walbro LMK and Series 7 carburetors, install the DUST SEALS throttle return spring on the throttle shaft with the squared end up. Slide the foam dust seal over the spring.
  • Page 22 CHOKE PLATE FLAT DOWN SPRING HOOKUPS PRESS IN PARTIALLY SOME INLET FITTINGS THEN APPLY LOCTITE STRAINER "O" RING RETAINER NUT BRASS WASHER SPRING HIGH SPEED ADJUSTMENT SCREW FLOAT HINGE PIN FLOAT NEEDLE & SEAT MAIN NOZZLE EMULSION SEAT RETAINING RING "O"...
  • Page 23 PUSH IN UNTIL SEAT RESTS ON BODY SHOULDER 5/32" (3.969 mm) FLAT PUNCH IF YOUR CARBURETOR SEAT HAS A STEEL SEAT RETAINING RING RE-INTSALL AFTER SEAT INSTALLATION INSERT THIS FACE FIRST INLET NEEDLE SEATS AT THIS POINT CLIP LONG END OPEN END OF CLIP OF CLIP Points toward choke...
  • Page 24 CARBURETOR FITTING VALVE CLOSED VALVE OPEN ATMOSPHERIC DIAPHRAGM VENT FILTER AIR BLEED VALVE CLOSED VALVE OPEN PULSE LINE FUEL SUPPLY TO CRANKCASE SUCTION FUEL FLOW DIRECTION CRANKCASE PRESSURE CRANKCASE SUCTION AND ATMOSPHERIC PRESSURE FLOW DIRECTION ATMOSPHERIC PRESSURE ACTING ATMOSPHERIC PRESSURE CAUSED FUEL FLOW ON DAMPING DIAPHRAGM FUEL FLOW...
  • Page 25 SPRING THROTTLE GOVERNOR SHAFT GOVERNOR WEIGHTS SPOOL GOVERNOR GEAR...
  • Page 26 THROTTLE OPEN PUSH (PUSH COUNTERCLOCKWISE) LEVER TO WIDE OPEN STANDARD THROTTLE LOCATION GOVERNOR GOVERNOR LEVER CLAMP GOVERNOR SCREW SCREW GOVERNOR GOVERNOR CLAMP TURN CLIP COUNTERCLOCKWISE ON ALL VERTICAL ROTATE CLAMP COUNTERCLOCKWISE SHAFT ENGINES EXCEPT VLV & VLXL. CLOCKWISE ON ALL HORIZONTAL SHAFT ENGINES EXCEPT OHH,OHSK 50,55 &...
  • Page 27 SERVICED AS ASSEMBLY RETAINING RETAINING RING RING SPOOL SPOOL SPOOL SPOOL SPOOL WASHER UPSET WASHER RETAINING RETAINING RING RETAINING RING RING SHAFT GEAR ASSY. GEAR ASSY. GEAR ASSY. SHAFT (GOV.) (GOV.) (GOV.) WASHER GEAR ASSY. WASHER (GOV.) WASHER SPACER GEAR ASSY. SPACER NOTE;...
  • Page 28 HIGH SPEED STOP...
  • Page 29 WINTER APPLICATION CONTROL GOVERNED IDLE LINK ADJUSTMENT HIGH SPEED HIGH SPEED ADJUST ADJUSTMENT BEND TO ADJUST SPEED DECREASE INCREASE OHH REMOTE & MANUAL OHH FIXED SPEED THROTTLE CRACK SCREW T-10 GOVERNED HIGH SPEED ADJUST BEND INCREASE DECREASE CORRECT BUSHING INSTALLATION DEEP GOVERNOR SPRING SIDE GOVERNED IDLE LINK...
