Tecumseh Quick Reference

TecumsehQuick ReferenceService InformationCovers Engine and Transmission Product

Form No.695933 R 7/00

1IntroductionThis booklet contains the quick reference and basic trouble-shooting information previously found on Tecumseh wall chartsand in the Technician's Handbooks.

This booklet is designed to be used as a work bench quickreference guide when servicing Tecumseh engines and motiondrive systems.

Technician's Note:Tecumseh engines are manufactured to meet EPA and CARBstandards. 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 CARB.

2TV

S

TV

XL

HS

K

HX

L

TC

200

TC

300

AV

520/

600

TV

S60

0

AH

/HS

K60

0

AH

520

TC

H20

0/30

0

Note: Torque specifications listed should not be confused with the torque value observed onengines which have been run.The Torque specifications take relaxation into account so sufficient clamping force existsafter an engine has reached operating temperature.Torques listed are intended to cover highly critical areas. More extensive torques are foundin the respective repair manual.

Torque SpecificationsTWO-CYCLE ENGINE SERIES

840 - 850 TWO-CYCLE ENGINE SERIES

Location Inch lbs. Torque Nm Engine Designation

Crankcase to Cylinder 120-204 13.5-23 Flywheel Nut 360-420 41-47.5 Adapter Plate to Cylinder 160-220 18-25

TC TWO-CYCLE ENGINE SERIES


Cylinder to Crankcase 80-95 9-11 Crankcase Cover to Crankcase 70-100 8-11 Flywheel Nut 190-250 21.5-28.5

TWO-CYCLE ENGINE SERIES (AV520/600, TVS600, AH520, AH/HSK600)


Connecting Rod 40-50 4.5-5.5 Housing Base to Cylinder 80-120 9-13.5 Cylinder Head to Cylinder 100-140 11-16 Flywheel Nut AV Industrial (Point Ignition) 216-300 24.5-34 (670 Series AV 520 and All AV 600)Flywheel Nut (C.D. Ignition) 264-324 30-36.5

3NOTE: Refer to Technician's Handbook for a moredetailed list of remedies.

*Carburetor Troubleshooting use Technician'sHandbook or Carburetor Troubleshooting Booklet,Form No. 695907. Video No. 695015.

Two Cycle Troubleshooting

As 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 vent

Wet Dry

Defectivespark plug

Improper fuel mixor stale fuel

Carburetionproblems due to

flooding, overpriming, etc.*

Restrictedair filter

Exhaust portsplugged

Crankcase sealsor gaskets leaking

Ignition System

Damaged reed, portplugs, seals or

gaskets

Poorcompression

Restriction infuel system (filter,

screen)

FUEL SYSTEM

Engine WillNot Start

Check if sparkplug is wet or dry

Review with customerpriming or choking

procedure(3-5 primes, if

equipped, waiting 2seconds between

each prime)

Carburetion problem*(bad bowl gasket)

4NOTE: Refer to Technician's Handbook for a more detailed list of remedies.

Two Cycle Troubleshooting - continued

IGNITION SYSTEM


Replace spark plug

Isolate engine from allequipment (disconnectwiring harness), repeat

test

No Spark

Check for spark

Set proper point gap,check condensor andtiming (if equipped)

Check electric starterif applicable

Set proper air gap onexternal coil

Check flywheel forcorrect key, damaged

key or key adaptor

Test coil forintermittent or weak

spark

Equipment problem,check switches, wiring

and equipmentcontrols

Spark

Parasitic load too high Test ignition module

Engine problem,check for shorts orgrounds in wiring

No Spark

Spark

5TV

M &

TV

XL

17

0-1

95

-22

0

Torque SpecificationsFOUR-CYCLE LIGHT FRAME ENGINE SERIES(TVS, TNT, ECV, LAV, LEV, H, HS, OHH, OVRM and VLV)


Rocker Arm Stud Lock Nut 100-140 11-16 Connecting Rod 95-110 11-12.5 Cylinder Head 160-210 18-24 Cylinder Head 220-240 25-27 Cylinder Head 180-220 20.5-25 Mounting Flange or Cylinder Cover 100-130 11-14.5 Flywheel Nut (Cast Iron) 500-600 42-50 Flywheel Nut (Aluminum) 400-500 45-56.5

TV

S

TN

T

EC

V

LA

V

H/H

SK

HS

/HS

SK

OV

RM

VL

VL

EV

OH

H

Note: Torque specifications listed should not be confused with the torque value observed onengines which have been run.The Torque specifications take relaxation into account so sufficient clamping force existsafter an engine has reached operating temperature.Torques listed are intended to cover highly critical areas. More extensive torques are foundin the respective repair manual.

Location Inch lbs. Nm Engine DesignationTorque

HM

/HM

SK

70-1

00

OV

M/O

VX

L,

OH

V12

0-12

5

OH

SK

80-1

30O

HM

120

TV

M12

5, 1

40

H50

-60

V7

0

H70

OH

V13

5-14

520

3 S

erie

sO

HV

15-1

7.5

204

Ser

ies

OH

V11

-13,

OH

V11

0-13

5, 2

06 S

erie

s

FOUR-CYCLE MEDIUM FRAME ENGINE SERIES(TVM, TVXL, H, V, HM, OVM, OVXL, OHM, OHSK and OHV)

Connecting Rod 160-180 18-20.5 Connecting Rod 200-220 22.5-25 Connecting Rod 200-240 22.5-27 Cylinder Head Bolts 220-240 25-27 Cylinder Head Bolts 180-240 20.5-27 Cylinder Head Bolts 160-210 18-24 Rocker Adj. Lock Screw 65-80 7-9 Rocker Arm Stud Lock Nut 110-130 12.5-14.5 Rocker Arm Hex Jam Nut 15-20 2 Rocker Arm Studs 170-210 19-24 Rocker Arm Box to Head 75-130 8.5-14.5 Rocker Box Cover 15-20 2 Rocker Box Cover (Four Screw) 40-65 4.5-7 Mounting Flange or Cylinder Cover 100-130 11-14.5 Mounting Flange or Cylinder Cover 110-140 12.5-16 Flywheel Nut 400-550 45-62 Flywheel Nut (External Ignition) 600-800 68-90

6Torque Specifications - continued

HH

VH

OH


TV

T

FOUR-CYCLE LARGE FRAME ENGINE SERIES (CAST IRON BLOCK HH, VH and OH)

Connecting Rod 86-110 10-12.5 Cylinder Head 180-240 20.5-27 Mounting Flange & Cylinder Cover 100-130 11-14.5 Rocker Arm Shaft to Box 180-220 20.5-25 Rocker Arm Box to Cylinder Head 80-90 9-10 Flywheel Nut 600-660 68-74.5

FOUR-CYCLE HEAVY FRAME ENGINE SERIES (V-TWIN)


Connecting Rod 200-220 22.5-25 Cylinder Head Bolts 220-240 25-27 Rocker Arm Jam Nut 110-130 12.5-14.5 Rocker Arm Cover Mounting Screw 52 6 Mounting Flange/Cylinder Cover 240-260 27-29 Flywheel Nut 600-800 68-90

7Four Cycle TroubleshootingAs an aid in troubleshooting any piece of equipment, interview the customer, and reviewconditions and symptoms of problem. Examine exterior for clues: leaks, excessive dirt,damaged or new parts.

NOTE: 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. 695015.

Improper orstale fuel

Check if spark plug iswet or dry

FUEL SYSTEM


Defectivespark plug

Wet

Restricted air filter

Carburetion problemsdue to flooding, over

priming, etc.*

Ignition system

Review with thecustomer proper

priming procedure(3-5 primes, waiting2 seconds between

each prime)

Dry

Poorcompression

Check fuel supply andfuel cap vent

Restriction in fuelsystem (filter)

Carburetion problem*(bad bowl gasket)

If equipped with achoke, check for full

travel. Check throttlecable and control forproper adjustment.

8Four Cycle Troubleshooting - continued

NOTE: Refer to Technician's Handbook for a more detailed list of remedies.

IGNITION SYSTEM


No SparkSpark

Check forspark

Spark

Set proper point gap,check condensor and

timing

No Spark

Replace spark plug

Isolate engine from allequipment (disconnectwiring harness), repeat

test

Parasitic load toohigh

Test coil forintermittent or weak

spark

Set proper air gap onexternal coil

Check flywheel forcorrect key, damaged

or sheared key

Test ignitionmodule

Engine problem,check for shorts orgrounds in wiring

Equipment problem,check switches,

wiring andequipment controls

91

Tecumseh 2 Cycle Diaphragm AdjustmentsNOTE: For meeting emission requirements, somecarburetors have fixed-main or idle jets. Theabsence of the adjustment screw indicates fixedjets and no adjustment is necessary.

Diaphragm-Dual Adjustment.Turn 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 finetuned.

Start the engine and let it warm up for approximately3-5 minutes. Do not adjust the carburetor whenthe engine is cold.

Set the throttle control to idle. If it is a fixed speedtype, manually hold the throttle against the idlespeed adjustment screw.

The throttle lever must be held against the crack screw for low speed adjustments or all adjustments willbe incorrect and cause poor performance and unsatisfactory operation.

With 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. Turn the screw counterclockwise until engine just starts to sputter or drops in R.P.M.. 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 carburetor.

Next 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 adjustment.

Diaphragm-Single Adjustment.Turn 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 fine-tuned.

Start the engine and let it warm up for approximately 3-5 minutes. Do not adjust the carburetor when theengine is cold.

Set the throttle control to idle. If it is a fixed speed type, manually hold the throttle against the idle speedadjustment screw.

NOTE: 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 engine.

With 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 R.P.M. 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 yourcarburetor.

IDLE MIXTURESCREW

MAIN MIXTURESCREW

NOTE: If no tensionspring is present, itmay be a fixed jet.

10

TC Series Governor Adjustment

1. AIR VANE2. BACKLASH SPRING3. GOVERNOR LINK4. GOVERNOR SPRING5. MOUNTING SCREW6. SPEED ADJUSTMENT SCREW7. SPEED CONTROL BODY8. SPEED CONTROL LEVER9. SPEED CONTROL PLUNGER

1

4

9

7

6

HIGH SPEEDGOVERNORADJUSTMENT

INSERT THROTTLELINK AND SPRINGHERE

OUT TO INCREASE

IN TO DECREASE

TYPE I

(style 1)

TYPE I

(style 2)

SPEEDADJUSTINGLEVER

2

3

SPEEDADJUSTINGLEVER

TYPE II:

(style 3)

Three different styles of governor systems are usedon TC engines. Use the following illustrations (diags.2 and 3) to identify the governor system used andthe following procedure to adjust the governedengine speed.1. Allow the engine to run for at least 5 minutes to

reach operating temperature. Make sure the airfilter (if equipped) is clean and the choke is in theoff position.

