Tecumseh Quick Reference - Small Engine Suppliers

1 TecumsehQuick ReferenceService InformationCovers Engine and Transmission ProductForm R 7/001 IntroductionThis booklet contains the Quick Reference and basic trouble-shooting information previously found on Tecumseh wall chartsand in the Technician's booklet is designed to be used as a work bench quickreference guide when servicing Tecumseh engines and motiondrive 's Note: Tecumseh engines are manufactured to meet EPA and CARB standards. As a technician, it is unlawful to re-calibrate or replacea fuel nozzle or jet (bowl nut) with a part from any other carburetorthat was not originally designed for that Engine . All speed adjust-ments must remain within the limits that are specified for eachengine and are not to exceed the maximum. This can only bedeviated from if specifically approved by Tecumseh Products,EPA and : Torque specifications listed should not be confused with the torque value observed onengines which have been Torque specifications take relaxation into account so sufficient clamping force existsafter an Engine has reached operating listed are intended to cover highly critical areas.

2 More extensive torques are foundin the respective repair SpecificationsTWO-CYCLE Engine SERIES 840 - 850 TWO-CYCLE Engine SERIESL ocationInch lbs. TorqueNmEngine DesignationCrankcase to Flywheel Adapter Plate to Cylinder160-22018-25 TC TWO-CYCLE Engine SERIESL ocationInch lbs. Torque Nm Engine DesignationCylinder to Crankcase80-959-11 Crankcase Cover to Crankcase70-1008-11 Flywheel TWO-CYCLE Engine SERIES (AV520/600, TVS600, AH520, AH/HSK600)LocationInch lbs. TorqueNmEngine DesignationConnecting Housing Base to Cylinder Head to Cylinder100-14011-16 Flywheel Nut AV Industrial (Point Ignition) (670 Series AV 520 and All AV 600)Flywheel Nut ( Ignition) 3 NOTE: Refer to Technician's Handbook for a moredetailed list of remedies.*Carburetor Troubleshooting use Technician'sHandbook or Carburetor Troubleshooting Booklet,Form No. 695907.

3 Video No. Cycle TroubleshootingAs an aid in troubleshooting any piece of equipment, interview the customer, and review conditions andsymptoms of the problem. Examine exterior for clues: leaks, excessive dirt, damaged or new parts.(CONTINUED ON NEXT PAGE)Check fuel supplyand fuel cap ventWetDryDefectivespark plugImproper fuel mixor stale fuelCarburetionproblems due toflooding, overpriming, etc.*Restrictedair filterExhaust portspluggedCrankcase sealsor gaskets leakingIgnition SystemDamaged reed, portplugs, seals orgasketsPoorcompressionRestriction infuel system (filter,screen)FUEL SYSTEME ngine WillNot StartCheck if sparkplug is wet or dryReview with customerpriming or chokingprocedure(3-5 primes, ifequipped, waiting 2seconds betweeneach prime)Carburetion problem*(bad bowl gasket)4 NOTE: Refer to Technician's Handbook for a more detailed list of Cycle Troubleshooting - continuedIGNITION SYSTEME ngine WillNot StartReplace spark plugIsolate Engine from allequipment (disconnectwiring harness), repeattestNo SparkCheck for sparkSet proper point gap,check condensor andtiming (if equipped)Check electric starterif applicableSet proper air gap onexternal coilCheck flywheel forcorrect key, damagedkey or key adaptorTest coil forintermittent or weaksparkEquipment problem,check switches, wiringand equipmentcontrolsSparkParasitic load too highTest ignition moduleEngine problem,check for shorts orgrounds in wiringNo SparkSpark5 TVM & TVXL170-195-220 Torque SpecificationsFOUR-CYCLE LIGHT FRAME Engine SERIES(TVS, TNT, ECV, LAV, LEV, H, HS, OHH, OVRM and VLV)LocationInch lbs.

