Tecumseh HXL, AV600, TCH200, AV520, HSK User Manual

...

Tecumseh Quick Reference

Service Information

Covers Engine and Transmission Product

Form No.695933 R 7/00

Introduction

This booklet contains the quick reference and basic troubleshooting information previously found on Tecumseh wall charts and in the Technician's Handbooks.

This booklet is designed to be used as a work bench quick reference guide when servicing Tecumseh engines and motion drive systems.

Technician's Note:

Tecumseh engines are manufactured to meet EPA and CARB standards. As a technician, it is unlawful to re-calibrate or replace a fuel nozzle or jet (bowl nut) with a part from any other carburetor that was not originally designed for that engine. All speed adjustments must remain within the limits that are specified for each engine and are not to exceed the maximum. This can only be deviated from if specifically approved by Tecumseh Products, EPA and CARB.

Note: Torque specifications listed should not be confused with the torque value observed on

engines which have been run. The Torque specifications take relaxation into account so sufficient clamping force exists

after an engine has reached operating temperature. Torques listed are intended to cover highly critical areas. More extensive torques are found

in the respective repair manual.

Torque Specifications

TWO-CYCLE ENGINE SERIES

840 - 850 TWO-CYCLE ENGINE SERIES

Location Inch lbs. Torque Nm Engine Designation

TVS

TVXL

HSK

HXL

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

Location Inch lbs. Torque Nm Engine Designation

TC200

TC300

TCH200/

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)

Location Inch lbs. Torque Nm Engine Designation

AV520/600

TVS600

AH/HSK600

300

AH520

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 • • • •

Two Cycle Troubleshooting

As an aid in troubleshooting any piece of equipment, interview the customer, and review conditions and symptoms of the problem. Examine exterior for clues: leaks, excessive dirt, damaged or new parts.

FUEL SYSTEM

Engine Will

Not Start

Check if spark

plug is wet or dry

Wet

Dry

Defective

spark plug

Restricted

air filter

Improper fuel mix

or stale fuel

Exhaust ports

plugged

Carburetion

problems due to

flooding, over

priming, etc.*

Review with customer

priming or choking

procedure

(3-5 primes, if

equipped, waiting 2

seconds between

each prime)

Carburetion problem*

(bad bowl gasket)

Check fuel supply

and fuel cap vent

Restriction in

fuel system (filter,

screen)

Ignition System

Crankcase seals

or gaskets leaking

NOTE: Refer to Technician's Handbook for a more

detailed list of remedies.

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

(CONTINUED ON NEXT PAGE)

Poor

compression

Damaged reed, port

plugs, seals or

gaskets

Two Cycle Troubleshooting - continued

IGNITION SYSTEM

Engine Will

Not Start

Check for spark

Spark

Check flywheel for

correct key, damaged

key or key adaptor

Set proper air gap on

external coil

Set proper point gap,

check condensor and

timing (if equipped)

Test coil for

intermittent or weak

spark

Check electric starter

if applicable

No Spark

Replace spark plug

Isolate engine from all equipment (disconnect wiring harness), repeat

Spark

Equipment problem,

check switches, wiring

and equipment

controls

Parasitic load too high

test

No Spark

Engine problem,

check for shorts or

grounds in wiring

Test ignition module

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

Note: Torque specifications listed should not be confused with the torque value observed on

engines which have been run. The Torque specifications take relaxation into account so sufficient clamping force exists

after an engine has reached operating temperature. Torques listed are intended to cover highly critical areas. More extensive torques are found

in the respective repair manual.