2. Using a Vibratach (part# 670156) or othertachometer, determine the engine's R.P.M. atidle and wide open throttle. Refer to Microfichecard 30, or a computer parts look-up program toobtain the recommended engine speeds.

3. Using the applicable illustration, either bend thespeed adjusting lever toward the spark plug endof the engine to decrease high speed R.P.M., orbend the lever in the opposite direction to increaseR.P.M. On TC Type II engines, turn the speedadjusting screw out to increase or in to decreaseengine high speed R.P.M. If the speed adjustmentscrew is turned out to increase the engine R.P.M.,the speed control lever must be moved to allowthe speed control plunger to contact the speedadjustment screw.

4. The low speed is set by moving the throttlecontrol to the lowest speed position and adjustingthe low speed adjustment screw on the carburetor.

BEND TO INCREASE SPEED

BEND TO DECREASE SPEED

Spring Color Spring Position

Orange or Green 1

Pink, Red, or Black 2

SPRING

SPRINGPOSITION 1

POSITION 2

3

24

15

8

HOOKSPRING ONNOTCH

HOOKSPRING ONNOTCH

HOOKSPRING ONNOTCH

11

IDLE MIXTURESCREW

IDLE SPEED ADJUSTMENTSCREW

4

Carburetor Pre-Set and AdjustmentBoth the Walbro and the Tillotson carburetors usedon TC engines have non-adjustable main mixturejets. Only the idle mixture is adjustable by turningthe idle mixture screw. Use the following procedureto pre-set the idle mixture screw. Turn the idlemixture screw (clockwise) finger tight to the closedposition, then turn the screw counterclockwise toobtain the proper preset (diag. 4).Walbro Model WTA, WT 1 - 1-1/8 turnsTillotson Model HU 1-1/4 - 1-3/8 turns

Final Idle Mixture AdjustmentStart the engine and allow it to reach normal operatingtemperature (after 3-5 minutes). As the speed controlis set at the idle position, turn the idle mixture screwslowly clockwise until the engine R.P.M. just startsto decrease. Stop and note this screw position. Turnthe idle mixture screw slowly counterclockwise, theengine will increase in R.P.M. Continue to slowlyturn the screw until the engine R.P.M. starts todecrease. Note this position and turn the mixturescrew back clockwise halfway between the twoengine R.P.M. drop off positions. The idle mixtureadjustment is complete.Some carburetors came equipped with a mainmixture adjusting screw. To adjust the main mixture,follow the steps for idle adjustment.

Walbro (WTA, WT) and Tillotson (HU) Diaphragm Adjustment

4a

Emissionized TillotsonSimilar in design and operation, the Tillotsonemission carburetor uses a fixed main jet with anadjustable idle. The idle circuit has a limiter cap toprevent over richening. The cap is locked onto theadjustment screw in a rich position, allowing only aleaner adjustment. The main is fixed on these, whichmeans that the main mixture limiter is non-functionalon Tecumseh built engines (diag. 4a).In compliance with E.P.A. and C.A.R.B. regulationsthe following procedure must be followed.NOTE: These caps can be removed for servicingof the carburetor. Follow these steps.1. Turn the caps clockwise until they hit the stops.2. Remove the caps with a pointed instrument

such as an awl.3. Then turn the screws in until softly seated, note

the number of turns. The screws must be reinstalledto this same static setting. Replacement of thecaps is required to maintain E.P.A. and C.A.R.B.emission compliance.

FIXED MAIN

(MIXTURE SCREWNOT FUNCTIONAL ONMOST TECUMSEHBUILT ENGINES)

IDLE SPEEDADJUSTMENTSCREW

IDLE MIXTURELIMIT SCREW

12

2-Cycle Engine Speed and Mixture Adjustments: TVS/TVXL840

Rotate sleeve clockwise to increase R.P.M., counterclockwise to decrease R.P.M.NOTE: The sleeve is serrated to rotate in a clockwise direction and must be raised using the sleeve tabs

before it can be rotated counterclockwise.To disassemble, remove choke shutter with needle-nose pliers; the vane assembly may then be removedfrom the carburetor.

9HORIZONTAL FIXED SPEED

PLASTIC AIR VANE GOVERNOR 10

BEND TAB TOADJUST RPM

INCREASE

DECREASE

Governor and Linkage for Air Vane

IDLE RPMADJUSTMENT

SCREW

HIGH SPEEDRPMADJUSTMENTSCREW

The HXL840 - 850 Series with variable speed controlhave the following adjustments. Idle speed is set atthe carburetor crack screw. High speed is set withthe screw shown above. Always check Microfichecard 30 or Parts Smart computer program forcorrect speed settings.

R.P.M. adjustment of fixed speed models is doneby bending the tab as shown.

HSK/HXL840-850

IDLE SPEEDADJUSTMENT

HIGH SPEEDADJUSTMENT

5HOLDINGSCREW

Linkage LocationTo aid in the proper reassembly of the governorlinkage, mark the linkage locations.

6

Static Governor AdjustmentTo adjust the static governor, loosen the holdingscrew, rotate the governor arm and slotted shaft inthe direction that will open the throttle to the wideopen position, and then re-tighten the holding screw.

VANE ASSEMBLY

STATIC GOVERNORADJUSTMENT SCREW

7

8

BEND TAB

TO ADJUST HIGH-SPEED ROTATECLOCKWISE TOINCREASECOUNTERCLOCKWISETO DECREASE

DECREASE

INCREASE

13

HORIZONTAL FIXED SPEED

15

VERTICAL ENGINEFIXED SPEED-REMOTE CONTROL

VERTICAL ENGINEVARIABLE SPEED-REMOTE CONTROL

HORIZONTAL FIXED SPEED(ALUMINUM AIR VANE GOVERNOR)

Governors and Linkage for Air Vane - continued

13

ADJUST RPM BYLOOSENING SCREW ANDSLIDING BRACKET

ADJUST RPM BYLOOSENING SCREW ANDSLIDING BRACKET

SPRING

IDLE RPMADJUSTMENTS

HIGH SPEED RPMADJUSTMENT

THIS HOLE NOTPRESENT ONALL MODELS

SPRINGVERTICAL ENGINEVARIABLE SPEED

MANUAL CONTROL

11

IDLE RPMADJUSTMENT

THIS HOLE NOTPRESENT ON ALLMODELS

SPRING

12

GOVERNORLINK

14

RPM ADJUSTMENT


SPRING

VERTICAL ENGINE FIXED SPEED 16


SPRING

HIGH SPEEDRPMADJUSTMENT

IDLEMIXTURE

HIGH SPEEDRPM ADJUSTMENTIDLE

MIXTURE

IDLE RPMADJUSTMENT

INCREASE

DECREASE

INCREASE

DECREASE

14

Static Governor AdjustmentsThe purpose of making a static governor adjustmentis to remove all free-play between the governorspool and the carburetor (see illustration). Any free-play here will result in hunting/surging or erraticrunning. After completing this procedure, alwaysre-check the engine speeds using the steps outlinedin the following pages.

To set the static governor, do the following:1. Be sure the engine is stopped or damage may

occur.2. If equipped with a throttle control, place the

throttle in the high speed position.3. Loosen the governor clamp or screw.4. Hold the governor arm and link in the W.O.T.

(wide open throttle) position, then rotate theshaft or shaft/clip assembly in the same direc-tion and tighten the screw.

5. If engine speed adjustments are needed, followthe steps described in following pages.

When assembling governor shaft into a flange or cover mounting boss, refer to this chart for exposed shaftlength.

Governor Shaft Pressed In Depth

Engine Model Exposed Shaft LengthECH 90 Mounting flange to topECV 100 1.319 - 1.334"H 30, 35 (33.502 - 33.883 mm)HS 40, 50LAV (all)LEV (all)OHH (all)OVRM (all)TNT 100, 120TVS (all)VLV (all)

TVM (all) Mounting flange to topV 50, 60, 70 1.581 - 1.596"VH 50, 60, 70 (25.806 - 26.314mm)

HH 100, 120 Mounting flange to topVH 100 1.016 - 1.036"

(25.806 - 26.314 mm)

Engine Model Exposed Shaft LengthH 50, 60, 70 Mounting flange to shoulderHH 60, 70 1.283 - 1.293"HHM 80 (32.588 - 32.842 mm)HM 70, 80, 100

OHV 11-17 Mounting flange to topOVM 120 1.350 - 1.365"OVXL 120, 125 (34.290 - 34.671 mm)

OHM 90-120 Mounting flange to topOHSK 90-130 1.085 - 1.100"

(27.559 - 27.940mm)

OH 120-180 Mounting flange to top1.00"(25.400mm)

TVT - V -Twin Mounting flange to top1.196 (3.969 mm)

SPRING

GOVERNORSPOOL

NO FREEPLAY

THROTTLECHOKE

WIDE OPENTHROTTLE

CLOSEDTHROTTLE

GOVERNORROD

15

* As of August 1992, all small frame engines, including VLV40-6.75, usea retainerless shaft. Service replacement shafts will be retainerlessfor all small frame and VLV engines.

Medium Frame VerticalModels: TVM125, 140, 170, 195, 220 - V50,60,70 -VH50,60,70

VLV*40, 50, 55, 60, 65, 66

Small Frame, Vertical and Horizontal*Models: LAV35,40,50 - H25,30,35 - HS40,50 - HSK - HSSK -TNT100,120 - ECH90 - TVS75,90,105,115,120 - OVRM ALL- ECV100,105,110,120

Retainerless Governor System for SmallFrames*

RETAININGRING

SPOOL

RETAININGRING

GEAR ASSY.(GOV.)

WASHER

SHAFT

SPOOL

SHAFT

WASHER

GEAR ASSY.(GOV.)

TYPE I SPOOL

IDLERGEAR

WASHER

GEAR ASSY.(GOV.)

RETAININGRING

TYPE II

WASHER

GEAR ASSY.(GOV.)

SHAFT

SPOOL

UPSETRETAINER

SHAFT

SPACER

WASHER

RETAININGRING

WASHER

SPOOL

RETAININGRING

GEAR ASSY.(GOV.)

* As of August 1992, all small frame engines, including VLV40-6.75, use a retainerless shaft. Service replacement shafts willbe retainerless for all small frame and VLV engines.

NOTE: Gear assembly must have .010 - .020 (.25 - .50 mm) endplay after shaft is installed into flange.

* As of August 1992, all small frame engines, including VLV40-6.75, usea retainerless shaft. Service replacement shafts will be retainerlessfor all small frame and VLV engines.

NOTE: Gear assembly must have .010 - .020 (.25 - .50 mm)end play after shaft is installed into flange.