  • Page 30 HIGH SPEED ADJUST GOVERNED IDLE ADJUST OHV11 - 17 SPEED CONTROL OVM / OVXL GOVERNOR OVERRIDE...
  • Page 31 OHV VERTICAL CONTROL OHV 11 - 17 HORIZONTAL CONTROL...
  • Page 32 ROPE STARTER HOUSING HANDLE PULLEY AND REWIND SPRING ASSY. STARTER DOG DOG SPRING WASHER RETAINER BRAKE SPRING WASHER SPRING PIN...
  • Page 33 STAPLE ONE PIECE ROPE RETAINER ROPE STARTER HOUSING HANDLE PULLEY AND REWIND SPRING ASSY. STARTER DOG DOG SPRING WASHER RETAINER LEFT-HAND BRAKE SPRING KNOT WASHER SPRING PIN...
  • Page 34 STARTER HOUSING HANDLE HANDLE INSERT ROPE PULLEY AND REWIND SPRING ASSY. SPRING WASHER STARTER DOG RETAINER BRAKE SPRING WASHER SPRING PIN STARTER HOUSING HANDLE ROPE PULLEY AND REWIND SPRING ASSY. DOG SPRING STARTER DOG WASHER RETAINER LEFT-HAND KNOT BRAKE SPRING WASHER SPRING PIN RETAINER WEDGE...
  • Page 35 STARTER HOUSING STARTER PULLEY SPRING & COVER DOG SPRING STARTER DOG DOG RETAINER STARTER HOUSING REWIND HANDLE SPRING AND KEEPER ASSY. ROPE HANDLE INSERT DOG SPRING PULLEY STARTER DOG DOG RETAINER LEFT-HAND RETAINER SCREW KNOT CAM DOG BRAKE SPRING WASHER SPRING PIN "STAMPED STEEL WITH ROLL PIN"...
  • Page 36 HOUSING HANDLE SPRING & KEEPER ASSY. PULLEY BRAKE SPRING DOG SPRNG RETAINER RETAINER SCREW CENTER PIN "STAMPED STEEL" STARTER HOUSING REWIND HANDLE SPRING AND KEEPER ASSY. ROPE HANDLE INSERT DOG SPRING PULLEY STARTER DOG DOG RETAINER LEFT-HAND RETAINER SCREW KNOT CAM DOG BRAKE SPRING WASHER...
  • Page 37 STARTER HOUSING REWIND SPRING PULLEY BRAKE SPRING STARTER DOGS STARTER DOG SPRING LEFT-HAND STARTER DOG RETAINER KNOT WASHER LOCKWASHER 6mm METRIC NUT TYPE I STARTER HOUSING SPRING AND KEEPER PULLEY STARTER DOG RETAINER SPRING WASHER STARTER DOG STARTER DOG RETAINER BRAKE SPRING CENTER SCREW LOCKWASHER...
  • Page 38 BOLT END CAP BRUSHES WASHER BRUSH SPRINGS NUTS BRUSH CARD HOUSING ARMATURE SPRING RETAINER END CAP RETAINER ENGAGING NUT GEAR SPRING ROTATION OF FLYWHEEL...
  • Page 39 CATHODE ANODE BAND OR OTHER MARKING INDICATES CATHODE END HALF WAVE RECTIFIER + VOLTAGE (SINGLE DIODE) + VOLTAGE A.C. INPUT D.C. OUTPUT - VOLTAGE - VOLTAGE FULL WAVE RECTIFIER (BRIDGE RECTIFIER) + VOLTAGE - VOLTAGE A.C. INPUT A.C. INPUT + VOLTAGE (D.C.) + VOLTAGE D.C.
  • Page 40 THE LARGER THE NUMBER THE SMALLER THE WIRE # 18...
