MTD 300 Series Shop Manual

Professional Shop Manual

300 Series Snow Thrower

MTD Products Inc - Product Training and Education Department

FORM NUMBER - 769-05547

11/2009

NOTE: These materials are for use by trained technicians who are experienced in the service and repair of outdoor power

equipment of the kind described in this publication, and are not intended for use by untrained or inexperienced individuals.

These materials are intended to provide supplemental information to assist the trained technician. Untrained or inexperi-

enced individuals should seek the assistance of an experienced and trained professional. Read, understand, and follow all

instructions and use common sense when working on power equipment. This includes the contents of the product’s Oper-

ators Manual, supplied with the equipment. No liability can be accepted for any inaccuracies or omission in this publication,

although care has been taken to make it as complete and accurate as possible at the time of publication. However, due to

the variety of outdoor power equipment and continuing product changes that occur over time, updates will be made to these

instructions from time to time. Therefore, it may be necessary to obtain the latest materials before servicing or repairing a

product. The company reserves the right to make changes at any time to this publication without prior notice and without

incurring an obligation to make such changes to previously published versions. Instructions, photographs and illustrations

used in this publication are for reference use only and may not depict actual model and component parts.

I

Chapter 1: Introduction .........................................................................................1

About the text format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Fasteners. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Assembly instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Understanding model and serial numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

The 300 series snow thrower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Chapter 2: Maintenance ........................................................................................ 5

Engine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Auger / impeller maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Auger drive system maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Traction drive system maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Chapter 3: Traction drive system .........................................................................9

Description of the traction drive system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Wheels and Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Tire Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Drive Belt Replacement: Single-speed System . . . . . . . . . . . . . . . . . . . . . . . . 10

Drive Belt Replacement: three speed drive system . . . . . . . . . . . . . . . . . . . . 11

Drive Engagement Cable Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Speed Control Cable Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Transmission Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Transmission Internals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Chapter 4: Auger System.................................................................................... 23

System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Auger belt removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Auger control cable replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Auger housing Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Auger Housing disassembly: Pulley removal . . . . . . . . . . . . . . . . . . . . . . . . . 29

Auger housing disassembly: Impeller shaft bearing replacement . . . . . . . . . . 30

Auger housing disassembly: flight removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Auger Housing disassembly: impeller brake replacement . . . . . . . . . . . . . . . 34

Auger housing disassembly: Impeller removal . . . . . . . . . . . . . . . . . . . . . . . . 36

Auger Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Chute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Table of Contents

II

INTRODUCTION

1

Professional Service Manual Intent: This manual is intended to provide service dealers with information that will

help them maintain and repair the MTD 2-Stage snow thrower.

Disclaimer: The information contained in this manual is correct at the time of writing. Both the product and the infor-

mation about the product are subject to change without notice.

About the text format

Certain flags and key words are used to indicate the nature of the text that accompanies them. They are as follows:

CAUTION: Indicates a potentially hazardous situation that, if not avoided, may result in

minor or moderate injury. It may also be used to alert against unsafe practices.

WARNING: Indicates a potentially hazardous situation that, if not avoided, could result

in death of serious injury.

DANGER: Indicates an imminently hazardous situation that, if not avoided, will result in

death or serious injury. This signal word is to be limited to the most extreme situations.

NOTE: “NOTE” is used to point-out helpful information that may not fit as a step in a procedure.

1. Numbered steps

indicate specific things that should be done, and the order in which they should be done.

1a. Sub steps

will be lettered and nested within steps. Two or more sub steps may be combined to describe

the actions required to complete a step.

• Bullet points: Indicate sub-steps or points of interest, without implying order or relative importance.

Disclaimer: This manual is intended for use by trained, professional technicians.

• Common sense in operation and safety is assumed.

• In no event shall MTD be liable for poor text interpretation, or poor execution of the procedures described in

the text.

• If the person using this manual is uncomfortable with any procedures they encounter, they should seek the

help of a qualified technician.

CHAPTER 1: INTRODUCTION

! WARNING! WARNING

! DANGER! DANGER

! CAUTION! CAUTION

INTRODUCTION

2

Safety

This Service Manual is meant to be used along with the Operator’s Manual. Read the Operator’s Manual and famil-

iarize yourself with the safety and operational instructions for the equipment being worked on. Keep a copy of the

Operator’s Manual for quick reference. Operator’s manuals may be viewed for free at the brand support website. It

will be necessary to have the complete model and serial number for the equipment.