UPSET ROLLED

.010 - .020 (.25-.50 mm)CLEARANCE

16

SHAFT

WASHER

BRACKET

SPOOL

RETAININGRING

GEARASSY.(GOV)

SCREWS

ROD ASSY.(GOV.)

SPOOL

WASHER

RETAININGRING

GEAR ASSY.(GOV.)

WASHER

SPACER

SHAFT

SPOOL

WASHER

RETAININGRING

GEAR ASSY.(GOV.)

WASHER

SPACER

SHAFT

NOTE; SPACERMAY BE PARTOF THE GEARASSEMBLY.

SPOOL

WASHER

GEAR &SHAFTASSY.(GOV.)

WASHER(CAPTURED UNDERGEAR)

Medium Frame HorizontalModels: HH60,70 - H50,60,70 - HM70,80,100 -HMSK

OVM120, OVXL120, 125 - OHV11-17

OHM120 - OHSK 80-130

OH120, 140, 160, 180

NOTE: On models OHV13.5-17, the spacer is cast as partof the governor gear with the washer placed below thegear assembly.

17

MAIN MIXTURESCREW

17

18

** NON-ADJUSTABLENO CHOKEPRIMER

* ADJUSTABLEMIXTURES, CHOKE

SMALL WIRE (DRILL BIT)

HOLE IN BRACKET

HOLE IN SPEEDCONTROL CHOKEACTUATING LEVER

HOLE IN CHOKELEVER

LOW SPEEDADJUSTMENT SCREW

IDLE MIXTURESCREW

Engine Speed and MixtureAdjustments3-5 H.P. Vertical Shaft Engines

NOTE: Starting and operating problems may existwhen engines are used at high elevations (over4,000 feet above sea level). In cases where a fixedmain carburetor is used, refer to Bulletin 110 forcorrection. Engines which are identified ascompliant with CARB (California Air ResourcesBoard) or EPA (US Environmental ProtectionAgency) regulations can NOT be changed fromtheir factory jetting unless specificallyauthorized.Before making any speed or carburetor adjustmentsbe sure to adjust the governor and control bracket.See Governor Section of the Booklet.To adjust the speed control bracket, determinewhether the carburetor is an adjustable type, thenproceed.Some carburetors may have a choke lever which isoperated by the speed control bracket. To adjust thespeed control bracket for full choke operation, loosenthe speed control bracket mounting bolts and movethe speed control lever to the high speed/full chokeposition. Next insert a small piece of wire throughthe hole in the speed control bracket, choke actuatinglever, and the choke lever (diag. 18). When all threeholes are aligned tighten the mounting bolts.Once the speed control bracket is adjusted, themain and idle fuel mixtures can be adjusted. Startthe engine and allow it to warm up to normal operatingtemperature (3 - 5 minutes). Set the speed controlto the HIGH or FAST position, then turn the mainmixture adjustment screw in (clockwise) slowlyuntil the engine begins to run erratic (lean). Note theposition of the screw. Now, turn the screw out(counterclockwise) until the engine begins to runerratic (rich). Turn the screw in (clockwise) midwaybetween these two positions. This will be the bestsetting.Set the speed control to the IDLE or SLOW position.Adjust the idle mixture screw following the sameprocedure used to adjust the main mixtureadjustment.NOTE: SOME CARBURETORS HAVE FIXEDMAIN JETS. THE ABSENCE OF THE ADJUSTINGSCREW INDICATES A FIXED JET AND NOADJUSTMENT IS NECESSARY.After adjusting the fuel mixtures, engine speeds canbe adjusted. The correct operating speeds arefound on Microfiche card 30 of the Tecumseh MasterParts Manual, or the computer parts look-up program(Part Smart). On engines with adjustable carburetors(diag. 19 and 20) the high speed adjustment will bein one of two places. The first location is on thespeed control lever (diag. 19).

SPEED CONTROLMOUNTING BOLTS

HIGH SPEEDADJUSTMENT SCREW

19

18

HIGH SPEEDADJUSTMENTSCREW


IDLEMIXTURESCREW

MAIN MIXTURE SCREW

COUNTERCLOCKWISETO INCREASE SPEED

CLOCKWISE TODECREASE SPEED

SPEED CONTROLMOUNTING BOLTS

20

Engine Speed and Mixture Adjustments - continued3-5 H.P. Vertical Shaft Engines

21



22

SPEED ADJUSTMENT TABBEND TO INCREASE SPEED


23

The second is on a bracket located between theblower housing and the speed control (diag. 20).Low speed is adjusted by the throttle crack screwon the carburetor (diag. 19 and 20).

It may be necessary to preset the carburetor mixturescrews.

Tecumseh CarburetorsEngine Model Main Pre-set Idle Pre-setAll models withfloat-type carburetors 1-1/2 turn 1 turnAll models withdiaphragm-typecarburetors 1 turn 1 turn

Some speed control brackets are adjusted byloosening the speed control bracket mounting boltsand sliding the bracket all the way to the right and re-tightening the mounting bolts (diag. 21). The highspeed adjustment screw is located on the speedcontrol lever (diag.22) Some carburetors are fixedspeed and are adjusted by bending the adjusting tabattached to the intake manifold (diag. 23).

After setting the engine speeds recheck the fuelmixtures, then recheck the engine speeds.

19

TNT 100 VERTICAL ENGINES

25

26

BEND CONTROLBRACKET TO SET

RPM

VERTICAL ENGINES

TVS 115 ENGINE WITH DUALSYSTEM CARBURETOR



HIGH SPEED RPMADJUSTMENTSCREW

GOVERNED / NON-GOVERNED IDLEWith the engine running at its lowest speed, set the governed idle at the designated R.P.M. by bending theidle R.P.M. tab. Next set the non-governed idle by pushing the bottom of the governor lever away from thecontrol brackets, so the throttle lever contacts the idle speed screw. Hold the lever in this position and turnthe idle adjustment screw clockwise to increase or counterclockwise to decrease engine idle speed. Thesetting on the carburetor screw should be set at 600 R.P.M. below the governed idle setting. This settingprevents the throttle plate from closing when going from high speed R.P.M. to low speed R.P.M. If improperlyadjusted, the engine could experience an over lean condition.

VERTICAL SHAFT ENGINES

28



27

HIGH SPEEDRPMADJUSTMENTSCREW

IDLE SPEEDCRACK SCREW

NOTE:ON REMOTE CONTROLTHIS WILL NOT BEPRESENT

LOW SPEED ADJUST

HIGH SPEED ADJUST

OVRM 29

Engine Speed and Mixture Adjustments - continued3-5 H.P. Vertical Shaft Engines

LOW SPEED TAB HIGH SPEED TAB

DECREASE

INCREASE

HIGH SPEEDPIN POSITION

TOOL(670326)

SNAP IN CONTROL 24

20



LONG BEND

SHORT BEND

GOVERNOR SPRING

TWIST COUNTERCLOCKWISE

TO DISCONNECT

30

VLV Governor and Linkage

Governor AdjustmentWith the engine stopped, loosen the screw holdingthe governor clamp and lever. Turn the clampclockwise, then push the governor lever (connectedto the throttle) to a full wide open throttle position.Hold the lever and clamp in this position and tightenthe screw.

Speed ControlsThis engine has an adjustable speed control. Neverexceed the manufacturer's recommended speeds.

NOTE:Governor adjustment screw will be a Torxhead (T-10) effective August 1, 1996 forE.C. Compliance.

Linkage InstallationThe solid link is always connected from the throttlelever on the carburetor to the lower hole on thegovernor lever. The shorter bend has to be towardthe governor. The governor extension spring isconnected with the spring end hooked into the upperhole of the governor lever and the extension endhooked through the speed control lever. To removethe governor spring, carefully twist the extensionend counterclockwise to unhook the extension springat the speed control lever. Do not bend or distort thegovernor extension spring (diag. 30).

HIGH SPEED ADJUSTMENT

COUNTERCLOCKWISE INCREASES SPEED

LOW SPEED ADJUSTMENT

COUNTERCLOCKWISE INCREASES SPEED

31

FIXED SPEED

Fixed SpeedHigh speed governor adjustment is accomplishedby bending a tab to increase and decrease engineR.P.M. Effective August 1997 (diag. 31a).

31A

TOOL 670326

HIGH SPEEDADJUSTMENT

21

MAIN MIXTURESCREW

MAIN MIXTURESCREW

32

33

34

SMALL PIECE OF WIRE

HOLE IN CONTROL BRACKET

MOUNTINGBOLTS

HOLE INCHOKEACTUATINGLEVER

HOLE IN CHOKE LEVER

HIGH SPEEDADJUSTMENT SCREW

THROTTLECRACKSCREW

IDLE MIXTURESCREW

GOVERNORADJUSTINGLEVER



MOVE THE CONTROLLEVER IN THE HIGHSPEED POSITION

THROTTLE CRACK SCREW

IDLE

MIXTURESCREW

Engine Speed and MixtureAdjustments5-15 HP Vertical Shaft Engines

The first step is adjusting the speed control bracketfor full choke operation. Loosen the two speedcontrol bracket mounting bolts and move the controllever to the full high speed/full choke position. Inserta piece of wire through the hole in the speed controlbracket, the choke actuating lever, and the chokelever (diag. 32). When all three holes are in alignmentretighten the speed control bracket mounting bolts.

The second step is adjusting the main and idlefuel mixtures. Start the engine and allow it to warmup to normal operating temperature (3 - 5 minutes).Set the speed controls to the HIGH or FAST position,then turn the main mixture adjustment screw in(clockwise) slowly until the engine begins to runerratic (lean). Note the position of the screw. Now,turn the screw out (counterclockwise) until theengine begins to run erratic (rich). Turn the screwin (clockwise) midway between these two positions.This will be the best setting.Set the speed control to the IDLE or SLOW position.Adjust the idle mixture screw following the sameprocedure used to adjust the main mixture adjustmentscrew.NOTE: SOME CARBURETORS HAVE FIXEDMAIN JETS. THE ABSENCE OF THE ADJUSTINGSCREW INDICATES A FIXED JET AND NOADJUSTMENT IS NECESSARY.

The third step is setting engine speeds. Thecorrect engine operating speeds are listed on card30 of the Tecumseh Master parts manual microfiche,or the computer parts look-up program (Part Smartor Plus One). The most common speed controlbracket (diag. 33) has the high speed adjustmentscrew located on the speed control lever. The lowspeed adjustment screw is the throttle crack screwon the carburetor body. Another common speedcontrol is the governor override system (diag. 34).This system has a similar speed control bracketalong with a governor adjustment lever which isattached to the engine block. Both the high speedand low speed adjustment screws are located onthe governor adjusting lever.