4 TorqueNmEngine DesignationRocker Arm Stud Lock Nut100-14011-16 Connecting Cylinder Head160-21018-24 Cylinder Head220-24025-27 Cylinder Mounting Flange or Cylinder Flywheel Nut (Cast Iron)500-60042-50 Flywheel Nut (Aluminum) TVSTNTECVLAVH/HSKHS/HSSKOVRMVLVLEVOHHNot e: Torque specifications listed should not be confused with the torque value observed onengines which have been Torque specifications take relaxation into account so sufficient clamping force existsafter an Engine has reached operating listed are intended to cover highly critical areas. More extensive torques are foundin the respective repair DesignationTorqueHM/HMSK70-100 OVM/OVXL,OHV120-125 OHSK80-130 OHM120 TVM125, 140H50-60V70H70 OHV135-145203 204 SeriesOHV11-13,OHV110-135, 206 SeriesFOUR-CYCLE MEDIUM FRAME Engine SERIES(TVM, TVXL, H, V, HM, OVM, OVXL, OHM, OHSK and OHV)Connecting Connecting Connecting Cylinder Head Bolts220-24025-27 Cylinder Head Cylinder Head Bolts160-21018-24 Rocker Adj.

5 Lock Screw65-807-9 Rocker Arm Stud Lock Rocker Arm Hex Jam Nut15-202 Rocker Arm Studs170-21019-24 Rocker Arm Box to Rocker Box Cover15-202 Rocker Box Cover (Four Screw) Mounting Flange or Cylinder Mounting Flange or Cylinder Flywheel Nut400-55045-62 Flywheel Nut (External Ignition)600-80068-90 6 Torque Specifications - continuedHHVHOHL ocationInch DesignationTorqueTVTFOUR-CYCLE LARGE FRAME Engine SERIES (CAST IRON BLOCK HH, VH and OH)Connecting Cylinder Mounting Flange & Cylinder Rocker Arm Shaft to Rocker Arm Box to Cylinder Head80-909-10 Flywheel FOUR-CYCLE HEAVY FRAME Engine SERIES (V-TWIN)LocationInch DesignationTorqueConnecting Cylinder Head Bolts220-24025-27 Rocker Arm Jam Rocker Arm Cover Mounting Screw526 Mounting Flange/Cylinder Cover240-26027-29 Flywheel Nut600-80068-90 7 Four Cycle TroubleshootingAs an aid in troubleshooting any piece of equipment, interview the customer, and reviewconditions and symptoms of problem.

6 Examine exterior for clues: leaks, excessive dirt,damaged or new : Refer to Technician's Handbook for a more detailed list of remedies.*Carburetor Troubleshooting, use Technician's Handbook or Carburetor TroubleshootingBooklet, Form No. 695907. Video No. orstale fuelCheck if spark plug iswet or dryFUEL SYSTEME ngine WillNot StartDefectivespark plugWetRestricted air filterCarburetion problemsdue to flooding, overpriming, etc.*Ignition systemReview with thecustomer properpriming procedure(3-5 primes, waiting2 seconds betweeneach prime)DryPoorcompressionCheck fuel supply andfuel cap ventRestriction in fuelsystem (filter)Carburetion problem*(bad bowl gasket)If equipped with achoke, check for fulltravel. Check throttlecable and control forproper Cycle Troubleshooting - continuedNOTE: Refer to Technician's Handbook for a more detailed list of SYSTEME ngine WillNot StartNo SparkSparkCheck forsparkSparkSet proper point gap,check condensor andtimingNo SparkReplace spark plugIsolate Engine from allequipment (disconnectwiring harness), repeattestParasitic load toohighTest coil forintermittent or weaksparkSet proper air gap onexternal coilCheck flywheel forcorrect key, damagedor sheared keyTest ignitionmoduleEngine problem,check for shorts orgrounds in wiringEquipment problem,check switches,wiring andequipment controls91 Tecumseh 2 Cycle Diaphragm AdjustmentsNOTE: For meeting emission requirements, somecarburetors have fixed-main or idle jets.

