Craftsman 143.991200 Specifications

This manual covers engine models:OHH50 - 65, OHHSK50 - 130, OHV11 - OHV17, OVM120,OVRM40-675, OVRM120, OVXL/C120, OVXL120, OVXL125.4-CYCLEOVERHEADVAL

7Polyurethane-Type Filter Element or pre-cleanerThis type of air filter or pre-cleaner can be serviced when restricted with dust or dirt. Wash the fil

8CHAPTER 3 CARBURETORS AND FUEL SYSTEMS1GENERAL INFORMATIONTecumseh overhead valve engines use float type carburetors. Float type carburetors use a ho

9For the fuel to flow, the carburetor bowl must be eithervented externally or internally. Some internallyvented float style carburetors use a tygon t

10CARBURETOR VISUAL IDENTIFICATIONSeries1 CarburetorsSeries 1 carburetors are used on some 4 - 7 modeloverhead valve engines. This float style carbure

111415Series 10This carburetor is for use on all season engineapplications. It is the equivalent of the series "8" withthe addition of a ch

12TESTING1. After repeated efforts to start the engine using the procedure listed in the operators manual fail, checkfor spark by removing the high t

13Pre-sets and Adjustments (Tecumseh andWalbro carburetors)Turn both the main and idle mixture adjusting screwsin (clockwise) until finger tight if ap

14If further adjustment is required, the main adjustment should be made under a load condition.If the engine stops or hesitates while engaging the loa

158. Remove the primer bulb (if equipped) bygrasping with a pliers and pulling and twistingout of the body. Remove the retainer by pryingand lifting o

1633Idle and High Speed Mixture Adjusting Screw35FUEL-INLETIDLE FUELTRANSFERPASSAGEFUEL-METERINGPORTONE-HOLE TYPETW0-HOLE TYPE3411 / 64" (4.36 mm

iCONTENTSC Tecumseh Products Company 1998PageCHAPTER 1 GENERAL INFORMATION ... 1ENGINE IDENTIFICATION ...

1738SERIES 8, 9 & 10NEEDLE &SEATFLOATSPRING37FLOAT HINGEPINSEATRETAININGRINGIDLE RESTRICTIONBOWL'O' RINGMAIN JETGASKETBOWL RETAINER

18THROTTLELEVER43TWELVEO'CLOCKPOSITIONTHROTTLEPLATE42THREEO'CLOCKPOSITION4445WALBRO LMK SERIESTHROTTLE LEVERTHROTTLE PLATESERIES 7DUST SEAL

19Choke Shaft and PlateThe choke plate is inserted into the air horn of thecarburetor in such a position that the flat surface (ifapplicable) of the c

20SEAT5/32" (3.969 mm)FLAT PUNCHTHROTTLEENDCLIPCHOKEEND5152Inlet Needle and SeatMake sure the seat cavity is clean. Moisten the seatwith oil and

21Fuel Bowl And Bowl NutWhenever a carburetor bowl is removed for service,the fuel bowl O ring (or gasket on Series "7") andthe bowl nut w

22CHAPTER 4 GOVERNORS AND LINKAGEGOVERNOR GEARWEIGHTSTHROTTLESPRINGGENERAL INFORMATIONTecumseh 4 cycle engines are equipped with mechanical type gover

232GOVERNORCLAMPSCREWÝPUSHLEVER TOWIDE OPENTHROTTLETURN CLIP COUNTERCLOCKWISE ON ALL VERTICALSHAFT ENGINES EXCEPT VLV & VLXL. CLOCKWISEON ALL HORI

24Governor Shaft Replacement, Retaining Ring Style1. Remove the retaining ring, spool, gear assembly, and washer(s).2. Clamp the shaft in a vise and p

25Speed Controls And LinkageMany different types of speed controls and linkage are used for O.E.M. applications. Linkage attachmentpoints are best rec

2618NOTE: ON REMOTECONTROL THISWILL NOTBE PRESENTLOW SPEED ADJUSTHIGH SPEED ADJUST19OVRM OVRMOVRM SNAP IN CONTROLLOW SPEED TABHIGH SPEED TABHIGH SPEE

iiTESTING PROCEDURE ... 40STARTING CIRCUIT ... 40CHA

27CONVERSION TO REMOTE CONTROLRemove the manual control knob by squeezing together with a pliers or prying with a screw driver. Removethe air cleaner