22



To adjust high speed on an up/down control (diag.35)bend the adjustment tab. Low speed is adjusted bya screw at the bottom of the control bracket. Boththe governor override system and the up/downspeed control have a governed idle. On these systemsit is important to also adjust the throttle crack screw.To adjust the throttle crack screw use your finger tohold the throttle shutter tight against the throttlecrack screw and adjust the engine speed toapproximately 600 R.P.M. less than therecommended low speed.After setting the engine speeds recheck the fuelmixtures and double check the engine speeds.NOTE: Not all engines have fully adjustable

carburetors.It may be necessary to preset the carburetor mixturescrews.

Tecumseh CarburetorsEngine Model Main Pre-set Idle Pre-setAll models withfloat-type carburetors 1-1/2 turn 1 turnAll codels withdiaphragm-typecarburetors 1 turn 1 turn

IDLE MIXTURESCREW

THROTTLE CRACKSCREW

MAIN MIXTURESCREW

Engine Speed and Mixture Adjustments - continued2.5-17.5 HP Vertical Shaft Engines

35

HIGH SPEED ADJUSTMENT TAB

LOW SPEEDADJUSTMENTSCREW

CHOKEHOOKUP

TOOL #670326

ALIGNMENTHOLE

HIGH SPEEDADJUSTMENTTABTHROTTLELINK HOOKUP

GOVERNEDIDLE SPEEDSCREW

CHOKE LEVERAIR GAP(.040 - .070")(1.0 - 1.8 mm)BEND TAB TOADJUST

The idle speed is adjusted by turning the idle speed screw clockwise to increase engine R.P.M. andcounterclockwise to decrease R.P.M. Use tool part # 670326 to adjust the high speed engine R.P.M. Placethe slotted end of the tool onto the adjustment tab and bend the tab to the left (toward the spark plug end)to increase engine R.P.M. (diag. 36).NOTE: Be sure that the throttle cable has full travel from wide open throttle to full choke. Hard Startingcould result if the cable is not properly adjusted to allow for full choke.

TVXL220, OHV 11-17 STYLE SPEED CONTROL 36

IDLE SPEEDCRACKSCREW

IDLE MIXTURESCREW

23

Engine Speed and Mixture Adjustments - continued

OVM/OVXL,TVM 170, 195 & 220

Governor Override System for TVM170, 195 and 220 Engines (diag. 41)This system will be found starting on 1985 production models and will not retrofit onto older engines. It isdesigned to allow the governor to regulate the low and high speeds of the engine. The high speed is adjustedat the top screw of the override lever; to increase R.P.M. turn the screw out (counterclockwise), to decreaseR.P.M. turn the screw in (clockwise). The low speed is adjusted at the bottom screw of the override lever;to increase R.P.M. turn the screw in or clockwise, to decrease R.P.M. turn the screw out or counterclockwise(diag. 41).

STANDARD TVM ENGINE WITHOUTGOVERNOR OVERRIDE 40

MAIN MIXTURESCREW

GOVERNOR ADJUSTINGSCREW (LOW SPEED)

HIGH SPEED

41

LOW SPEED ADJUST

HIGH SPEED ADJUST

OVRM 3837OVRM SNAP IN CONTROL

LOW SPEED TAB HIGH SPEED TABHIGH SPEEDPIN POSITION

DECREASE

INCREASE

NOTE: ON REMOTECONTROL THISWILL NOTBE PRESENT

OVRM 39

SPEED CHANGESAPPROXIMATELY200 RPM PER SLOT

OHV 11-17

24

SMALL FRAME GOVERNED IDLE HORIZONTAL MEDIUM FRAME

CONSTANT SPEED APPLICATIONS

LIGHTWEIGHT R.V. TYPE

44 45

46 47HORIZONTAL MEDIUM FRAME



HIGH SPEED RPM ADJUSTMENT SCREWIDLE SPEED CRACK SCREW


IDLE MIXTURESCREW

MAINMIXTURE SCREW

IDLE SPEED CRACK SCREW

HIGH SPEED RPMADJUSTMENT SCREW


HIGH SPEED RPM ADJUSTMENT SCREW

IDLE MIXTURE SCREW

NOTE: Since 1996, all speed adjustment screws will have a torx head.


43

IDLEMIXTURE

MAINMIXTURE

Engine Speed and Mixture Adjustments -Horizontal Shaft Engines

42



HORIZONTAL LIGHTWEIGHT

HM / OHM

25

INCREASE DECREASE

Horizontal Shaft Engines - continued

53OHH RV CONTROL

GOVERNOR SPRINGGOVERNED IDLE LINK

51OHH REMOTE & MANUAL

49

OHH FIXED SPEED50

WINTERAPPLICATIONCONTROL

HIGH SPEEDADJUSTMENT BEND TO ADJUST SPEED

DECREASE INCREASE

GOVERNEDIDLE LINKANDADJUSTMENT

HIGH SPEED ADJUST

OH / OHSK CONTROL

OHSK / OHM CONTROL

GOVERNEDHIGH SPEEDADJUST

BEND

GOVERNEDHIGH SPEEDADJUST

GOVERNED IDLE TAB

GOVERNED IDLE SCREW

T-10 (TORX)THROTTLE CRACK SCREW

T-10 (TORX)THROTTLE CRACKSCREW

CORRECT BUSHINGINSTALLATION DEEPSIDEHERE52

48MEDIUM FRAME


HIGH SPEED RPM ADJUSTMENT SCREW

54

HM80-100 SERIES

OHH FIXED SPEED

TURN NUT TOADJUST SPEED

26

55

56

Governor Adjustment for Horizontal EnginesMove the remote controls to the RUNposition.Loosen Screw "A".Pivot plate "B" counterclockwise and hold.Move lever "C" to left.Tighten screw "A" securely.

When the governor is properly set the carburetorthrottle lever will be in a wide open position when thecontrols are set for starting.The governor spring is to be anchored in the bottomcenter hole (D) of plate "B". Do not stretch or cut thegovernor spring. Above adjustments will correctany variations in governor control (diag. 55).

1. Setting Variable Speed Adjusting Screw.Before attaching the bowden wire, set the enginefor maximum R.P.M. (See Mfg. specifications)with engine running. Use a good tachometer.Move lever "A" clockwise until lower end strikesthe adjusting screw at position "1" (diag. 56).Loosen lock nut on adjusting screw and turn in todecrease R.P.M. Turn out to increase R.P.M.CAUTION: DO NOT EXCEED

RECOMMENDED R.P.M.

2. Adjusting Fixed Speed. The fixed speed ad-justing screw is the optional position "2". Adjustit by starting the engine, then loosening thelocknut. Turn the screw in to increase R.P.M.and out to decrease R.P.M.

NOTE: The TVT-control system is shown only inthe 696325 Technician's manual.

IDLE

FAST

(CW) HOLE "B"

BOWDENWIRE CLAMP"B"

HOLE "C"

BOWDENWIRECLAMP"C"

(CW)

PIVOT

"A"LEVER

Engine Speed Adjustments - 8-18 HP, Cast Iron

VARIABLESPEED

GOVERNOR SPRING

MOVE TO"RUN"POSITION

GOVERNORADJUSTINGSCREWS

PIVOT POINT

TURN CCW

"C"

"A""B"

"D"

FIXEDSPEED

Adjustingscrew fixedspeedposition "2"optional

Adjustingscrew variablespeed position"1" standard

(LOW)

(HIGH)

(HIGH)

(LOW)

27

Low Oil Shutdown SwitchesCheck the LOS switch while it is in the engine. Theengine must be level, and the oil level at the fullmark. Place the speed control in the run position.Remove the spark plug wire from the spark plug.Install a gap type tester connected to the spark plugwire and a good engine ground. Spin the engineover using the electric or recoil starter. A bright bluespark should be seen at the tester. If not, removethe blower housing and disconnect the LOS leadfrom the ignition module. Reinstall the blower hous-ing and spin the engine over. If spark occurs now,replace the LOS switch. If no spark is seen, replacethe ignition module (diag. 57).

57

58

59

Switches, Sensors, and Solenoids

Low Oil Shutdown Indicator LightIf equipped, the indicator light will flash if the oil levelis at or below the add mark when the engine is turnedover while attempting to start. Test by turning theengine over with the oil level below the add mark. Ifthe indicator light does not flash, replace the indicatorlight (diag. 58).

Low Oil Pressure SensorTest the sensor on a running engine using anohmmeter or continuity tester with one test leadconnected to the sensor terminal and the other to anengine ground. An open circuit should be found withthe engine running and continuity should exist whenthe engine is shut off. If continuity is found or the oilpressure indicator is on at low engine R.P.M.'s,remove the sensor and install a master oil pressuregauge. The oil pressure of a running engine shouldbe 7 p.s.i. (.500 bar) or higher, if lower an internalengine problem exists (diag. 59).

OIL SHUTDOWN SWITCH

TO IGNITION

TO LOW OILSENSOR

GREENIDENTIFICATIONMARK

28

Low Oil SensorThis sensor must use a #194 bulb, resistance of thebulb MUST be .27 ampere in series with the sensorfor proper operation and to prevent sensor damage.Remove the sensor from the engine and attach theelectrical plug. Attach a jumper lead from an engineground to the threaded portion of the sensor. Placethe keyswitch in the run position. The indicator lightshould come on with the tip of the sensor in air(uncovered) and go off when oil covers the sensortip. The response time of the sensor is between 5and 15 seconds with 13 volts D.C. at the battery.Lower battery voltage will result in a longer responsetime. Use teflon-type pipe sealant on the sensorthreads to prevent oil leakage when reinstalling(diag. 60).

60

61

DOUBLESINGLE

Fuel Shutdown SolenoidsIf the engine is running, the solenoid can be checkedby removing the electrical plug-in at the base of thesolenoid. Almost immediately the engine shouldshutdown, if not replace the solenoid (diag. 61).

Test the solenoid off the carburetor by applying 12volt D.C. from the battery positive terminal to asolenoid terminal. Connect a jumper wire from themetal housing (or other terminal) to a negativebattery terminal. The plunger should retract the fulltravel distance. Disconnect the negative jumper leadand the plunger should return to the extendedposition. Replace if necessary (diag. 61).

Switches, Sensors, and Solenoids - continued

62

On/Off Switches

Engine On/Off Rocker Switch

63

Lighted Engine On/Off Rocker Switch w/Low Oil Shutdown

TERMINAL

SPACER

2 TERMINALS 3 TERMINALS

23L

2TO IGNITION

LTO LOW OILSENSOR

TOGROUND 3

29

Wiring

CONDITION. All wiring must be fully insulated between connection points, securely fastened and free offoreign material (such as rust and corrosion) at the connection points. This is especially important in theuse of batteries where much of the potential may be lost due to loose connections or corrosion. Rememberto check the insulation on the wire. All it takes is a pin hole for a wire to "ground out" on the engine or frame.This is of special concern when moisture or water is present. This may cause the engine to run erraticallyor be impossible to start.