Torque Specifications

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

Location Inch lbs. Torque Nm Engine Designation

TVS

TNT

ECV

LAV

H/HSK

HS/HSSK

OVRM

VLV

LEV

OHH

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 • • • • • • • • • •

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

Location Inch lbs. Nm Engine Designation

Torque

TVM & TVXL

170-195-220

HM/HMSK70-100

OVM/OVXL,

TVM125, 140

H50-60

V70

H70

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 • • • • • •

OHV120-125

OHSK80-130

OHM120

OHV135-145

203 Series

OHV15-17.5

OHV11-13,OHV110-

135, 206 Series

204 Series

Torque Specifications - continued

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

Location Inch lbs. Nm Engine Designation

Torque

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)

Location Inch lbs. Nm Engine Designation

Torque

TVT

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 •

Four Cycle Troubleshooting

As an aid in troubleshooting any piece of equipment, interview the customer, and review conditions and symptoms of problem. Examine exterior for clues: leaks, excessive dirt, damaged or new parts.

FUEL SYSTEM

Engine Will

Not Start

Check if spark plug is

wet or dry

Wet

Defective

spark plug

Restricted air filter

Improper or

stale fuel

Carburetion problems

due to flooding, over

priming, etc.*

Ignition system

Dry

Review with the

customer proper

priming procedure

(3-5 primes, waiting

2 seconds between

each prime)

If equipped with a

choke, check for full

travel. Check throttle

cable and control for

proper adjustment.

Check fuel supply and

fuel cap vent

Restriction in fuel

system (filter)

Carburetion problem*

(bad bowl gasket)

Poor

compression

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

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

Four Cycle Troubleshooting - continued

IGNITION SYSTEM

Engine Will

Not Start

Check for

spark

Spark

No Spark

Check flywheel for

correct key, damaged

or sheared key

Set proper air gap on

external coil

Set proper point gap, check condensor and

timing

Test coil for

intermittent or weak

spark

Isolate engine from all equipment (disconnect wiring harness), repeat

Spark

Equipment problem,

check switches,

wiring and

equipment controls

Parasitic load too

high

Replace spark plug

test

No Spark

Engine problem,

check for shorts or

grounds in wiring

Test ignition

module

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

Tecumseh 2 Cycle Diaphragm Adjustments

NOTE: For meeting emission requirements, some

carburetors have fixed-main or idle jets. The absence of the adjustment screw indicates fixed jets and no adjustment is necessary.

Diaphragm-Dual Adjustment.

Turn mixture adjusting screws in finger tight to the closed position, then one (1) turn out from closed position. This setting is approximate. This 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

the engine is cold.

IDLE MIXTURE SCREW

MAIN MIXTURE SCREW

NOTE: If no tension spring is present, it may be a fixed jet.

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

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

With the engine idling and throttle lever against the idle speed regulating screw, turn the low speed adjustment screw slowly clockwise from the NORMAL setting until the engine falters. Remember this location. Turn the screw counterclockwise until engine just starts to sputter or drops in R.P.M.. Remember this location. Turn the screw clockwise until it is halfway between your first position where the engine faltered and your last position where the engine started to sputter. This will be the optimum low speed setting on your carburetor.

Next run the engine at governed speed. The high speed adjustments are made basically the same as the low speed adjustments, with the exception of the settings being made 1/8 of a turn at a time, from the NORMAL settings. NOTE: It may be necessary to re-check the idle mixture adjustment after performing the high speed adjustment.

Diaphragm-Single Adjustment.

Turn the mixture adjustment screw finger tight to the closed position, then one (1) turn out from the closed position. This setting is approximate and will allow the engine to be started so the carburetor can be finetuned.

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

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

NOTE: If the engine falters or stops after the choke lever is moved to the "OFF" position, open the mixture

adjusting 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. Turn the mixture screw slowly clockwise from the NORMAL setting until the engine falters. Remember this location. Turn the screw counterclockwise until the engine just starts to sputter or drops in R.P.M. Remember this location. Turn the screw clockwise until it is halfway between your first position where the engine faltered and your last position where the engine started to sputter. This will be the optimum setting on your carburetor.

TC Series Governor Adjustment

Three different styles of governor systems are used on TC engines. Use the following illustrations (diags. 2 and 3) to identify the governor system used and the following procedure to adjust the governed engine speed.

1. Allow the engine to run for at least 5 minutes to reach operating temperature. Make sure the air filter (if equipped) is clean and the choke is in the off position.

