Professional Shop Manual
300 Series Snow Thrower
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 provid e su pp lem ental information to assist the trained technician. Untrained or inexperienced individuals should seek the assistance of an experienced and tr ained professional. Read, understand, a nd follow all
instructions and use common sense when working on power equipment. This includes the contents of the product’s Operators 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 a nd accura te as possib le at the time of publica tion. 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.
© Copyright 2009 MTD Products Inc. All Rights Reserved
MTD Products Inc - Product Training and Education Department
FORM NUMBER - 769-05547
11/2009
Table of Contents
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
I
II
INTRODUCTION
CHAPTER 1: INTRODUCTION
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! CAUTION
! WARNING! WARNING
! DANGER! DANGER
NOTE: “NOTE” is used to point-out helpful information that may not fit as a step in a procedure.
1. Numbered steps
1a. Sub steps
the actions required to complete a step.
• Bullet points: Indicate sub-steps or points of interest, without implying order or relative importance.
will be lettered and nested within steps. Two or more sub steps may be combined to describe
CAUTION: Indicates a potentially hazardous situation that, if not avoided, ma y result in
minor or moderate injury. It may also be used to alert against unsafe practices.
WARNING: Indicate s a poten tia lly haza rd ous situat io n tha t, if not a voide d, could r esult
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.
indicate specific things that should be done, and the orde r in whic h th ey sh ou ld be do ne.
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.
1
INTRODUCTION
Safety
This Service Manual is meant to be used along with the Operator’s Manual. Read the Operator’s Manual and familiarize yourself with the safety and operational instructions for the equipment being worked on . K eep a co py 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
Protective gloves
Armored footwear
Hearing protection
Chemically resistant gloves
Respirator
Appropriate tinted eye protection
while working around any machinery
where necessary
when working around any machinery
in noisy environments
when working with chemicals or solvents
when working with chemical or solvents
when cutting or welding
! CAUTION! CAUTION
! CAUTION! CAUTION
! WARNING! WARNING
! WARNING! WARNING
Fame resistant headgear, jacket, chaps
• 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 monoxide 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.
2
when cutting or welding
! CAUTION! CAUTION
! CAUTION! CAUTION
! DANGER! DANGER
INTRODUCTION
Fasteners
• The fasteners used on the equipment described in this manual, and the engine that powers it are a combination of metric and fractional inch. For this reason , wrench sizes are frequently identified in the text, and measurements 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
• T orque spec ifications may be noted in the p art 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 procedure 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.
3
INTRODUCTION
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
Figure 1.0
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 carr y
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
• 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 p arts 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.
reads as follows:
MTD Products LLC www.mtdproducts.com
P.O. Box 368022
Cleveland, OH 44136
Telephone: (800) 800-7310
4
Maintenance
CHAPTER 2: MAINTENANCE
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-
! CAUTION! CAUTION
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.
nance or service procedures.
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 confirm 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
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 maintenance 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 replacement of the complete transmission and auger shaft assembly.
5. Inspect the impeller;
prevent damage to the auger trans-
Shear Pins
Figure 2.1
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 for eig n ob je cts jamm ed beh in d th e imp el-
ler.
NOTE: The typical customer complaint will be that the augers turn, but the snow just oozes out of the discharge chute.
5
MAINTENANCE
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.
Skid shoe Mounting bolts
Figure 2.2
Auger drive system maintenance
Allow the engine to cool, and drain the fuel and oil from it before st artin g any main-
! CAUTION! CAUTION
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.
tenance procedures.
Figure 2.3
7. Add a light film of oil to the brake spring.
8. Replace the auger brake return spring.
6
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;
Maintenance
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 shaf t s. Ther e sh ould not be more th an .080” ( 2mm) play in the
shafts.
When checking actuating or belt-tensioning mechanisms, do not place your fingers
! CAUTION! CAUTION
5. For 3-speed snow-throwers;
5a. Relieve tension from the traction drive belt by drawing-back the tension pulley.
in an area where they might be pinched by unexpected movement.
70T Bull gear
14T Pinion
Gear
Figure 2.4
Drive Belt
Tension Spring
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 Bellevil le washers; the outer lip of the washer should taper inwar d 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.
7
MAINTENANCE
FINAL
1. Reinstall the belt cover.
2. Spray some penetra ting oil in to the po ints 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 crankshaf t 3-4 revolutions using the st arter rope. Stop when there is tension on the rope, leaving both
valves in the closed position.
8
TRACTION DRIVE SYSTEM
CHAPTER 3: TRACTION DRIVE SYSTEM
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 op er a ted var i ab le speed pulley changes the drive ratio to the transmission:
the sheaves of the pulley close or spread to change its effe ctive circumference. The idle r pulley automatically compensates 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.