WIRE GAUGE: Proper thickness of wire is necessary in all electrical circuits. Wire diameter is measuredin increments of gauge numbers. The larger the number, the smaller the diameter of the wire. The smallerthe number, the larger the diameter of the wire.

1. Starter circuit wiring must be rated at #6 or lower gauge number.2. Charging circuit wiring must be rated at #16 or lower gauge number. (20 amp system requires #14

or lower gauge number).3. Magneto circuit wiring (ground circuit) must be rated at #18 or lower gauge number.

Color Codes

Tecumseh Products Company standard wiring color codes effective August, 1992 are as follows:Code ProductYellow - Alternator A.C. LeadsRed - Alternator D.C. + LeadsBrown - Alternator D.C. - LeadsBlack - Alternator Ground Leads, Battery Ground LeadsOrange - 12 Volt Starter B + LeadsDark Green - Ignition Shut-Off Leads

NOTE: Prior to August 1992, wire codes changed according to model and specification numbers.

AmmetersAn ammeter is used to measure the rate of current flow from the alternating system to the battery. If nocurrent flow is indicated by the ammeter, remove the ammeter from the circuit and check all othercomponents in the system. Use the ohmmeter to check continuity across the ammeter. If no continuityexists, replace the ammeter.

30

64

65

GROUNDED SOLENOID

START POSITIONCIRCUIT CLOSED

RUNNING ANDSTOP POSITION

INSULATED SOLENOID

START POSITIONCIRCUIT CLOSED

RUNNING AND STOPPOSITION CIRCUIT

DiodesIn order to charge a battery it is necessary to convert alternating current (A.C.) to direct current (D.C.) Thisis accomplished by using a diode or rectifier. Using a single diode will make use of one half of the A.C. signaland is known as HALF WAVE RECTIFICATION. This is acceptable in certain applications. In certainsituations it is necessary to make use of the entire A.C. signal. To accomplish this we use multiple diodesin a bridge configuration which produces FULL WAVE RECTIFICATION.

SolenoidsA solenoid is a heavy duty switching mechanismused to handle large amounts of current. It consistsof a heavy strip of metal activated by an electromagnet.The metal strip connects two contact points and"makes" or "breaks" the electric circuit. Becausethe metal strip is heavier than most switch contacts,it does not pit or burn away as lighter switch contactswill.

To test a grounded solenoid, connect positive (+)solenoid terminal (next to solenoid ground) to thepositive (+) battery terminal. Connect negative ground(-) terminal of the solenoid to the negative (-) batteryterminal. If solenoid is in good condition, the plungerwill "snap" and close the main contacts (diag. 64).

NOTE:With a grounded solenoid, battery B+ issupplied to activate. With insulated solenoid,battery B- is supplied to activate.

To test an insulated solenoid, connect the terminalmarked "B" to the positive (+) battery terminal.Connect terminal marked "G" to the negative (-)battery terminal. If the solenoid is in good condition,the plugger will "snap" and close the main contacts.

ANODE CATHODE

BAND OR OTHERMARKING INDICATESCATHODE END

A.C. INPUT

(+) VOLTAGE (D.C.)

The full wave rectifier makes use of theentire A.C. signal, converting it to D.C.

DIRECTION OR FLOW OF CURRENT

31

Key SwitchesSwitches are the common point on the vehicle where most of the wiring centrally comes together. Thereare many varieties of switches available. Replace damaged or failed switches according to the equipmentmanufacturer's specifications. NEVER substitute an automotive switch for a switch replacement on a smallengine application, or a switch from an engine with a battery ignition.

The more common switches are shown below:

IMPORTANCE OF USING CORRECT SWITCHSome switches are too small to take the continual"make" and "break" without burning the electricalcontacts. This is when it is advisable to install therecommended manufacturers switch.***NOTE: WARRANTY IS VOID FOR THE

ENGINE COMPONENTS BEINGBURNED OUT DUE TO A FAULTYSWITCH.

EXAMPLE:

E. F.

A. B. C. D.

32

Con

tinui

ty w

/ ke

y

in s

tart

po

sitio

nC

ontin

uity

w /

key

in o

ff p

osi

tion

NO

Con

tinui

ty in

any

key

po

sitio

nC

ontin

uity

w /

key

in r

un p

osi

tion

Con

tinui

ty w

/ ke

y

in s

tart

po

sitio

nC

ontin

uity

w /

key

in o

ff p

osi

tion

NO

Con

tinui

ty in

any

key

po

sitio

nC

ontin

uity

w /

key

in r

un p

osi

tion

Continuity Check for Switches

NOTE: This is only a generic test, manufacturer's may differ in switch terminals and functions.

Switch D (metal case)Connect Ohmmeter Leads to:

S & B XM & Switch Case X

M & B XM & S X

Switch EConnect Ohmmeter Leads to:

M & S XM & B XM & G XM & L XS & B XS & G XS & L XG & L XB & G XB & L X X

Switch FConnect Ohmmeter Leads to:

A & G XA & B XA & M XA & S XG & B XG & M XG & S XB & M XB & S XM & S X

Switch AConnect Ohmmeter Leads to:

S & G XM & G XM & S X

Switch B (metal case)Connect Ohmmeter Leads to:

S & G XS & B X

S & A, S & metal case XM & B X

M & A, M & metal case XB & A X

B & metal case XA & metal case X

with 5th terminalR & S, R & M XR & B, R & A X

R & metal case X

Switch CConnect Ohmmeter Leads to:

A & S XA & M, A & G (3) X

A & R, A & B XS & M, S & R, S & G (3) X

S & B XM & R, M & B X

M & G (3) XR & G (3) X

R & B XB & G (3) X

33

35493

611111

34960

34990

3 Amp A.C.

610981

3 Amp A.C.

611095

ENGINE

ALTERNATORSHAFT

CENTERINGTUBE

RECOILSTARTER

ADD-ONALTERNATOR

SELF-TAPPINGSCREWS

A.C.CONNECTOR

D.C.CONNECTOR

1 AMP (18 WATT) A.C. - ADD-ON ALTERNATOR611077 (Alternator Only)350 Milliamp

18 Watt A.C. Lighting

Red

Red

Black

Red

Brown

Yellow

Red

Green

Black

Yellow

Green

Green

610968

Red Green

3 Amp D.C.

Yellow wireunder sleeve

Red

Yellow

Yellow - Alternator A.C. LeadsRed - Alternator D.C. (+) LeadsBrown - Alternator D.C. (-) Leads

Black - Alternator Ground/Battery GroundOrange - 12 Volt Starter (+) LeadsDark Green - Ignition Shut-off Leads

34

2 and 3 Amp D.C.

611116 (3 Amp)

3 Amp D.C. - 5 Amp A.C.

7 Amp D.C.

610818* Uses regulator/rectifier 610749

7 Amp D.C.

3 Amp D.C.

611113

5 Amp D.C.

* Uses regulator / rectifier 611175A

610975

* Uses regulator / rectifier 610938

Red

Diode

Red

Red

Diode

GreenGreen

Red

Yellow

RedYellow

611176

Yellow

Yellow

Green

Red

Green

Yellow

Red

Red Yellow

Diode

611104

Yellow

3 Amp

2 Amp(requires optional flywheel)

Yellow - Alternator A.C. LeadsRed - Alternator D.C. (+) LeadsBrown - Alternator D.C. (-) Leads

Black - Alternator Ground/Battery GroundOrange - 12 Volt Starter (+) LeadsDark Green - Ignition Shut-off Leads

Charging SystemCharging System - continued

35

* Uses regulator/rectifier 610749

10 Amp Alternator

20 Amp Alternator

* Uses regulator/rectifier 610996 or 610907A; depending on specnumber an open circuit D.C. voltage check cannot be made.

610902

611097

* Uses regulator/rectifier 611098; an open circuit D.C. voltagecheck cannot be made.

7 Amp D.C.

Charging System - continued

Red

Green

Yellow

Red

Yellow

Green

YellowGreen

Yellow

Black

611159

Yellow

Green

10 Amp D.C.610761

Yellow

Green

Yellow

Black

Yellow

Green

611256

7 Amp D.C.

Red

Green

Yellow

RedYellow

Green

YellowYellow

Regulator/Rectifiers

7 Amp610938

Yellow

Red

YellowYellow

Green

Yellow

Green

Red

AC

DC DC

AC

DC

AC

DC AC

Yellow - Alternator A.C. LeadsRed - Alternator D.C. (+) Leads

Brown - Alternator D.C. (-) LeadsBlack - Alternator Ground/Battery Ground

Orange - 12 Volt Starter (+) LeadsDark Green - Ignition Shut-off Leads

7 Amp611098

5 Amp, 7 Amp611175

7 Amp, 10 Amp610749

20 Amp610996

610907A

12 Amp D.C.

12 Amp611274

5 Amp, 7 Amp611175A

Green

Yellow

Green

Yellow

Red

Red Yellow

Yellow

YellowDot

36

Testing ProceduresD.C. Charging AdaptorRectifier Bridge Check With Ohmmeter for D.C.Adaptor

Continuity should exist during one of the two followingtests. No continuity should exist while performingthe opposite test.

If continuity exists during both tests, or if no continuityexists during both tests, the D.C. adaptor is defective.

TEST NO. 1 - Connect negative probe of meter tored output lead. Connect positive probe of meter toboth A.C. terminals and black output lead (diag. 66).

2000 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 10.5 Volts A.C.3600 R.P.M. - 12.0 Volts A.C.

CAUTION: When testing Alternator/Charging System:DO NOT disconnect positive lead(s) from the battery while the engine is running. With the enginestopped, disconnect lead(s), then perform test and stop engine before re-connecting. Connectingor disconnecting while the engine is running will send a voltage surge through the regulator, causingdamage.

TEST NO. 2 - Connect positive probe of meter to red output lead. Connect negative probe of meter to bothA.C. terminals and black output lead.

Connect negative probe of meter to black output lead. Connect positive probe of meter to both A.C.terminals and red output lead.

If the D.C. adaptor is not defective and a known good battery fails to hold a charge, then perform an A.C.output voltage test.

NOTE: PRIOR TO AUGUST 1992, THE BLACK WIRE WAS BROWN.

CHECKING THE SYSTEM: To check the system, disconnect the D.C. adaptor from the add-on alternator.Connect a No. 4414, 18 watt bulb in line with each terminal in the alternator. Start engine and test circuitusing an A.C. voltmeter as shown.