  • Page 43 CAUTION: FOLLOW ALL SAFETY PRECAUTIONS WHEN TESTING FOR A.C. VOLTAGE, ELECTRIC SHOCK CAN KILL.
  • Page 44 ENGINE YELLOW #4414 BULB YELLOW YELLOW A.C. GREEN IGNITION STOP YELLOW TWO DIODES D.C. D.C. NEGATIVE OUTPUT LEAD (BROWN D.C.) D.C. POSITIVE OUTPUT LEAD (RED D.C.) D.C. A.C.
  • Page 45 DIODE GREEN D.C. SOLDERLESS SPADE CONNECTOR CONNECTOR FUSE HOLDER IF BULB DOES NOT LIGHT OR LIGHTS WHEN POLARITY REVERSED, DISCARD DIODE.
  • Page 46 INSERT PROBES INTO CONNECTOR SLOTS. DO NOT REMOVE CONNECTOR WIRES. YELLOW NOTE: D.C. OUTPUT MUST BE DISCONNECTED TO PERFORM A.C. OUTPUT TEST. A.C. VOLTMETER CAUTION: BLOWER HOUSING MUST BE INSTALLED WHEN RUNNING ENGINE RED LEAD DIODE 3 AMP D.C. BLACK LEAD 5 AMP A.C.
  • Page 47 DIODE YELLOW D.C. DIODE YELLOW A.C. DIODE A.C.
  • Page 48 A.C. INSERT PROBES INTO CONNECTOR SLOTS DO NOT REMOVE CONNECTOR WIRES YELLOW CAUTION: BLOWER HOUSING MUST BE INSTALLED WHEN RUNNING ENGINE A.C. VOLTMETER...
  • Page 49 A.C. OUTPUT YELLOW D.C. OUTPUT - RED SOLENOID LIGHT SWITCH GREEN MAGNETO GROUND FUSE BATTERY AMMETER REGULATED D.C. OUTPUT YELLOW NOTE: D.C. OUTPUT MUST BE DISCONNECTED TO PERFORM A.C. OUTPUT TEST. DOUBLE SINGLE...
  • Page 50 FLOAT SWITCH If equipped, the indicator light will flash if the oil level is at or below the add mark and the engine is turned over while attempting to start. Test by turning the engine over with the oil level below the add mark. If the LIGHTED ENGINE ON/OFF ROCKER SWITCH indicator light does not flash, replace the indicator light.
  • Page 51 BRUSHES GASKET ARMATURE THRUST WASHER RETAINER & SPRING BENDIX ASSEMBLY RETAINING RING DUST COVER...
  • Page 52 FIELD COIL FIELD COIL CONNECTORS CONNECTORS BRUSH CONNECTION POINT OF SPRINGS POWER CORD LEADS 12 VOLT 120 VOLT...
  • Page 54 MOUNTING HOLES MECHANISM FULL DOWN BEFORE SCREWS TORQUED ELECTRIC START INTERLOCK SWITCH...
  • Page 55 MOUNTING HOLES MECHANISM FULL DOWN BEFORE SCREWS TORQUED ELECTRIC START INTERLOCK SWITCH SCREW END MUST NOT BLOCK LEVER ACTION CABLE CLAMP SCREW MOUNTING HOLES MECHANISM FULL DOWN BEFORE SCREWS TORQUED...
  • Page 56 STANDARD PLUG...
  • Page 57 MAGNETS...
  • Page 59 Carbon Deposit Normal...
  • Page 60 .0125" (.3175 mm)