2. Using a Vibratach (part# 670156) or other tachometer, determine the engine's R.P.M. at idle and wide open throttle. Refer to Microfiche card 30, or a computer parts look-up program to obtain the recommended engine speeds.

3. Using the applicable illustration, either bend the speed adjusting lever toward the spark plug end of the engine to decrease high speed R.P.M., or bend the lever in the opposite direction to increase R.P.M. On TC Type II engines, turn the speed adjusting screw out to increase or in to decrease engine high speed R.P.M. If the speed adjustment screw is turned out to increase the engine R.P.M., the speed control lever must be moved to allow the speed control plunger to contact the speed adjustment screw.

4. The low speed is set by moving the throttle control to the lowest speed position and adjusting the low speed adjustment screw on the carburetor.

HOOK SPRING ON NOTCH

TYPE I (style 2)

HOOK SPRING ON NOTCH

TYPE I (style 1)

SPEED ADJUSTING LEVER

BEND TO INCREASE SPEED BEND TO DECREASE SPEED

SPEED ADJUSTING LEVER

1. AIR VANE

2. BACKLASH SPRING

3. GOVERNOR LINK

4. GOVERNOR SPRING

5. MOUNTING SCREW

6. SPEED ADJUSTMENT SCREW

7. SPEED CONTROL BODY

8. SPEED CONTROL LEVER

9. SPEED CONTROL PLUNGER

SPRING

POSITION 1 TYPE II: (style 3)

HIGH SPEED GOVERNOR ADJUSTMENT

HOOK SPRING ON NOTCH

POSITION 2

OUT TO INCREASE IN TO DECREASE

Spring Color Spring Position Orange or Green 1 Pink, Red, or Black 2

SPRING

INSERT THROTTLE LINK AND SPRING HERE

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

Carburetor Pre-Set and Adjustment

Both the Walbro and the Tillotson carburetors used on TC engines have non-adjustable main mixture jets. Only the idle mixture is adjustable by turning the idle mixture screw. Use the following procedure to pre-set the idle mixture screw. Turn the idle mixture screw (clockwise) finger tight to the closed position, then turn the screw counterclockwise to obtain the proper preset (diag. 4).

Walbro Model WTA, WT 1 - 1-1/8 turns Tillotson Model HU 1-1/4 - 1-3/8 turns

Final Idle Mixture Adjustment

Start the engine and allow it to reach normal operating temperature (after 3-5 minutes). As the speed control is set at the idle position, turn the idle mixture screw slowly clockwise until the engine R.P.M. just starts to decrease. Stop and note this screw position. Turn the idle mixture screw slowly counterclockwise, the engine will increase in R.P.M. Continue to slowly turn the screw until the engine R.P.M. starts to decrease. Note this position and turn the mixture screw back clockwise halfway between the two engine R.P.M. drop off positions. The idle mixture adjustment is complete.

Some carburetors came equipped with a main mixture adjusting screw. To adjust the main mixture, follow the steps for idle adjustment.

IDLE SPEED ADJUSTMENT SCREW

IDLE MIXTURE SCREW

Emissionized Tillotson

Similar in design and operation, the Tillotson emission carburetor uses a fixed main jet with an adjustable idle. The idle circuit has a limiter cap to prevent over richening. The cap is locked onto the adjustment screw in a rich position, allowing only a leaner adjustment. The main is fixed on these, which means that the main mixture limiter is non-functional on Tecumseh built engines (diag. 4a).

In compliance with E.P.A. and C.A.R.B. regulations the following procedure must be followed.

NOTE: These caps can be removed for servicing of 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 reinstalled to this same static setting. Replacement of the caps is required to maintain E.P.A. and C.A.R.B. emission compliance.

IDLE MIXTURE

LIMIT SCREW

FIXED MAIN (MIXTURE SCREW

NOT FUNCTIONAL ON MOST TECUMSEH BUILT ENGINES)

IDLE SPEED ADJUSTMENT SCREW

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

IDLE SPEED

ADJUSTMENT

HIGH SPEED ADJUSTMENT

Linkage Location

To aid in the proper reassembly of the governor linkage, mark the linkage locations.