7 Theabsence of the adjustment screw indicates fixedjets and no adjustment is mixture adjusting screws in finger tight to theclosed position, then one (1) turn out from closedposition. This setting is approximate. This will allowthe Engine to be started so the carburetor can be the Engine and let it warm up for approximately3-5 minutes. Do not adjust the carburetor whenthe Engine is the throttle control to idle. If it is a fixed speedtype, manually hold the throttle against the idlespeed adjustment throttle lever must be held against the crack screw for low speed adjustments or all adjustments willbe incorrect and cause poor performance and unsatisfactory the Engine idling and throttle lever against the idle speed regulating screw, turn the low speedadjustment screw slowly clockwise from the NORMAL setting until the Engine falters. Remember thislocation.

8 Turn the screw counterclockwise until Engine just starts to sputter or drops in Rememberthis location. Turn the screw clockwise until it is halfway between your first position where the enginefaltered and your last position where the Engine started to sputter. This will be the optimum low speed settingon your run the Engine at governed speed. The high speed adjustments are made basically the same as thelow speed adjustments, with the exception of the settings being made 1/8 of a turn at a time, from theNORMAL settings. NOTE: It may be necessary to re-check the idle mixture adjustment after performingthe high speed the mixture adjustment screw finger tight to the closed position, then one (1) turn out from the closedposition. This setting is approximate and will allow the Engine to be started so the carburetor can be the Engine and let it warm up for approximately 3-5 minutes. Do not adjust the carburetor when theengine is the throttle control to idle.

9 If it is a fixed speed type, manually hold the throttle against the idle speedadjustment :If the Engine falters or stops after the choke lever is moved to the "OFF" position, open the mixtureadjusting screw 1/4 turn (counterclockwise) and restart the the Engine running, place the speed control in the "slow" position to make mixture adjustments. Turnthe mixture screw slowly clockwise from the NORMAL setting until the Engine falters. Remember thislocation. Turn the screw counterclockwise until the Engine just starts to sputter or drops in Rememberthis location. Turn the screw clockwise until it is halfway between your first position where the enginefaltered and your last position where the Engine started to sputter. This will be the optimum setting on MIXTURESCREWMAIN MIXTURESCREWNOTE: If no tensionspring is present, itmay be a fixed Series Governor Adjustment1. AIR VANE2. BACKLASH SPRING3.

10 GOVERNOR LINK4. GOVERNOR SPRING5. MOUNTING SCREW6. SPEED ADJUSTMENT SCREW7. SPEED CONTROL BODY8. SPEED CONTROL LEVER9. SPEED CONTROL PLUNGER14976 HIGH SPEEDGOVERNORADJUSTMENTINSERT THROTTLELINK AND SPRINGHEREOUT TO INCREASEIN TO DECREASETYPE I(style 1)TYPE I(style 2)SPEEDADJUSTINGLEVER23 SPEEDADJUSTINGLEVERTYPE II:(style 3)Three different styles of governor systems are usedon TC engines. Use the following illustrations ( and 3) to identify the governor system used andthe following procedure to adjust the governedengine the Engine to run for at least 5 minutes toreach operating temperature. Make sure the airfilter (if equipped) is clean and the choke is in theoff a Vibratach (part# 670156) or othertachometer, determine the Engine 's atidle and wide open throttle. Refer to Microfichecard 30, or a computer parts look-up program toobtain the recommended Engine the applicable illustration, either bend thespeed adjusting lever toward the spark plug endof the Engine to decrease high speed , orbend the lever in the opposite direction to On TC Type II engines, turn the speedadjusting screw out to increase or in to decreaseengine high speed If the speed adjustmentscrew is turned out to increase the Engine ,the speed control lever must be moved to allowthe speed control plunger to contact the speedadjustment low speed is set by moving the throttlecontrol to the lowest speed position and adjustingthe low speed adjustment screw on the TO INCREASE SPEEDBEND TO DECREASE SPEEDS pring ColorSpring PositionOrange or Green1 Pink, Red.