With the engine running, minimum A.C. voltage values across the bulb should be:2000 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 10.5 Volts A.C.3600 R.P.M. - 12.0 Volts A.C.

If the minimum values are noted, alternator is okay. If the minimum values are not noted, the alternator orA.C. connector is defective.

66

Red

Black

A.C. TERMINALS

Red

Black

#4414BULB

37

BATTERY GROUND (BLACK)ELECTRIC STARTERLEAD (ORANGE)

BLACKRED

(-) ENGINE GROUND

(+) POSITIVE LEAD

MAGNETO GROUND(GREEN) D.C. OUTPUT

LEAD (RED)

67

YELLOW

#4414 BULB

ENGINE

68

350 Milliamp Charging System

CHECKING THE SYSTEM: The battery must be inthe circuit to perform the test properly. Set thevoltmeter to the 0-20 D.C. volt scale. Connect avoltmeter across the battery. The voltmeter shouldread battery voltage. Start the engine. With theengine running, there should be an increase in thevoltage reading. If there is no change in the voltagereading, the alternator is defective and should bereplaced (diag. 67).

18 Watt A.C. Lighting Alternator ModelsH35, HS & HSSK 40-50, HM & HMSK 70-80-100

CHECKING THE SYSTEM: To check the system,disconnect the plug from the rest of the lightingsystem. Connect a wire lead from the single pinconnector coming out of the engine to one terminalof a No. 4414, 18 watt bulb. Connect another wire tothe remaining terminal of the bulb and run it to a goodground on the engine. Start the engine and test thecircuit using the A.C. voltmeter as shown (diag. 68).With the engine running the minimum A.C. voltageacross the bulb should be:2000 R.P.M. - 6.0 Volts A.C.3000 R.P.M. - 8.5 Volts A.C.3600 R.P.M. - 10.0 Volts A.C.If minimum values are noted, the alternator is okay.If less than the minimum values, the alternator isdefective.

38

35 Watt A.C.Before making any exterior tests, check for aninoperative switch, shorted wires and burned outheadlight and/or stop tail light. To check out thealternator, check the A.C. lead to ground at eachyellow wire (diag. 69).

With engine running, minimum values should read:2500 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 9.5 Volts A.C.3300 R.P.M. - 10.5 Volts A.C.3600 R.P.M. - 11.5 Volts A.C.

If the above minimum readings are noted, thealternator is okay. Check for defective lights, wiringor switches, if less than the above readings, thealternator is defective.NOTE: ON OLDER POINT IGNITION SYSTEMS,

THE A.C. OUTPUT LEADS ARE BLACKAND RED.

YELLOW

YELLOWA.C. GREEN

IGNITIONSTOP

69

#4414 BULB

Yellow

Yellow

1 Amp (18 Watt) Add-on Alternator

CHECKING THE SYSTEM: To check the system,disconnect the plug from the rest of the lightingsystem. Connect a No. 4414, 18 watt bulb in line witheach terminal in the plug. Start the engine and testthe circuit using a voltmeter as shown (diag. 70).

With the engine running the minimum A.C. voltagevalues across the bulb should be:

2000 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 10.5 Volts A.C.3600 R.P.M. - 12.0 Volts A.C.

If minimum values are noted, the alternator is okay.If the minimum values are not noted, the alternatoror A.C. connector is defective.

70

39

2.5 Amp D.C., 35 Watt LightingIf output is below standard listed, pull back protectivecoating in front of the diode and check A.C. output.If A.C. is good check each diode it services asrequired (diag. 71).

D.C. value (+) or (-); check both sides of A.C.outputs.

R.P.M. D.C. Volts R.P.M. Volts A.C.2500 - 8.0 Volts D.C. 2500 - 18 Volts A.C.3000 - 9.5 Volts D.C. 3000 - 22 Volts A.C.3300 - 10.5 Volts D.C. 3600 - 26 Volts A.C.3600 - 11.5 Volts D.C.

NOTE: These minimum numbers should beobtained by your meter and will often behigher.

D.C.TWO DIODES

RED

D.C. NEGATIVEOUTPUT LEAD(BROWN D.C.)

D.C. POSITIVEOUTPUT LEAD(RED D.C.)

A.C.D.C.

71

2 and 3 Amp DC Alternator System - Diodein Harness Models: H30-35, HS40, H50-60,HH50-60, HM70-80-100, HMSK, HHM80,HSK, HSSK, Rotary Mower Engines

This system has a diode included in the red wirewhich converts the alternating current (A.C.) todirect current. The direct current (D.C.) is used toprovide a trickle charge for the battery. The leadsfrom the alternator and the type of connector mayvary, but the output readings will be the same.

CHECKING THE SYSTEM: Remove the fuse (ifequipped) from the fuse holder and check the fuseto make certain it is good. If faulty, replace with a six(6) AMP fuse.

To check D.C. output, separate the connectors atthe engine. Place the probe (+) in the red wire leadconnector. Ground the other probe to the engine(diag. 72).

With the engine running the minimum values shouldread:

2500 R.P.M. - 8.0 Volts D.C.3000 R.P.M. - 9.5 Volts D.C.3300 R.P.M. -10.5 Volts D.C.3600 R.P.M. -11.5 Volts D.C.

If these minimum readings are noted, the system isokay. Check for bad battery, ammeter, wiring, etc.

73

Red

Green

GROUNDPROBE (+)

Red

Green

DIODE

PROBE (+)

72

(Continued on Next Page)

40

If less than the above readings, proceed in making an A.C. output check by pulling back the protectivecoating from the fuse holder and diode. Using an A.C. voltmeter, check voltage from a point between theengine and the diode as shown in the diagram (diag. 73).With the engine running the minimum values should read:

2500 R.P.M. - 18.0 Volts A.C.3000 R.P.M. - 22.0 Volts A.C.3300 R.P.M. - 24.0 Volts A.C.3600 R.P.M. - 26.0 Volts A.C.

If low or no voltage is experienced, replace the alternator. If the alternator puts out the minimum A.C. voltage,replace the diode.

When replacing the diode in the rectifier panel,locate the undercut on one end of the diode andmatch it to the detent on terminal clip of the rectifierpanel.

Test the D.C. output of the rectifier panel as follows:

Disconnect the battery lead from the terminal of therectifier panel. Use a D.C. voltmeter probe on the +battery terminal (diag. 75). Connect negative lead toengine ground.

Minimum values should read:2500 R.P.M. - 12.0 Volts D.C.3000 R.P.M. - 14.0 Volts D.C.3300 R.P.M. - 16.0 Volts D.C.3600 R.P.M. - 18.0 Volts D.C.If these minimum readings are noted, the system isokay. Check for bad battery, ammeter, wiring, etc.If reading is less, proceed to make an A.C. outputcheck. With the battery lead disconnected fromrectifier panel, probe the A.C. terminals with thevoltmeter on the A.C. scale (diag. 76).

74

75

+-

+ -TO ENGINEGROUND

FUSE

PROBE

D.C. VOLTMETERGreen

Yellow

Yellow

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 anda fuse for overload protection. The rectifier panel does not regulate the output of this system.

CHECKING THE SYSTEM: Check the fuse to determine if it is good. A continuity light or ohmmeter candetect a faulty fuse. Replace with a six (6) amp fuse if necessary. Determine if the diodes are functioningproperly. A continuity light may be used to check diodes (diag. 74).


41

Minimum values should read:2500 R.P.M. - 24.0 Volts A.C.3000 R.P.M. - 29.0 Volts A.C.3300 R.P.M. - 32.0 Volts A.C.3600 R.P.M. - 35.0 Volts A.C.

If less than above output, generating coil assemblyis defective.

NOTE: If there is no regulator in this system. Thetotal output of the two diodes is three (3)AMPS. If the battery is overcharging (boilingand bubbling), reduce the D.C. input byone-half by removing one of the diodes.

76

RECTIFIER PANELMOUNTED ONENGINE

A.C.VOLTMETER

FUSE

3 Amp D.C. 5 Amp A.C. Alternator Models OVM/OVXL 12.5, OHV12.5-17.0

This unit combines a 3 Amp D.C. system used tocharge a battery and a 5 Amp A.C. system used forlighting. Located in the red wire of the harness is adiode which converts the alternating current todirect current for charging the battery. The yellowwire provides the A.C. voltage for the lighting circuit.A wire harness (part# 36588) may be added to the3 Amp D.C./5 Amp A.C. charging system to poweran electric clutch without the use of a battery. Testthe diode in the harness by doing a continuity test(diag. 77).Replace the diode if continuity exists after reversingtester leads or if no continuity is found.

CHECKING THE SYSTEM: To check the system,disconnect the plug and measure the D.C. voltageat the red wire terminal (diag. 75). Measure the A.C.voltage at the yellow wire terminal. With the enginerunning the minimum values should be:

77

5 AMP A.C.

3 AMP D.C.RED LEAD DIODE

BLACK LEAD


42

MODELS OVM/OVXL/OHV3 Amp D.C. (Red wire)2500 R.P.M. - 8.0 Volts D.C.3000 R.P.M. - 11.0 Volts D.C.3600 R.P.M. - 13.0 Volts D.C.

5 Amp A.C. (Yellow wire)2500 R.P.M. - 8.5 Volts A.C.3000 R.P.M. - 11.0 Volts A.C.3600 R.P.M. - 13.0 Volts A.C.

MODELS OHV 13.5 - 17.0 (3/5 Amp split)3 Amp D.C. (Red wire)2500 R.P.M. - 6.5 Volts D.C.3000 R.P.M. - 9.0 Volts D.C.3600 R.P.M. - 11.0 Volts D.C.

5 Amp A.C. (Yellow wire)2500 R.P.M. - 15.0 Volts A.C.3000 R.P.M. - 18.0 Volts A.C.3600 R.P.M. - 22.0 Volts A.C.

If the above minimum values are noted, the systemis okay. Check for defective lights, wiring orswitches. If less than above values are noted, pullback the protective shrink tubing from the diode.Using an A.C. voltmeter, check the voltage betweenthe alternator and diode as shown (diag. 79). If lowor no voltage is experienced, replace the alternator.

75

80

79

DIODE

Red

D.C.D.C.

Yellow

Red

A.C.A.C.

DIODE

A.C.

DIODE

Yellow


43

81

Yellow

Red

DIODE

A.C.

DIODE

Red

D.C.D.C.

82

Yellow

Models OVM/OVXL/OHV(Read between Engine and Diode, diag. 81 &82)With the engine running the minimum values shouldread:2500 R.P.M. - 20.0 Volts A.C.3000 R.P.M. - 25.0 Volts A.C.3300 R.P.M. - 26.5 Volts A.C.3600 R.P.M. - 29.0 Volts A.C.