  • Page 61: Chapter 9 Internal Engine And Cylinder

    CHAPTER 9 INTERNAL ENGINE AND CYLINDER GENERAL INFORMATION OPERATION 4-CYCLE ENGINE THEORY INTAKE COMPRESSION POWER EXHAUST...
  • Page 62 LUBRICATION SYSTEMS The rotary pump is driven by the camshaft. It uses a lobed gear in a rotating ring to provide positive oil displacement (diag. 9). COUNTERBALANCE SYSTEMS COUNTER- BALANCE SHAFT...
  • Page 63 COMPONENTS cylinder block piston piston rings connecting rod cylinder head crankshaft camshaft valves valve springs valve lifters push rods rocker arms crankcase breather cylinder cover oil pump flywheel SHAFT ROTOR ROTARY PUMP RING...

  • Page 64: Engine Operation Problems

    ENGINE OPERATION PROBLEMS SURGES OR RUNS UNEVENLY ENGINE KNOCKS OVERHEATS Associated equipment loose or Excessive engine loading Fuel cap vent obstructed improperly adjusted Check for excessive carbon in Low oil level or wrong viscosity oil Dirty carburetor or air filter combustion chamber Loose flywheel examine key, key way Cooling air flow obstructed or clogged...
  • Page 65 ENGINE OPERATION PROBLEMS ENGINE VIBRATES EXCESSIVELY BREATHER PASSING OIL ENGINE MISFIRES Oil level too high Carburetor improperly adjusted Bent crankshaft Excessive RPM or improper governor Wrong or fouled spark plug Attached equipment out of balance setting Valves sticking or not seating properly Loose mounting bolts Damaged gaskets, seals or "O"...
  • Page 66 TESTING ENGINE KNOCKS ENGINE OVERHEATS SURGES or RUNS UNEVENLY ENGINE MISFIRES...
  • Page 67 ENGINE VIBRATES EXCESSIVELY BREATHER PASSING OIL 2 and 4-CYCLE RPM SETTINGS NOTE: NOTE: EXCESSIVE OIL CONSUMPTION...
  • Page 68 LACKS POWER SERVICE DISASSEMBLY PROCEDURE NOTE:...
  • Page 69 NOTE: ON SOME OHV ENGINES THE EXHAUST PUSH ROD CAN ONLY BE REMOVED AFTER THE HEAD IS OFF. YOU MUST HAVE IT BACK IN BEFORE RE- ASSEMBLY.
  • Page 71 CYLINDERS...
  • Page 72 CYLINDER HEAD AND VALVE TRAIN SERVICE TORQUE SEQUENCE Valves, Springs, And Push Rods TORQUE SEQUENCE...
  • Page 73 PISTONS, RINGS, AND CONNECTING RODS Piston Piston Rings Piston Ring Orientation NOTE:...
  • Page 74 CONNECTING RODS On all engine models, the match marks on the connecting rod and cap must align and face out when installing the piston assembly into the engine (diag. 33 & 34). CRANKSHAFTS AND CAMSHAFTS CAUTION: NEVER TRY TO STRAIGHTEN A BENT CRANKSHAFT.

  • Page 75: Valve Seats

    CRITICAL NOTE: Valve Seats...
  • Page 76 VALVE LIFTERS VALVE GUIDES VALVE GUIDE REMOVAL (WHERE APPLICABLE, CONSULT PARTS MANUAL) CAUTION : USE PROTECTION FOR EYES AND HANDS, BE CAREFUL ! THE HOT OIL AND HEAD CAN EASILY CAUSE BURNS. VALVE GUIDE INSTALLATION CAUTION : USE PROTECTION FOR EYES AND HANDS, BE CAREFUL ! THE HOT OIL AND HEAD CAN EASILY CAUSE BURNS.
  • Page 77 CRANKCASE BREATHERS Top Mounted Breather Side Mounted Breather...
  • Page 78 CYLINDER COVER, OIL SEAL, AND BEARING SERVICE Cylinder Cover Oil Seal Service NOTE: CRANKSHAFT BEARING SERVICE Ball Bearing Service...
  • Page 79 SERVICE BUSHING BUSHING SIZE CHART BUSHING SERVICE FINISHED REAM PART NUMBER BORE DIAMETER ENGINE ASSEMBLY...
  • Page 80 NOTE: Dual Balance Shaft NOTE:...
  • Page 81 SHAFT ROTOR On engines with ball bearings in the cover, install a thrust washer (if applicable) over the crankshaft, followed by the retaining ring. RING ROTARY PUMP NOTE: NOTE: INSTALL OIL PUMP AFTER THE SUMP IS ON EXCEPT NOTE:...
  • Page 82 STEPS 12A -12G APPLY ONLY TO EARLY PRODUCTION ENGINE MODELS OHM, OHSK120, OVM AND OVXL. b. Install the valves into the head, and using a new head gasket, place the head on the cylinder block. Tighten the head bolts in the numbered sequence using 60 inch pound (6.8 Nm) increments to the specified torque.
  • Page 83 OHH / OVRM LOCKING / ADJUSTING NUT CROWN DOWN "O" RING OR GASKET FEELER GAUGE PUSH ROD VALVE STEM ROCKER ARM GUIDE STUD TABS UP OVM / OHM / OVXL OHV 11-13 and OHV 110-135 / OHSK80-130...
  • Page 84 OHV135 - 175...
  • Page 85 NOTE:...
  • Page 86 The engine specifications listed on the following pages include tolerances that are considered acceptable to achieve normal engine operation. Observed values inside the listed tolerance range are satisfactory and require no adjustments.
  • Page 89 . t f & ) . l l f f l f f ) . t l f f l f f l f f l f f...
  • Page 92 TOOL KIT 670195E Kit contains tools for 2- and 4-cycle engines. Includes all items on this page but items may be purchased separately.

This manual is also suitable for:

Ohhsk50 - 130Ovrm120Ovxl/c120Ovxl120Ovxl125Ohv11 - ohv17 ... Show all

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