• Be prepared in case of emergency:

Keep a fire extinguisher nearby

Keep a first aid kit nearby

Keep emergency contact numbers handy

• Replace any missing or damaged safety labels on shop equipment.

• Replace any missing or damaged safety labels on equipment being serviced.

• Grooming and attire:

Do not wear loose fitting clothing that may become entangled in equipment.

Long hair should be secured to prevent entanglement in equipment.

Jewelry is best removed.

• Protective gear: includes, but is not limited to

Clear eye protection

while working around any machinery

Protective gloves

where necessary

Armored footwear

when working around any machinery

Hearing protection

in noisy environments

Chemically resistant gloves

when working with chemicals or solvents

Respirator

when working with chemical or solvents

Appropriate tinted eye protection

when cutting or welding

Fame resistant headgear, jacket, chaps

when cutting or welding

• Remember that some hazards have a cumulative effect. A single exposure may

cause little or no harm, but continual or repeated exposure may cause very serious

harm.

• Clean spills and fix obviously dangerous conditions as soon as they are noticed.

• Lift and support heavy objects safely and securely.

• Be aware of your surroundings and potential hazards that are inherent to all power

equipment. All the labels in the world cannot protect a technician from an instant of

carelessness.

• Exhaust fumes from running engines contain carbon monoxide (CO). Carbon mon-

oxide is a colorless odorless gas that is fatal if inhaled in sufficient quantity. Only

run engines in well ventilated areas. If running engines indoors, use an exhaust

evacuation system with adequate make-up air ventilated into the shop.

! CAUTION! CAUTION

! WARNING! WARNING

! CAUTION! CAUTION

! DANGER! DANGER

INTRODUCTION

3

Fasteners

• The fasteners used on the equipment described in this manual, and the engine that powers it are a combina-

tion of metric and fractional inch. For this reason, wrench sizes are frequently identified in the text, and mea-

surements are given in U.S. and metric scales.

• If a fastener has a locking feature that has worn, replace the fastener or apply a small amount of releasable

thread locking compound such as Loctite® 242 (blue).

• Some fasteners like cotter pins are single-use items that are not to be reused. Other fasteners such as lock

washers, retaining rings, and internal cotter pins (hairpin clips) may be reused if they do not show signs of

wear or damage. This manual leaves that decision to the judgement of the technician.

Assembly instructions

• Torque specifications may be noted in the part of the text that covers assembly. They may be summarized in

tables along with special instructions regarding locking or lubrication. Whichever method is more appropriate

will be used. In many cases, both will be used so that the manual is handy as a quick-reference guide as well

as a step-by-step procedure guide that does not require the user to hunt for information.

• Lubricant quantity and specification may be noted in the part of the text that covers maintenance, and again

in the section that covers assembly. They may also be summarized in tables along with special instructions.

Whichever method is more appropriate will be used. In many cases, the information will be found in several

places in the manual so that the manual is handy as a quick-reference guide as well as a step-by-step proce-

dure guide that does not require the user to hunt for information.

• The level of assembly instructions provided will be determined by the complexity of reassembly, and by the

potential for damage or unsafe conditions to arise from mistakes made in assembly.

• Some instructions may refer to other parts of the manual for subsidiary procedures. This avoids repeating the

same procedure two or three times in the manual.

INTRODUCTION

4

Understanding model and serial numbers

The model number of a the snow thrower described in this manual is 31A-32AD762. This manual is likely to carry

useful information for a range of similar Snow Throwers that may carry a variety of MTD and private brand names.

The break down of what the model number

means is as follows:

• 31_ _ _ _ _ _ _ _ _ indicates that it is a snow thrower

• _ _A_ _ _ _ _ _ _ _ indicates that is the first generation of its basic design

• _ _ _ - _ _ _ _ _ _ _ indicates the type of starter ( - = recoil only, S = 110 V, M = 110 V+ alternator)

• _ _ _ _32_ _ _ _ _ indicates the engine used

• _ _ _ _ _A_ _ _ _ _ indicates the handle style

• _ _ _ _ _ _D_ _ _ _ indicates the housing width (D= 22” (56 cm), E= 24” (61 cm)

• _ _ _ _ _ _ _ _ 762 indicates the customer (styling, labels, color)

The serial number is 1H126G10012. The serial number

reads as follows:

• 1_ _ _ _ _ _ _ _ _ _ engineering level

• _H_ _ _ _ _ _ _ _ _ month of production (A = Jan., B = Feb., C= March, D = April, E = May...)