28OVM, OVXL, OHV VERTICAL SPEEDCONTROLThis remote speed control may have governed idle, achoke override, and the option of an ignition remotestop term

29CHAPTER 5 RECOIL STARTERSGENERAL INFORMATIONRecoil starters used on vertical shaft Tecumseh engines are top mount horizontal pull style. Horizontal

30534CAUTION: HANDLE MATCHES SAFELY TOAVOID BURNS, AND EXTINGUISHCOMPLETELY BEFORE DISCARDING.# 4 1/2 rope = 9/64" diameter (3.572 mm)# 5 rope =

31PULLEY AND REWINDSPRING ASSY.BRAKE SPRINGSTARTER DOGDOGSPRINGWASHERSPRING PINSTARTER HOUSINGHANDLEINSERTROPEHANDLEWASHERRETAINER6ROPESTARTERHOUSINGH

324. Use a small Phillips screwdriver or similar toolto pry the retainer legs apart and lift out theretaining wedge.5. Pinch the legs of the retainer

33Assembly ProcedureNOTE: This procedure covers three starters. Followillustration of your starter type as shown.1. Place the rewind spring and keeper

34BRAKE SPRING14LEFT-HANDKNOTStylized Starter (OHV 13.5 -17)1. Remove the starter handle by first pulling alength of rope out using the handle, tying

35CHAPTER 6 ELECTRICAL SYSTEMSEND CAPBRUSH SPRINGSBRUSH CARDHOUSINGENGAGING NUTGEAR12OPERATIONSTARTING CIRCUIT AND ELECTRIC STARTERSGENERAL INFORMATIO

36CONVERTING ALTERNATING CURRENTTO DIRECT CURRENTIn order to charge a battery, it is necessary to convertalternating current (A.C.) to direct current

1CHAPTER 1 GENERAL INFORMATIONENGINE IDENTIFICATIONTecumseh engine model, specification, and serialnumbers or date of manufacture (D.O.M.) are stamped

37WIRE GAUGE: The proper thickness of wire isnecessary in all electrical circuits. Wire diameter ismeasured in increments of gauge numbers. As thegaug

38Starter turns atlow rpms orstalls under loadIs there powerat the powersource?NONOYESYESStarter will notturnIntermittentstarter operationIs power sup

39Check diodes,replace if nocontinuity exists or ifcontinuity existsreversing test leadsCheck fuses, replaceas necessaryCheck switches,wiring, or ligh

40TESTING PROCEDURESTARTING CIRCUIT1. Check the power source using an electrical tester and following the tester's recommended procedure.Make sur

4118 Watt A.C. Lighting AlternatorCHECKING THE SYSTEM: To check the system,disconnect the plug from the rest of the lightingsystem. Connect a wire lea

423 AMP DC ALTERNATOR SYSTEM -DIODE IN HARNESS SLEEVEThis system has a diode included in the red wire whichconverts the alternating current (A.C.) to

43145 AMP D.C. ALTERNATOR SYSTEMREGULATOR-RECTIFIER UNDERBLOWER HOUSINGCHECKING THE SYSTEM: An open circuit D.C.voltage check cannot be made with thi

44CHECKING THE SYSTEM: To check the system,disconnect the plug and measure the D.C. voltage atthe red wire terminal (diag. 16). Measure the A.C.voltag

45INSERT PROBES INTOCONNECTOR SLOTS DONOT REMOVECONNECTOR WIRESA.C. VOLTMETERYELLOWCAUTION: BLOWERHOUSING MUST BEINSTALLED WHENRUNNING ENGINEMAGNETO G

46A.C. OUTPUTYELLOW16 Amp Alternator System with External RegulatorCHECKING THE SYSTEM: An open circuit D.C. voltage check cannot be made with this sy

SHORT BLOCKSNew short blocks are identified by a tag marked S.B.H.(Short Block Horizontal) or S.B.V. (Short BlockVertical). Original model identificat

47LOW OIL SHUTDOWN SWITCHESCheck the LOS switch while it is in the engine. Theengine must be level, and the oil level at the full mark.Place the spee

48LOW OIL SENSORThis sensor must use a # 194 bulb in series with thesensor for proper operation and to prevent sensordamage. Remove the sensor from th