Models OHV13.5-17.0(Read between Engine and Diode)2500 R.P.M. - 17.0 Volts A.C.3000 R.P.M. - 21.0 Volts A.C.3600 R.P.M. - 24.5 Volts A.C.If low or no voltage is experienced, replace thealternator. If the alternator puts out the minimumA.C. voltage, replace the diode.

3 Amp D.C. 5 Amp A.C. Alternator Models: H & HSK 50-60, HH50-60, HM & HMSK 70-80-90-100, TVM125-140-170-195-220, TVXL195-220

This unit combines a 3 Amp D.C. system used to charge a battery and a 5 Amp A.C. system used for lighting.Located in the red wire of the harness is a diode which converts the alternating current to direct current forcharging the battery. The yellow wire provides the A.C. voltage for the lighting circuit.

CHECKING THE SYSTEM: To check the system,disconnect the plug and measure the D.C. voltageat the red wire terminal (diag. 82). Measure the A.C.voltage at the yellow wire terminal. With the enginerunning the minimum values should be:

3 Amp D.C.2500 R.P.M. - 8.0 Volts D.C.3000 R.P.M. - 11.0 Volts D.C.3600 R.P.M. - 13.0 Volts D.C.

5 Amp A.C.2500 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 11.0 Volts A.C.3600 R.P.M. - 13.0 Volts A.C.

If the above minimum values are noted, system isokay. Check for defective lights, wiring or switches.If less than above values are noted, pull back theprotective shrink tubing from the diode. Using anA.C. voltmeter, check the voltage between the alter-nator and diode as shown (diag.83).


44

All Models

With the engine running the minimum values shouldread:2500 R.P.M. - 20.0 Volts A.C.3000 R.P.M. - 25.0 Volts A.C.3300 R.P.M. - 26.5 Volts A.C.3600 R.P.M. - 29.0 Volts A.C.

If low or no voltage is experienced, replace thealternator. If the alternator puts out the minimumA.C. voltage, replace the diode.

Yellow

Red

A.C.

DIODE

A.C.

83

3 Amp A.C. Lighting Alternator Models: H & HSK 30- 35, HS & HSSK 40, H & HSK 50-60,HH50-60, HM & HMSK 70-80-100, HHM80

84

Yellow

Green

YellowHEAD & TAIL LIGHT

IGNITION GROUND

STOP LIGHT

Before making any exterior tests, check for aninoperative switch, shorted wires and burned outheadlight and/or stop tail light. To check out thealternator, check the A.C. lead to ground (diag. 84).

With engine running the minimum values shouldread:2500 R.P.M. - 8.0 Volts A.C.3000 R.P.M. - 9.5 Volts A.C.3300 R.P.M. - 10.5 Volts A.C.3600 R.P.M. - 11.5 Volts A.C.

If the above minimum readings are noted, thealternator is okay. Check for defective lights, wiringor switches. If less than the above readings, thealternator is defective.NOTE: ON OLDER POINT IGNITION SYSTEMS,THE A.C. OUTPUT LEADS ARE BLACK AND RED.

45

5 Amp Alternator System Regulator-Rectifier Under Blower Housing

CHECKING THE SYSTEM: An open circuit D.C.voltage check cannot be made with this system. If aknown good battery fails to maintain a charge,proceed in making an A.C. voltage test.

To do this, the blower housing must be removed,and the regulator-rectifier must be brought outsideof the blower housing.

Disconnect the red D.C. output connector at thewiring harness (not at the regulator/rectifier) andconnect the probes from an A.C. voltmeter to thewire terminals at the regulator-rectifier (diag. 85).

CAUTION: AT NO TIME SHOULD THEENGINE BE STARTED WITH THEBLOWER HOUSING REMOVED.

With the engine running the minimum values shouldread:2500 R.P.M. - 19.0 Volts A.C.3000 R.P.M. - 23.0 Volts A.C.3300 R.P.M. - 26.0 Volts A.C.3600 R.P.M. - 28.0 Volts A.C.

If the minimum values are noted; the regulator-rectifier is defective. If less than above readings, thealternator is defective.

85

CHECKING THE SYSTEM: To check the system,disconnect the D.C. or B (+) wire at the switch endand measure D.C. voltage between the lead andground (diag. 86).

With the engine running the minimum values shouldread:2500 R.P.M. - 9.0 Volts D.C.3000 R.P.M. - 11.0 Volts D.C.3600 R.P.M. - 14.0 Volts D.C.If the minimum readings are noted, system is okay.

7 Amp Alternator System Regulator-Rectifier External to Engine

86

REGULATOR/RECTIFIERMUST BE GROUNDED

D.C. VOLTMETER

B + TERMINAL WIRE


CAUTION: BLOWER HOUSING MUST BEINSTALLED WHEN RUNNING ENGINE

A.C. VOLTMETER

YELLOW

REDNOTE: D.C. OUTPUT MUST BE DISCONNECTED TO PERFORMA.C. OUTPUT TEST.

46

Check for a defective ammeter, wiring, etc. If lessthan the above readings, disconnect the plug fromthe regulator-rectifier, and insert the A.C. voltmeterprobes in the two outside terminals (diag. 87).

With the engine running the minimum values shouldread:2500 R.P.M. - 12.0 Volts A.C.3000 R.P.M. - 14.0 Volts A.C.3600 R.P.M. - 18.0 Volts A.C.

If the minimum readings are noted, the regulator-rectifier is defective. If less than the above readings,the alternator is defective.

A.C.

87

In this system, the regulator and rectifier arecombined in one solid state unit mounted under theblower housing of the engine.

Various types of regulator-rectifiers have been usedon different applications. Test procedures for alltypes are the same. However, regulator styles arenot interchangeable (diag. 88).

CHECKING THE SYSTEM: An open circuit D.C.voltage check cannot be made with this system. If aknown good battery fails to maintain a charge,proceed in making an A.C. voltage test.

To do this, the blower housing must be removed,and the regulator-rectifier must be brought outsideof the blower housing.

Keep the A.C. leads attached to the regulator-rectifier. Install the blower housing with the regulator-rectifier outside the housing. With an A.C. voltmeterprobe the regulator as shown (diag. 89).

CAUTION: AT NO TIME SHOULD THE ENGINEBE STARTED WITH THE BLOWER HOUSINGREMOVED.

With engine running, minimum A.C. voltage fromlead to lead should be:2500 R.P.M. - 16.0 Volts A.C.3000 R.P.M. - 19.0 Volts A.C.3300 R.P.M. - 21.0 Volts A.C.3600 R.P.M. - 23.0 Volts A.C.If the minimum readings are noted, the alternator isokay. If the system fails to charge a known goodbattery, the regulator-rectifier must be defective.

88

89

D.C. OUTPUT LEAD-RED

MAGNETO GROUND - GREEN

A.C. VOLTMETER

YELLOW

RED

INSERT PROBES INTOCONNECTOR SLOTS. DONOT REMOVECONNECTOR WIRES

CAUTION: BLOWERHOUSING MUST BEINSTALLED WHENRUNNING ENGINE

7 Amp Alternator System Regulator-Rectifier Under Engine Block Housing, Models:H50-60, HH50-60, HM70-80-100, HHM80, TVM125-140-170-195-220

47

10 Amp A.C. Alternator

CHECKING THE SYSTEM: Unplug the connectorat the wiring harness supplied by the OEM. Proceedto make an A.C. output check. Place one lead of theA.C. voltmeter into the center of the connector.Place the other lead to engine ground (diag. 90).With the engine running the minimum values shouldread:2500 R.P.M. - 16.0 Volts A.C.3000 R.P.M. - 20.0 Volts A.C.3300 R.P.M. - 22.0 Volts A.C.If less than above output, the alternator assembly isdefective. 90

A.C. OUTPUTYELLOW A.C.

10 Amp Alternator System - Regulator - Rectifier-External to Engine

In this system, the regulator and rectifier arecombined in one solid state unit.

CHECKING THE SYSTEM: To check the system,disconnect the D.C. or B (+) wire at the switch endand measure D.C. voltage between the lead andground (diag. 91).

With the engine running the minimum values shouldread:2500 R.P.M. - 13.0 Volts D.C.3000 R.P.M. - 16.0 Volts D.C.3600 R.P.M. - 20.0 Volts D.C.

If the minimum values are noted, the system is okay.Check for a defective ammeter, wiring, etc. If lessthan the above readings, disconnect the plug fromthe regulator-rectifier, and insert the A.C. voltmeterprobes in the two outside terminals (diag. 92).


If the minimum readings are noted, the alternator isokay.

92

REGULATOR/RECTIFIERMUST BE GROUNDED

D.C. VOLTMETER

A.C.

B + TERMINAL WIRE

91

48

16 Amp Alternator System with External Regulator

D.C. OUTPUT - RED

SOLENOID

GREEN

LIGHT

SWITCH

AMMETER

MAGNETOGROUND

BATTERY

REGULATEDD.C. OUTPUT

FUSE

YELLOW

REDNOTE: D.C. OUTPUT MUST BE DISCONNECTED TO PERFORMA.C. OUTPUT TEST.

CHECKING THE SYSTEM: An open circuit D.C.voltage check cannot be made with this system. Ifa known good battery fails to maintain a charge,proceed in making an A.C. voltage test.

Disconnect the red D.C. output connector at thewire harness and connect the probes from an A.C.voltmeter to the wire terminals at the regulator-rectifier (diag. 93).

With the engine running the minimum values shouldread:2500 R.P.M. - 21 Volts A.C.3000 R.P.M. - 26.5 Volts A.C.3600 R.P.M. - 31.0 Volts A.C.

If the minimum values are noted, the alternator isoperating properly. If less than the above values arenoted, the alternator is defective.

93

20 Amp Alternator System

In this system, the regulator and rectifier arecombined in one solid state unit which is mountedinto the blower housing of the engine.

CHECKING THE SYSTEM: An open circuit D.C.voltage check cannot be made. If a known goodbattery fails to maintain a charge, proceed to makean A.C. voltage test.

Disconnect the plug leading to the regulator rectifier,and insert the A.C. voltmeter probes into the twooutside terminals.


If the minimum readings are noted, alternator isokay. If the system fails to charge a known goodbattery, regulator-rectifier must be defective.

94

YELLOW(A.C. LEAD)

GREEN(MAGNETO SHUT-OFF)

YELLOW(A.C. LEAD)

A.C.YELLOW

YELLOW

GREENRED

GREEN(MAGNETO SHUT-OFF)

RED(D.C. WIRE)

RECT./REG.