• _ _12_ _ _ _ _ _ _ day of the month

• _ _ _ _6_ _ _ _ _ _ _ last digit of the year

• _ _ _ _ _G_ _ _ _ _ plant it was built in (B= Willard, OH., G= Brownsville, TN., I= Canada)

• _ _ _ _ _ _1_ _ _ _ _ assembly line number

• _ _ _ _ _ _ _ _ 0012 Shift/sequence number

Additional technical and service information is be available to our company authorized service center personnel

through our corporate offices, regional parts distributors, and regional field support personnel. Please contact the

designated support office in your area or our corporate offices directly should further service information is needed.

MTD Products LLC www.mtdproducts.com

P.O. Box 368022

Cleveland, OH 44136

Telephone: (800) 800-7310

Figure 1.0

The 300 series snow thrower

The 300 series snow thrower is designed for the residential

user with moderate snow removal requirements

See Figure 1.0.

Features:

• 2-stage design

• Light-weight: 120 lbs. (54 kg.) typical

• 22” clearing swath

• Self-propelled, with internal clutch transmission

• Some versions are single-speed

• Some versions have 3 ground speeds

Maintenance

5

Proper maintenance and storage key factors in keeping outdoor power equipment dependable. Encourage your

customers to bring snow equipment in for service and storage preparation at the end of each winter. Attending to

their snow throwers maintenance in the early spring will bring-in some pre-season work and prevent the barrage of

anxious phone calls when there is 8” of snow in their driveway.

Allow the engine to cool, and drain the fuel and oil from it before starting any mainte-

nance or service procedures.

Engine maintenance

All maintenance related material for the engine is covered in our horizontal shaft engine manual # 769-04015.

Save engine storage preparation for last.

Auger / impeller maintenance

1. Inspect the augers for bending or damage.

2. Inspect each shear pin;

2a. It is possible for a pin to be sheared, with one end stuck

in place. Check both ends. Wiggle the auger to con-

firm that the shear pin is intact.

2b. Make sure that the shear pins have not ben replaced

with standard clevis pins or nuts and bolts.

2c. Use only the correct OEM shear pins.

NOTE: Shear pins help

prevent damage to the auger trans-

mission if the augers hit a solid object hidden in the snow.

NOTE: If a shear pin breaks, the unique design of the

augers on current MTD snow throwers allows the next

auger over to continue driving the one with the broken shear pin. It is possible for a customer to continue

clearing snow without noticing a damaged shear pin, but it will double the forces on the next shear pin.

NOTE: The auger gear box is sealed and filled with grease at the factory and should not require any mainte-

nance or service.

3. Wiggle the auger shaft to check the shaft-end bearings in the auger housing. Replace the bearings if they are

worn.

4. Check the auger drive transmission for any obvious damage. It is sealed a sealed unit, serviced by replace-

ment of the complete transmission and auger shaft assembly.

5. Inspect the impeller;

5a. Wiggle the impeller to confirm that the roll pins that transfer drive from the input shaft are intact.

5b. The impeller should wiggle slightly, confirming that there are no foreign objects jammed behind the impel-

ler.

NOTE: The typical customer complaint will be that the augers turn, but the snow just oozes out of the dis-

charge chute.

Figure 2.1

Shear Pins

CHAPTER 2: MAINTENANCE

! CAUTION! CAUTION

MAINTENANCE

6

6. Spray penetrating oil on the joints between;

• The auger shaft and the bearings in the auger housing that support it

• the augers and the auger shaft

• the augers and the shear pins

• the impeller shaft and the impeller

7. Check and adjust the shave plate and the skid shoes;

7a. Replace the shave plate if it is worn. It is generally best

to install the new shave plate with new carriage bolts

and locking nuts.

7b. Replace the skid shoes if they are worn.

7c. Skid shoe adjustment- place a length of corrugated

cardboard under the shave plate, supporting the

shave plate evenly about 1/4” (0.5cm) above the

ground. Push the skid shoes down against the

ground, then tighten the nuts that secure them.

Auger drive system maintenance

1. Remove the belt cover.

1a. Remove the screw on the right side of the of the

belt cover using a 3/8” wrench.