4912 VOLT120 VOLTBRUSHSPRINGSCONNECTION POINT OFPOWER CORD LEADS33 32FIELD COILCONNECTORSFIELD COILCONNECTORSInspection And Repair1. The pinion gear p

50CHAPTER 7 FLYWHEEL BRAKE SYSTEMSGENERAL INFORMATIONTecumseh’s brake systems are required to meet compliance standards which has become a federal law

513TOP VIEWBRAKE PADGROUNDINGCLIP POSITIONLINKAGE4MOUNTING HOLESÔMECHANISM FULL DOWNBEFORE SCREWS TORQUEDELECTRIC START INTERLOCK SWITCHCOMPONENTSThe

52CABLE CLAMPSCREWÔÔMECHANISM FULL DOWNBEFORE SCREWS TORQUEDBRAKE BRACKET ASSEMBLYLate production brake brackets are serviceable only by installing a

53 CHAPTER 8 IGNITIONOPERATIONSOLID STATE IGNITION SYSTEM (CDI)As the magnets in the flywheel rotate past the chargecoil, electrical energy is produce

54The flywheel with magnets provide the magnetic flux(or field) which is necessary to induce voltage andtrigger the module to provide spark.The flywhe

55Equipment problem,check switches, wiringand equipment controlsSparkNo SparkSparkEngine runserratically or shutsoff, restartsEngine WillNot StartChec

56SERVICETo remove the ignition module or the flywheel fromthe engine, see Chapter 9 under "Disassembly".SPARK PLUG SERVICESpark plugs shoul

3Oil Change Intervals: Change the oil after the first two (2) hours of operation and every 25 hours thereafter(OHH & OHSK50-130, OHV13.5-17 every

57IGNITION TIMING CHECKIn order for an engine to run effectively and efficiently,the spark must ignite the compressed air-fuel mixturewhen the piston

58CHAPTER 9 INTERNAL ENGINE AND CYLINDEROPERATION4-CYCLE ENGINE THEORYAll 4-cycle engines require four piston strokes orcycles to complete one power c

59FLANGE10COUNTER-BALANCESHAFTLUBRICATION SYSTEMSThe lubrication system used with all Tecumsehhorizontal crankshaft engines covered in this manualutil

6010COMPONENTSThe cylinder block houses the piston, crankshaft, and along with the cylinder cover all the internal components.The block is a one piece

61ENGINE OPERATION PROBLEMSSURGES OR RUNS UNEVENLYFuel cap vent obstructedExcessive engine loadingOVERHEATSENGINE KNOCKSAssociated equipment loose or

62ENGINE OPERATION PROBLEMSENGINE MISFIRESImproper Valve LashWeak valve springExcessive carbon build upCarburetor improperly adjustedIgnition timing o

63TESTINGENGINE KNOCKS1. Check the blade hub, blade adapter, or crankshaft coupler for loose fit, loose bolts, or crankshaft keydamage. Remove, inspec

64ENGINE VIBRATES EXCESSIVELY1. Remove the spark plug wire. Check the engine crankshaft on the PTO end for bends using a straightedge, square or a dia

651413METAL HAMMERKNOCK OFF TOOLSCREWDRIVERTO RAISEFLYWHEEL12FLYWHEELTOOLFLYWHEELSOCKET WRENCHLACKS POWER1. Check the air intake for an obstruction (

6610. Remove the flywheel key and alternator ifequipped, and baffle plate.11. Remove the muffler.12. Remove the intake pipe, spacer if equipped, andth

4STORAGE (IF THE ENGINE IS TO BE UNUSED FOR 30 DAYS OR MORE)CAUTION: NEVER STORE THE ENGINE WITH FUEL IN THE TANK INDOORS OR IN ENCLOSED,POORLY VENTI

6715. Remove the cylinder cover or mounting flangeusing a seal protector positioned on the seal toprevent seal damage. The crankshaft must befree of r

68CYLINDERSVisually check the cylinder for broken or cracked finsor a scored cylinder bore. Check the main bearing forwear or scoring. If the main bea

692512354142635STEMMINIMUMDIMENSION1/32"(.794 mm)MARGIN450FACETORQUE SEQUENCEOVRM / OHH, OHSK50 - 70TORQUE SEQUENCEOHV 11 - 17, OHM, OHSK80 - 130