HOLDING

SCREW

Static Governor Adjustment

To adjust the static governor, loosen the holding screw, rotate the governor arm and slotted shaft in

STATIC GOVERNOR ADJUSTMENT SCREW

the direction that will open the throttle to the wide open position, and then re-tighten the holding screw.

HSK/HXL840-850

IDLE RPM

ADJUSTMENT

SCREW

HIGH SPEED RPM ADJUSTMENT SCREW

The HXL840 - 850 Series with variable speed control have the following adjustments. Idle speed is set at the carburetor crack screw. High speed is set with the screw shown above. Always check Microfiche

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

card 30 or Parts Smart computer program for correct speed settings.

Governor and Linkage for Air Vane

BEND TAB TO ADJUST RPM

VANE ASSEMBLY

INCREASE

DECREASE

INCREASE

DECREASE

BEND TAB

TO ADJUST HIGHSPEED ROTATE CLOCKWISE TO INCREASE COUNTERCLOCKWISE TO DECREASE

HORIZONTAL FIXED SPEED

PLASTIC AIR VANE GOVERNOR

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 removed from the carburetor.

Governors and Linkage for Air Vane - continued

ADJUST RPM BY LOOSENING SCREW AND SLIDING BRACKET

INCREASE

DECREASE

IDLE RPM ADJUSTMENT

IDLE MIXTURE

HIGH SPEED RPM ADJUSTMENT

THIS HOLE NOT PRESENT ON ALL MODELS

SPRING

HORIZONTAL FIXED SPEED

(ALUMINUM AIR VANE GOVERNOR)

ADJUST RPM BY LOOSENING SCREW AND SLIDING BRACKET

INCREASE

DECREASE

HORIZONTAL FIXED SPEED

SPRING

GOVERNOR LINK

VARIABLE SPEED-REMOTE CONTROL

IDLE RPM ADJUSTMENT

IDLE MIXTURE

VERTICAL ENGINE

HIGH SPEED RPM ADJUSTMENT

THIS HOLE NOT PRESENT ON ALL MODELS

VERTICAL ENGINE

FIXED SPEED-REMOTE CONTROL

SPRING

IDLE RPM ADJUSTMENTS

VARIABLE SPEED

MANUAL CONTROL

HIGH SPEED RPM ADJUSTMENT

THIS HOLE NOT PRESENT ON ALL MODELS

SPRINGVERTICAL ENGINE

RPM ADJUSTMENT

VERTICAL ENGINE FIXED SPEED

THIS HOLE NOT PRESENT ON ALL MODELS

SPRING

Static Governor Adjustments

The purpose of making a static governor adjustment is to remove all free-play between the governor spool and the carburetor (see illustration). Any freeplay here will result in hunting/surging or erratic running. After completing this procedure, always re-check the engine speeds using the steps outlined in the following pages.

SPRING

CHOKE

THROTTLE

GOVERNOR

ROD

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 the shaft or shaft/clip assembly in the same direction and tighten the screw.

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

Governor Shaft Pressed In Depth

NO FREE

PLAY

GOVERNOR

SPOOL

WIDE OPEN THROTTLE

CLOSED THROTTLE

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

Engine Model Exposed Shaft Length

ECH 90 Mounting flange to top ECV 100 1.319 - 1.334" H 30, 35 (33.502 - 33.883 mm) HS 40, 50 LAV (all) LEV (all) OHH (all) OVRM (all) TNT 100, 120 TVS (all) VLV (all)

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

HH 100, 120 Mounting flange to top VH 100 1.016 - 1.036"

(25.806 - 26.314 mm)

Engine Model Exposed Shaft Length

H 50, 60, 70 Mounting flange to shoulder HH 60, 70 1.283 - 1.293" HHM 80 (32.588 - 32.842 mm) HM 70, 80, 100

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

OHM 90-120 Mounting flange to top OHSK 90-130 1.085 - 1.100"

(27.559 - 27.940mm)

OH 120-180 Mounting flange to top

1.00" (25.400mm)

TVT - V -Twin Mounting flange to top

1.196 (3.969 mm)

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

RETAINING

RING

Retainerless Governor System for Small Frames*

SPOOL

RETAINING

RING

GEAR ASSY.