1b. Squeeze the locking tabs inward and slip

the belt cover up and off of the snow thrower.

2. Tip the snow thrower up onto it’s auger housing.

3. Inspect the auger belt for signs of wear or damage.

4. Disconnect the auger brake spring with a piece of starter

rope (the spring can be reached from the top, with the belt

cover has removed).

5. Apply a film of with lithium grease under the auger brake

arm

6. Work the brake arm back and forth to allow the grease to

spread evenly under the arm.

7. Add a light film of oil to the brake spring.

8. Replace the auger brake return spring.

Figure 2.2

Skid shoe Mounting bolts

! CAUTION! CAUTION

Allow the engine to cool, and drain the fuel and oil from it before starting any main-

tenance procedures.

Figure 2.3

Maintenance

7

Traction drive system maintenance

NOTE: Be careful to keep oil and grease away from the belts and pulleys.

NOTE: Replace any worn or damaged parts discovered during inspection.

NOTE: If a part has failed prematurely, identify and correct the cause of the failure.

1. Loosen the wheel bolts using a 1/2” wrench.

2. If not previously removed, take the belt cover off;

2a. Remove the screw on the right side of the of the

belt cover using a 3/8” wrench.

2b. Squeeze the locking tabs inward and slip

the belt cover up and off of the snow thrower.

3. Tip the snow thrower up onto its auger housing.

4. Inspect the moving parts of the system:

4a. Check the belts for wear or damage.

4b. Check the cables for wear or damage.

4c. Operate the traction clutch control bale; the cable and

clutch should move smoothly.

4d. Check the traction belt tension pulley; it should rotate smoothly and keep adequate tension on the belt.

4e. Check the cross-shaft bearings; wiggle the shafts. There should not be more than .080” (2mm) play in the

shafts.

5. For 3-speed snow-throwers;

5a. Relieve tension from the traction drive belt by drawing-back the tension pulley.

5b. Operate the speed control lever; confirm that the variable-speed pulley moves and returns smoothly.

6. Apply grease to the two drive gears.

7. Apply a light coating of oil to the transmission tension spring.

8. Spray some penetrating oil into the area between any rotating shafts and the plain bushings that they ride in.

9. Lubricate the axles so that the wheels can be removed easily in the future:

9a. Remove the wheels.

9b. Apply a light coating of anti-seize grease to the axle.

9c. Replace the wheels.

9d. Install the wheel bolts and Belleville washers; the outer lip of the washer should taper inward to contact the

outer edge of the axle.

9e. Tip the snow thrower back to its normal operating position.

9f. Tighten the wheel bolts to a torque of 20 in-lbs. (2.25 Nm).

10. Check and adjust the tire pressure to 20psi.

NOTE: The transmission is filled with gear oil and sealed at the factory. It is not intended to be serviced, and

will require no maintenance.

Figure 2.4

70T Bull gear

Drive Belt

Tension Spring

14T Pinion

Gear

! CAUTION! CAUTION

When checking actuating or belt-tensioning mechanisms, do not place your fingers

in an area where they might be pinched by unexpected movement.

MAINTENANCE

8

FINAL

1. Reinstall the belt cover.

2. Spray some penetrating oil into the points of the control cables where the cable core enters the cable housing.

3. Re-fill the crankcase with fresh 5W-30 engine oil, and add a small amount of fresh gasoline to the fuel tank.

4. Test-run the snow thrower, testing all operation and safety features.

5. Prepare the engine for storage;

• Drain or run all of the fuel out of the engine.

• Remove the spark plug and add a small amount of motor oil to the cylinder, then replace the spark plug.

• Turn the crankshaft 3-4 revolutions using the starter rope. Stop when there is tension on the rope, leaving both

valves in the closed position.

TRACTION DRIVE SYSTEM

9

Description of the traction drive system

• A belt transfers power from the engine crankshaft to the input pulley of the transmission.

• A spring-loaded idler pulley keeps the belt under constant tension.

• On the three-speed version, a cable operated variable speed pulley changes the drive ratio to the transmission:

the sheaves of the pulley close or spread to change its effective circumference. The idler pulley automatically com-

pensates for the change in belt tension.

• The transmission is a sealed unit with an internal clutch. The clutch is actuated by a cable attached to the drive

control bale on the handle.