7031PISTONCYLINDER2930PISTON RINGPISTON MEASUREMENTS ARE TAKEN ATBOTTOM OF SKIRT 900 FROM WRIST PIN HOLE28INDICATES.010" (.254 mm)OVERSIZE PISTON

71323433CONNECTING RODSSome engine models have offset piston pins (notcentered) to centralize the combustion force on thepiston. When installing the c

72SEAT CUTTERSEAT4241310SEAT40150600BOTTOMNARROWINGCUTTERBOTTOMNARROW3/64" SEATTOPNARROWTOP NARROWINGCUTTER460310460BOTTOMNARROWINGMechanical Com

73VALVE LIFTERSWhen removing the lifters, mark the lifters to install the lifter in the same position as it was removed from. Thevalve lifters may be

74CRANKCASE BREATHERSThe breather element and case can be cleaned usingcleaning solvent. Make sure the small drain hole orholes are clean and installe

755051OIL SEALOIL SEAL REMOVERTOOL: POSITIONED FORREMOVAL OF OIL SEALOIL SEALDRIVER 670272OIL SEALDRIVERPROTECTOROIL SEALCYLINDER COVER, OIL SEAL, AND

76MATCH MARKSDURLOCK BOLTOIL SEALPROTECTORSERVICE BUSHINGWe are supplying this bushing for service repair. After the bushing has been installed, it re

5CHAPTER 2 AIR CLEANERSCOMPONENTSThe cover holds the filter element and prevents largedebris from entering the filter body.The polyurethane wrap pre-

7759ULTRA-BALANCE®TIMING58CAM TIMING57CHAMPFER UPTOWARD CAMCAMSHAFTCOMPRESSIONRELEASE SPRINGTHRUSTWASHERBA5556SCREW"O" RINGOIL PUMP COVEROIL

788. Mount the cylinder cover or flange with thegovernor gear assembly installed to thecrankcase using dowel pins to position thecover and a new gaske

79Install the cylinder head using a new headgasket. On OHV 11-13 models, place thepush rods in the block before installing thehead and head gasket. Ti

80g. Compress the valve spring with the tooland insert the two retainers into the keeperso the inside ridge of the retainer locks intothe valve stem g

81On models OHV 135 - 175 hold a 1/2"(12.7 mm) wrench on the rocker arm bearingwhile tightening the 5/32" Allen head set screwto 175 in. lbs

82CHAPTER 10ENGINE SPECIFICATIONS ANDSEARS CRAFTSMAN CROSS-REFERENCEThe engine specifications listed on the following pages include tolerances that ar

83ENGINE SPECIFICATIONSOVRM40 OVRM50-6.75 OVRM120 OHH50 Specifications OVRM105 OHSK50Standard Metric Standard Metric Standard Metric Standard MetricEn

84OHH and OHSK80 - 110 OHM, OHSK, OVM, OHV13.5 - 17OHSK55 - 70 OVXL120,130 Specifications Note (D) & OHV11-13Standard Metric Standard Metric Stan

85OVERHEAD VALVE TORQUE SPECIFICATIONSThe torque specifications listed in this chart are to be used for replacing components after disassembly, not fo

86OVERHEAD VALVE TORQUE SPECIFICATIONSThe torque specifications listed in this chart are to be used for replacing components after disassembly, not fo

6DISASSEMBLY PROCEDURE1. Unlock the tabs or remove the screws or wingnuts holding the air cleaner cover in place.2. Remove the hex nuts holding the el

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87CHAPTER 11. EDUCATIONAL MATERIALSAND TOOLSAVAILABLE TECHNICIAN'S HANDBOOKS692508Covers the diagnosis and repair of Tecumseh 2-cycleengines. Exc

88TOOLSTOOL KIT 670195EKit contains tools for 2- and 4-cycle engines.Includes all items on this page but items may be purchased separately.Main Menu

89OIL SEAL DRIVERNo. 670195D Tool Kit. Contains special toolscommonly used in servicing 2 and 4 cycle engines.OIL SEAL PROTECTOR/INSTALLERConsult the

90B.C.A.D.No. 670298 Alignment Tool.1/32" (.794 mm)OVERSIZE VALVE GUIDE REAMERNo. 670283. Used on OHH on Intake and Exhaust,and OVRM40-60 Intake