(GOV.)

WASHER

SHAFT

* As of August 1992, all small frame engines, including VLV40-6.75, use

a retainerless shaft. Service replacement shafts will be retainerless for all small frame and VLV engines.

SPOOL

UPSET ROLLED

SHAFT

GEAR ASSY.

(GOV.)

WASHER

NOTE: Gear assembly must have .010 - .020 (.25 - .50 mm) end

play after shaft is installed into flange.

* As of August 1992, all small frame engines, including VLV40-

6.75, use a retainerless shaft. Service replacement shafts will be retainerless for all small frame and VLV engines.

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

TYPE I

RETAINING RING

GEAR ASSY. (GOV.)

SPOOL

WASHER

IDLER GEAR

TYPE II

SPOOL

UPSET RETAINER

SHAFT

GEAR ASSY. (GOV.)

WASHER

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

Medium Frame Vertical

Models: TVM125, 140, 170, 195, 220 - V50,60,70 VH50,60,70

RETAINING

RING

SPOOL

WASHER

RETAINING

RING

GEAR ASSY.

(GOV.)

WASHER

SPACER

SHAFT

NOTE: Gear assembly must have .010 - .020 (.25 - .50 mm)

end play after shaft is installed into flange.

* As of August 1992, all small frame engines, including VLV40-6.75, use

a retainerless shaft. Service replacement shafts will be retainerless for all small frame and VLV engines.

Medium Frame Horizontal

Models: HH60,70 - H50,60,70 - HM70,80,100 HMSK

SHAFT

ROD ASSY.

(GOV.)

SPOOL

OHM120 - OHSK 80-130

SPOOL

WASHER

RETAINING RING

GEAR ASSY. (GOV.)

WASHER

RETAINING

RING

GEAR

ASSY.

(GOV)

BRACKET

SCREWS

OVM120, OVXL120, 125 - OHV11-17

SPOOL

WASHER

RETAINING RING

WASHER

SPACER

SHAFT

OH120, 140, 160, 180

SPOOL

GEAR ASSY. (GOV.)

WASHER

SPACER

SHAFT

NOTE; SPACER MAY BE PART OF THE GEAR ASSEMBLY.

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

WASHER

GEAR & SHAFT ASSY. (GOV.)

WASHER (CAPTURED UNDER GEAR)

Engine Speed and Mixture Adjustments

3-5 H.P. Vertical Shaft Engines

NOTE: Starting and operating problems may exist

when engines are used at high elevations (over 4,000 feet above sea level). In cases where a fixed main carburetor is used, refer to Bulletin 110 for correction. Engines which are identified as

compliant with CARB (California Air Resources Board) or EPA (US Environmental Protection Agency) regulations can NOT be changed from their factory jetting unless specifically authorized.

Before making any speed or carburetor adjustments be sure to adjust the governor and control bracket. See Governor Section of the Booklet.

To adjust the speed control bracket, determine whether the carburetor is an adjustable type, then proceed.

Some carburetors may have a choke lever which is operated by the speed control bracket. To adjust the speed control bracket for full choke operation, loosen the speed control bracket mounting bolts and move the speed control lever to the high speed/full choke position. Next insert a small piece of wire through the hole in the speed control bracket, choke actuating lever, and the choke lever (diag. 18). When all three holes are aligned tighten the mounting bolts.

Once the speed control bracket is adjusted, the main and idle fuel mixtures can be adjusted. Start the engine and allow it to warm up to normal operating temperature (3 - 5 minutes). Set the speed control to the HIGH or FAST position, then turn the main mixture adjustment screw in (clockwise) slowly until the engine begins to run erratic (lean). Note the position of the screw. Now, turn the screw out (counterclockwise) until the engine begins to run erratic (rich). Turn the screw in (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 same procedure used to adjust the main mixture adjustment.