• The transmission drives a 14T pinion gear which turns a 70T bull gear.

• The bull gear turns the axle at a 5:1 ratio from the transmission input shaft speed.

Wheels and Tires

IMPORTANT: The proper inflation pressure is a maximum

20 psi. See Figure 3.1.

Uneven air pressure between the two tires may result in:

• Uneven tire wear

• Irregular drive tracking

• Pulling from one side or the other

NOTE: While it is possible to replace the tires on the

wheels, they are generally serviced as an assembly.

Tire Replacement

1. Loosen the bolts that hold the wheels to the axles using a 1/

2” wrench. See Figure 3.2.

2. Tip the snow thrower forward onto its auger housing.

3. Remove the bolts and slip the wheels off of the axles.

NOTE: The wheels fit onto the axle with a double “D”.

4. On installation, lubricate the axle shaft with anti-seize.

5. Install the bolts and Belleville washers with the outer edge

of the washers tapered in to meet the axle.

Figure 3.1

Air pressure gauge

! CAUTION! CAUTION

If you encounter a snow thrower with

plastic wheels, see Special Reminder

Service Advisory MTD-098.

! CAUTION! CAUTION

Do not overinflate the tires.

Figure 3.2

Wheel bolt

! CAUTION! CAUTION

Allow the engine to cool, then drain

the fuel and oil from the engine before

starting any service procedure.

CHAPTER 3: TRACTION DRIVE SYSTEM

TRACTION DRIVE SYSTEM

10

DRIVE BELT REPLACEMENT: SINGLE-SPEED SYSTEM

1. Remove the belt cover:

1a. Remove the screw on the right side of the belt cover

with a 5/16” wrench or screwdriver. See Figure 3.3.

1b. Squeeze the locking tabs on the belt cover inward while

lifting.

1c. Work the cover from between the engine and

discharge chute

2. Tip the snow thrower forward onto the auger housing.

3. Remove the spring retaining nut from the anchor bolt on the side of the engine frame with a 7/16” wrench.

See Figure 3.4.

4. Disconnect the extension spring that draws the transmis-

sion toward an anchor bolt on the engine frame from the

anchor bolt.

NOTE: Use a length of heavy cord looped around the hook

end of the spring. See Figure 3.5.

Figure 3.3

Screw

Lock tab

! CAUTION! CAUTION

Allow the engine to cool, then drain

the fuel and oil from the engine before

starting any service procedure.

Figure 3.4

Nut

Anchor bolt

Figure 3.5

Starter rope

Extension

spring

TRACTION DRIVE SYSTEM

11

5. Rock the transmission forward to provide the slack needed

to removed the drive belt from the transmission pulley.

NOTE: The auger drive belt must be removed to remove or

install the self-propel drive belt. See Figure 3.6.

6. Slip the auger belt off of the front engine pulley sheave

7. Route the drive belt between the upper and lower pulleys.

8. Replace the drive belt with a new one. Use only the correct

OEM part number belt.

9. Install the new belt by reversing the removal process.

NOTE: If the belt has failed prematurely find the cause and

repair it before installing the new belt

Drive Belt Replacement: three speed drive system

1. Remove the belt cover:

1a. Remove the screw on the right side of the belt cover

with a 5/16” wrench or screwdriver. See Figure 3.7.

1b. Squeeze the locking tabs on the belt cover

inward while lifting.

1c. Work the cover from between the engine and

discharge chute

2. Remove the spring retaining nut from the anchor bolt on the

side of the engine frame with a 7/16” wrench. See Figure 3.8.

3. Disconnect the extension spring that draws the transmis-

sion toward an anchor bolt on the engine frame from the

anchor bolt. See Figure 3.9.

Figure 3.6

traction

drive belt

Auger

pulley

Figure 3.7

Screw

Tab

Figure 3.8

Nut

Anchor bolt

Figure 3.9

Starter rope

Extension spring

TRACTION DRIVE SYSTEM

12

4. Remove the spark plug and insert a 20” piece of starter

rope to act as a piston stop and prevent the engine from

turning.

5. Remove the bolt that holds the auger drive pulley to the

engine crankshaft with a 9/16” wrench. See Figure 3.10.

NOTE: The auger belt drive pulley is a split-sheave design.

6. Slide the outer auger pulley sheave off of the crank shaft

and remove the auger belt. See Figure 3.11.