49

D.C. Output

(2) Headlights

Switch

A.C. Output LeadYellow D.C. Output

Lead Red

A.C. OutputView A-A

Key Switch

Ammeter

Battery

Magneto Ground

Starting Motor

Solenoid

Yellow

Red

Diode

A

A

BM

S

Typical Wiring Circuits3 Amp D.C. / 5 Amp A.C. Alternator

3 Amp Alternator (D.C.)

Diode View A-A

Magneto Ground Lead (Green)D.C. Output Lead (Red)

A

AHEAVY DUTY KEY SWITCHOFF-MAGNETO TO GROUNDRUN-MAGNETO OPEN START-BATTERY TO STARTER

Green Insulation

Red Insulation

BATTERY

(+)

(-)

B.

M.

S.

6 Amp Fuse on SomeEarly Models

50

Typical Wiring Circuits - continued

7 AMP ALTERNATOR SYSTEMSEXTERNAL REGULATOR-RECTIFIER

5 Amp Alternator System

A

A

Switch

Light, etc.

D.C (+)

Fuse

MS

B

R

A Key SwitchAmmeter

Battery

Magneto Ground

D.C. Output Red

Solenoid

Magneto Ground Green

A.C. Yellow

View A-A

A

AA.C. Output

Light, etc.

Switch

A.C. Yellow

B B

Battery - RedView B-B

A.C. A.C.B+

Regulator/RectifierD.C. (+)

B A

MS

RAmmeter

Battery

(-)

(+)

Solenoid

Yellow

YellowGreen

Provided by Tecumseh, Regulator/Rectifier Mounted and Located UnderBlower Housing

Green

Red

A

A

D.C. (+)

Light, etc.

Switch

MagnetoGround

Key Switch

A

SMR

B

(+)

Ammeter

Battery

-

+

Solenoid

7 AMP & 12 AMP D.C.REGULATED ALTERNATOR

51


D.C. Output -Red

Green

Fuse

RegulatedD.C. Output

MagnetoGround

Battery

Ammeter

B

RS

M

A

(+)

Switch

Light

(+)

Solenoid

16 AMP ALTERNATOR SYSTEMS

A.C. Output YellowRemote StopTerminal

Diode

LightSwitch (2) Headlights

Double PoleDouble ThrowSwitch(+)

ElectricClutch

Resistor 1Ohm 20Watt

Ammeter

Starter KeySwitch

B

SM

12 V.

Battery

(-)

(+)

(+)

(+)

Solenoid

MagnetoGround

StartingMotor

Yellow

Green

A

A

MagnetoGround(Green)

A.C.(YellowLeads)

A.C. Output

Light, etc.

Switch

A.C. A.C.B+

Regulator/Rectifier

Key Switch

A

R SM

B

(+)

Ammeter

Battery

-

+

Solenoid


52



Yellow

Green

Magneto Ground (Green)

A.C. Output (Yellow)A

A

MagnetoGround

Light, etc.

Solenoid

(+)

Switch

Battery

+

-

Ammeter

D.C. (+)Fuse

Regulator/Rectifier

B+

A.C. A.C.

R

SM

A

B

View A-A

-

Provided by Tecumseh,Regulator/Rectifier Mountedand Located Under BlowerHousing

Green

Red

MagnetoGround Lead(Green)

D.C. OutputLead (Red)

A

A

Solenoid

MagnetoGround

Light, etc.

D.C. (+)(+)

+

Battery (+)

(+)

B

S

AMR

Fuse

Switch

Ammeter

53

Identification Number LocationsEarly Models were not identified with a model number on the unit.

THE MODEL NUMBER WILL BE FOUND ON: A. Metal tag or decal attached to unit as illustrated.B. Stamped on unit as illustrated.

Peerless Identification

SAMPLE (OLD STYLE)MOD 506

PEERLESS1 275 1374

Individual Serial NumberManufactured on the 275th DayManufactured in 1991

SAMPLE (NEW STYLE)MST205- oool l l l l l l l l lSERIAL 6 0 0 2

Serial Number Julian Date (The Second Day of1996)

Specification NumberManufacturersRequested Features

RIGHT ANGLE DRIVES100 SERIES

A or B

A or B A or B

1200 SERIES

1100 SERIES

600 SERIES

A or B

700 SERIES A

2600 SERIES

A

2800 SERIES

A

A

810 SERIES801 SERIES

900 SERIES920 SERIES930 SERIES

A

A

910 SERIES

A

1300 SERIES

A

820 SERIES

A915 SERIES

A 2400 SERIES

A or B2300 SERIES

A or BMST and VST

2500 SERIES

A

54

205 - 027C8194A0048

The recent warranty audit referenced in bulletin number 123 suggested we review the way our newTecumseh/Peerless models are identified. The review found improvements were needed in the identificationsystem to make them standard with the new emission regulations requirements covering engine productand the New ESA 157 Claim Form.

As a result, we have changed the product ID tag to make it easier to read. Should this data be needed forservice or warranty situations these improvements will make locating the needed model and specificationinformation easier.

Example Numbers 1 and 2 below, show the present bar code labels currently being used. We have identifiedthe important fields of information that is required for warranty claims.

In addition, a new easier to read bar code label (No. 3 below) is being introduced on all units provided afterOctober 1, 1998. Again we have highlighted the information you are required to supply.

This information is critical for prompt warranty reimbursement to your shop, please pay close attention tothis number.

SPECIFICATION NUMBERREQUIRED FOR WARRANTY



MODEL NUMBER REQUIREDFOR WARRANTY

MODEL NUMBER REQUIREDFOR WARRANTY

MODEL NUMBER REQUIRED FORWARRANTY

D.O.M. (DATE OF MANUFACTURE)ORIGINALLY SERIAL NUMBER



"NEW TYPE"

1 2

3

PEERLESS

PEE

RLE

SSTECUMSEH

TEC

UM

SEH205 - 027C

MODEL DATE SERIALMST - 206 - 502ADATE MFG. SERIAL NO.

6304A00013

PEE

RLE

SS

TEC

UM

SEH

7070A - 0005

MODEL SPEC

D.O.M.

VST - 205 - 020C

Peerless Identification - continued

55

Transaxle Troubleshooting

95

96

97

98

In-Line Shift Models (i.e. 800, 820, 915, 920, 930 MST)

Transaxle troubleshooting can be a mystery to many technicians, but by using a common sense approachthat most technicians use for engine troubleshooting, the mystery will disappear and be replaced withconfidence, skill and eventually, mastery of transaxle service.

Before you begin to take off the wheels (the hardest part of transaxle repair) check the associatedequipment.

A. Check belts for proper adjustment.B. Check for proper adjustment of brake, clutch, shifter and related linkages, etc.C. Check pulleys for sheared keys and proper belt disengagement.D. Check for proper shifting by removing drive belt. If transaxle does not shift freely it would indicate

an internal transaxle problem.

After you have made all preliminary checks it may now become necessary to remove the transaxle fromthe equipment.

The first area to check after removing the transaxlecover is the shifting keys. The keys are the safetylink to protect against serious gear damage. Checkkeys for breaks, cracks, stress marks, worn shiftkey ends and proper spring tension (diag. 95).

Check input bevel gears for excessive wear. If gearsare damaged, the cover should be checked fordistortion (diag. 96).

To properly troubleshoot and inspect the transaxlefurther, it is necessary to clean grease from partsduring disassembly.

During disassembly check shifting gears andwashers for proper assembly.

Check countershaft splines and splines on innerdiameter of countershaft gears (diag. 97).

Check reverse sprockets for damaged teeth and ifapplicable, inner diameter spline area. Check chainfor damage or excessive stretching.

Check differential ring gear and bevel gears forexcessive wear. Bevel gears should be replaced asa set if any gear is damaged. When replacing snaprings, put flat side of snap ring against the thrust sideof gear. Do not over stretch the snap rings whenremoving and installing (diag. 98).

Check axles and as applicable, axle bearings ortransaxle case/cover for wear or damage.

56

Hard Shifting Transaxles and Drive BeltsOften hard shifting is blamed on an internal problem in the transaxle.To determine if the problem is transaxle or equipment related make these simple checks.1. Turn the unit off so that all power is removed to the transaxle2. With the unit off move the shift lever through the shift gate. Movement of the lever should have only

slight resistance. The shifting effort should be equal when the engine is off and when running. Ifthe unit is difficult to shift the problem would be internal and the transaxle would need to be removedand repaired

3. If the unit shifts with ease, check the following areas that would be equipment related. Check tosee if the belt is releasing from the pulley on the engine and transmission / transaxle, it may requirethat the belt guides be repositioned. The distance required from the pulley to the guide is typically1/16" to 3/16" (1.6 mm - 4.8 mm), always check the O.E.M. specs.

4. Check to see if the pulley is damaged and may not be releasing the belt.5. Make sure that the belt is the correct belt in case the customer has replaced it with a non original,

possibly more aggressive belt.6. Check the brake/clutch pedal to make sure that when the pedal is depressed that the idler pulley

is releasing the belt tension before it applies the brake. If this does not happen the unit will still beunder a load and be impossible to shift

7. The final area to check would be for damaged or binding shift linkage.

Hard shifting with the engine off could be caused by:1. Shift linkage out of adjustment.

2. Corrosion in the transaxle or transmission.

3. Damaged shift keys, gears, or shifter brake shaft.

4. Belt guides missing or improperly adjusted (see equipment manufacturer specs.)

For proper declutching to occur, it is very importantthat the engine belt guide be set at apredetermined gap (set by the manufacturer)and away from the belt with the belt engaged.

With clutch disengaged, it is very important thatthe belt blossoms away from the engine pulley.Belt must stop turning before transaxle shiftingcan occur.

1/16" to 3/16" (1.6 mm - 4.8 mm)

THIS DIMENSIONVARIES FROM EACHMANUFACTURER

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VST TroubleshootingThe information on this page has been provided to help understand the internal operation of the VST. Donot use this information to attempt any internal repairs. Tecumseh's current policy on hydrostatic transaxlesthat have internal failures is to replace the complete unit. This has not changed. However, Tecumseh wouldlike to provide a failure checklist to assist in making an accurate evaluation of the complete tractor toeliminate any unnecessary replacements. Here is a list of items to check and corrective actions to take.To properly test the unit for power loss.

1. Allow the unit to cool before trying the following steps.2. Put the shift lever in a position that is 1/2 of the travel distance from neutral to forward.3. Place the tractor on a 17 degree grade.4. Drive the tractor up the grade (without the mower deck engaged). The loss of power experienced

should be approximately 20%. This is considered normal. If the loss of power is approximately 50%,this would be considered excessive.

5. Bring the unit to neutral, shift into forward and note the response. Care should be taken to move thelever slowly to avoid an abrupt wheel lift.

To determine if the problem is with the hydro unit, all external problem possibilities must be eliminated. Hereare some potential problem areas

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