NOTE: SOME CARBURETORS HAVE FIXED MAIN JETS. THE ABSENCE OF THE ADJUSTING SCREW INDICATES A FIXED JET AND NO ADJUSTMENT IS NECESSARY.

After adjusting the fuel mixtures, engine speeds can be adjusted. The correct operating speeds are found on Microfiche card 30 of the Tecumseh Master Parts Manual, or the computer parts look-up program (Part Smart). On engines with adjustable carburetors (diag. 19 and 20) the high speed adjustment will be in one of two places. The first location is on the speed control lever (diag. 19).

* ADJUSTABLE

MIXTURES, CHOKE

SPEED CONTROL MOUNTING BOLTS

HIGH SPEED ADJUSTMENT SCREW

IDLE MIXTURE SCREW

**NON-ADJUSTABLE

NO CHOKE PRIMER

SMALL WIRE (DRILL BIT)

HOLE IN BRACKET

HOLE IN SPEED CONTROL CHOKE ACTUATING LEVER

HOLE IN CHOKE LEVER

LOW SPEED ADJUSTMENT SCREW

MAIN MIXTURE SCREW

Engine Speed and Mixture Adjustments - continued

3-5 H.P. Vertical Shaft Engines

HIGH SPEED ADJUSTMENT SCREW

COUNTERCLOCKWISE TO INCREASE SPEED

CLOCKWISE TO DECREASE SPEED

MAIN MIXTURE SCREW

LOW SPEED ADJUSTMENT SCREW

IDLE MIXTURE SCREW

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

It may be necessary to preset the carburetor mixture screws.

Tecumseh Carburetors

Engine Model Main Pre-set Idle Pre-set

All models with float-type carburetors 1-1/2 turn 1 turn All models with diaphragm-type carburetors 1 turn 1 turn

SPEED CONTROL MOUNTING BOLTS

HIGH SPEED ADJUSTMENT SCREW

LOW SPEED ADJUSTMENT SCREW

SPEED ADJUSTMENT TAB

BEND TO INCREASE SPEED BEND TO DECREASE SPEED

Some speed control brackets are adjusted by loosening the speed control bracket mounting bolts and sliding the bracket all the way to the right and retightening the mounting bolts (diag. 21). The high speed adjustment screw is located on the speed control lever (diag.22) Some carburetors are fixed speed and are adjusted by bending the adjusting tab attached to the intake manifold (diag. 23).

After setting the engine speeds recheck the fuel mixtures, then recheck the engine speeds.

Engine Speed and Mixture Adjustments - continued

3-5 H.P. Vertical Shaft Engines

LOW SPEED TAB

HIGH SPEED PIN POSITION

HIGH SPEED TAB

BEND TO INCREASE SPEED BEND TO DECREASE SPEED

BEND CONTROL

BRACKET TO SET

RPM

TOOL (670326)

SNAP IN CONTROL

DECREASE

INCREASE

VERTICAL ENGINES

GOVERNED / NON-GOVERNED IDLE

With the engine running at its lowest speed, set the governed idle at the designated R.P.M. by bending the idle R.P.M. tab. Next set the non-governed idle by pushing the bottom of the governor lever away from the control brackets, so the throttle lever contacts the idle speed screw. Hold the lever in this position and turn the idle adjustment screw clockwise to increase or counterclockwise to decrease engine idle speed. The setting on the carburetor screw should be set at 600 R.P.M. below the governed idle setting. This setting prevents the throttle plate from closing when going from high speed R.P.M. to low speed R.P.M. If improperly adjusted, the engine could experience an over lean condition.