7. Remove the inner auger pulley sheave, and the spacer that

fits behind it off of the crankshaft. See Figure 3.12.

Figure 3.10

Auger drive pulley

Figure 3.11

Outer sheave

Inner

sheave

Figure 3.12

Spacer

TRACTION DRIVE SYSTEM

13

NOTE: .To replace the drive belt on a three speed drive

system, the speed actuator arm needs to be removed.

8. Loosen the jam nuts that hold the speed control cable to the

bracket on the engine.

9. Adjust the nuts to provide slack in the cable.

10. Disconnect the speed control cable from the actuator arm.

See Figure 3.13.

11. Remove the bow tie clip from the pivot rod.

See Figure 3.14.

12. Pull the pivot rod free from the actuator arm.

13. Remove the actuator arm.

14. Pull the variable speed pulley yoke off of the crankshaft.

See Figure 3.15.

Figure 3.13

Actuator arm

Speed

control

cable

Figure 3.14

pivot rod

Bow tie clip

Figure 3.15

Yoke

TRACTION DRIVE SYSTEM

14

NOTE: A sealed ball bearing and the outer half of the vari-

able speed pulley will come-off with it.

15. Slip the belt off of the crankshaft. See Figure 3.16.

16. Reach from under the snow thrower and pull the belt off of

the transmission pulley.

17. Lift the belt out of the snow thrower. See Figure 3.17.

18. Check the operation of the belt tensioner and variable

speed mechanism while the belt is out of the snow thrower;

See Figure 3.18.

• The moving half (outer sheave) of the variable speed pulley

should slide freely on the splines of the fixed half (inner

sheave).

• The sealed bearing between the outer sheave and the yoke

should spin smoothly.

• The idler pulley on the tensioner arm should spin smoothly.

• The tensioner arm should pivot easily.

19. Install the belt by reversing the removal process.

20. Check the speed control cable adjustment.

See: SPEED CONTROL CABLE REPLACEMENT

21. Reinstall the belt cover before testing the snow thrower.

22. Fully test the traction drive system, the speed control lever, and the auger drive system before returning the

snow thrower to service.

Figure 3.16

Figure 3.17

Inner sheave

Belt

Figure 3.18

Yoke

Bearing

Inner sheave

Outer sheave

TRACTION DRIVE SYSTEM

15

DRIVE ENGAGEMENT CABLE REPLACEMENT

1. Unhook the z-fitting from the drive engagement control bail:

1a. Squeeze the bail to release the right side of the bail

from the handlebar.

1b. Once the right side is released, pivot the bail to unhook

the left side of it from the left handlebar.

1c. With the control bail released from the handlebar, it can

be rotated to release the Z-fitting. See Figure 3.19.

2. Detach the cable mounting block from the left side of the

handle bars. with a large Phillips head screw driver and a

7/16” wrench. See Figure 3.20.

NOTE: On some models, the mounting block was incorpo-

rated in the auger cable and is not a separate part.

3. Cut the cable retaining straps to free the cable. Replace the

retaining straps with new strap when re-installing the cable

4. Tip the snow thrower forward onto it’s auger housing

5. Disconnect the drive cable from the actuator arm on the

transmission. See Figure 3.21.

NOTE: With the top end of the control cable disconnected,

there is enough slack to easily disconnect the spring on the

transmission end of the cable from the arm on the transmis-

sion.

Figure 3.19

Right side:

goes straight in

Left side:

extra hook in the

end of the bail

Figure 3.20

Drive cable bracket

Figure 3.21

Actuator

arm

cable-end spring

TRACTION DRIVE SYSTEM

16

6. Release the cable from the transmission housing by

squeezing the barbs that lock the cable housing into the

bracket on the transmission. See Figure 3.22.

7. Route the cable out of the frame.

8. If the snow thrower has the three speed drive system;

• The ground speed is controlled by the speed selector lever

located on the left side on the upper handle bars.

• In order to change the ground speed the engine needs to be

running and the drive engagement must be released.

• The speed is controlled by a variable-speed pulley system

located in front of the engine.

• Removing the clutch cable of a three speed snow thrower is not

much different than removing the transmission from a single

speed snow thrower.

9. Reinstall the cable in reverse order.

10. Test-run the snow thrower before returning it to service.

Figure 3.22

Cable bracket

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MTD 300 Series Shop Manual

MTD 300 Series Shop Manual

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