HIGH SPEED RPM ADJUSTMENT SCREW

TVS 115 ENGINE WITH DUAL

BEND TO INCREASE SPEED BEND TO DECREASE SPEED

SYSTEM CARBURETOR

HIGH SPEED RPM ADJUSTMENT SCREW

IDLE SPEED CRACK SCREW

VERTICAL SHAFT ENGINES

NOTE: ON REMOTE CONTROL THIS WILL NOT BE PRESENT

HIGH SPEED ADJUST

LOW SPEED ADJUST

TNT 100 VERTICAL ENGINES

OVRM

VLV Governor and Linkage

Governor Adjustment

With the engine stopped, loosen the screw holding the governor clamp and lever. Turn the clamp clockwise, then push the governor lever (connected to the throttle) to a full wide open throttle position. Hold the lever and clamp in this position and tighten the screw.

Linkage Installation

The solid link is always connected from the throttle lever on the carburetor to the lower hole on the governor lever. The shorter bend has to be toward the governor. The governor extension spring is connected with the spring end hooked into the upper hole of the governor lever and the extension end hooked through the speed control lever. To remove the governor spring, carefully twist the extension end counterclockwise to unhook the extension spring at the speed control lever. Do not bend or distort the governor extension spring (diag. 30).

Speed Controls

This engine has an adjustable speed control. Never exceed the manufacturer's recommended speeds.

TWIST COUNTERCLOCKWISE TO DISCONNECT

GOVERNOR SPRING

SHORT BEND

LONG BEND

HIGH SPEED ADJUSTMENT COUNTERCLOCKWISE INCREASES SPEED

NOTE:Governor adjustment screw will be a Torx

head (T-10) effective August 1, 1996 for E.C. Compliance.

Fixed Speed

High speed governor adjustment is accomplished by bending a tab to increase and decrease engine R.P.M. Effective August 1997 (diag. 31a).

LOW SPEED ADJUSTMENT COUNTERCLOCKWISE INCREASES SPEED

TOOL 670326

HIGH SPEED

ADJUSTMENT

BEND TO INCREASE SPEED BEND TO DECREASE SPEED

FIXED SPEED

31A

Engine Speed and Mixture Adjustments

5-15 HP Vertical Shaft Engines The first step is adjusting the speed control bracket

for full choke operation. Loosen the two speed control bracket mounting bolts and move the control lever to the full high speed/full choke position. Insert a piece of wire through the hole in the speed control bracket, the choke actuating lever, and the choke lever (diag. 32). When all three holes are in alignment retighten the speed control bracket mounting bolts.

SMALL PIECE OF WIRE HOLE IN CONTROL BRACKET

MOUNTING BOLTS

MOVE THE CONTROL LEVER IN THE HIGH SPEED POSITION

HOLE IN CHOKE ACTUATING LEVER

HOLE IN CHOKE LEVER

The second step is adjusting the main and idle

fuel mixtures. Start the engine and allow it to warm up 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 run erratic (lean). Note the position of the screw. Now, turn the screw out (counterclockwise) until the engine begins to run erratic (rich). Turn the screw in (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 same procedure used to adjust the main mixture adjustment screw.

NOTE: SOME CARBURETORS HAVE FIXED MAIN JETS. THE ABSENCE OF THE ADJUSTING SCREW INDICATES A FIXED JET AND NO ADJUSTMENT IS NECESSARY.

The third step is setting engine speeds. The

correct engine operating speeds are listed on card 30 of the Tecumseh Master parts manual microfiche, or the computer parts look-up program (Part Smart or Plus One). The most common speed control bracket (diag. 33) has the high speed adjustment screw located on the speed control lever. The low speed adjustment screw is the throttle crack screw on the carburetor body. Another common speed control is the governor override system (diag. 34). This system has a similar speed control bracket along with a governor adjustment lever which is attached to the engine block. Both the high speed and low speed adjustment screws are located on the governor adjusting lever.

THROTTLE CRACK SCREW

IDLE MIXTURE

SCREW

MAIN MIXTURE SCREW

LOW SPEED ADJUSTMENT SCREW

HIGH SPEED ADJUSTMENT SCREW

THROTTLE CRACK SCREW

IDLE MIXTURE SCREW

MAIN MIXTURE SCREW

GOVERNOR ADJUSTING LEVER

HIGH SPEED ADJUSTMENT SCREW

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