Air pressure gauge
Uneven air pressure between the two tires ma y result in:
• Uneven tire wear
• Irregular drive tracking
• Pulling from one side or the other
If you encounter a snow thrower with
! CAUTION! CAUTION
NOTE: While it is possible to replace the tires on the
wheels, they are generally serviced as an assembly.
plastic wheels, see Special Reminder
Service Advisory MTD-098.
Do not overinflate the tires.
! CAUTION! CAUTION
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.
Allow the engine to cool, then drain
! CAUTION! CAUTION
the fuel and oil from the engine before
starting any service procedure.
Figure 3.1
Wheel bolt
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 3.2
9
TRACTION DRIVE SYSTEM
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 cove r inward while
lifting.
1c. Work the cover from between the engine and
discharge chute
Screw
Allow the engine to cool, then drain
! CAUTION! CAUTION
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 transmission toward an anchor bolt on the engine frame from the
anchor bolt.
the fuel and oil from the engine before
starting any service procedure.
Nut
Anchor bolt
Lock tab
Figure 3.3
Figure 3.4
10
NOTE: Use a length of heavy cord looped around the hook
end of the spring. See Figure 3.5.
Starter rope
Extension
spring
Figure 3.5
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 re moved 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
TRACTION DRIVE SYSTEM
7. Route the drive belt between the upper and lower pulleys.
8. Replace the drive belt with a new one. Use on ly th e corr ect
OEM part number belt.
9. Install the new belt by reversing the removal process.
NOTE: If the belt has failed prematurely find the cause an d
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
traction
drive belt
Auger
pulley
Figure 3.6
Screw
Tab
2. Remove the spring retaining nut from the a nchor 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 transmission toward an anchor bolt on the engine frame from the
anchor bolt. See Figure 3.9.
Starter rope
Extension spring
Figure 3.9
Figure 3.7
Nut
Anchor bolt
Figure 3.8
11
TRACTION DRIVE SYSTEM
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.
Auger drive pulley
Figure 3.10
Inner
sheave
7. Remove the inner auger pulley sheave, and the sp acer th at
fits behind it off of the crankshaft. See Figure 3.12.
Outer sheave
Figure 3.11
Spacer
Figure 3.12
12
TRACTION DRIVE SYSTEM
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.
Actuator arm
Speed
control
cable
Figure 3.13
pivot rod
Bow tie clip
14. Pull the variable speed pulley yoke off of the crankshaft.
See Figure 3.15.
Figure 3.14
Yoke
Figure 3.15
13
TRACTION DRIVE SYSTEM
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.
Figure 3.16
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.
Belt
Inner sheave
Figure 3.17
Inner sheave
Outer sheave
Yoke
• The tensioner arm should pivot easily.
19. Install the belt by reversing the removal proces s.
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.
14
Bearing
Figure 3.18
DRIVE ENGAGEMENT CABLE REPLACEMENT
TRACTION DRIVE SYSTEM
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 incorporated in the auger cable and is not a separate part.
3. Cut the cable retaining straps to free the ca ble. Replace the
retaining straps with new strap when re-installing the cable
Right side:
goes straight in
Left side:
extra hook in the
end of the bail
Figure 3.19
Drive cable bracket
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 transmission.
Figure 3.20
Actuator
arm
cable-end spring
Figure 3.21
15
TRACTION DRIVE SYSTEM
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 se lec tor leve r
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.
Cable bracket
Figure 3.22
16
SPEED CONTROL CABLE REPLACEMENT
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 3.23.
1b. Squeeze the locking tabs on the belt cover inward
while lifting the cover.
1c. Work the cover from between the engine and d ischarge
chute
2. Remove the jam nut that holds the speed control cable
housing to the cable bracket on the engine. Use a pair of 1/
2” wrenches. See Figure 3.24.
TRACTION DRIVE SYSTEM
Screw
Lock tab
Figure 3.23
Bracket
Cable
3. Release the barrel on the end of the speed control cable
from the arm that moves the variable speed pulley.
See Figure 3.25.
4. Pull the lower end of the cable free of the snow thrower.
Figure 3.24
Figure 3.25
17
TRACTION DRIVE SYSTEM
5. Remove the three phillips head screws that hold the cover
on the speed control housing. See Figure 3.26.
Speed control
housing
Figure 3.26
6. Carefully remove the speed control cable from the speed
control housing. See Figure 3.27.
• Lift the top of the cable out of the recess in the speed control
housing.
• Release the barrel from the keyhole slot in the speed control
lever.
7. Cut any cable ties holding the speed control cable to the
handlebars, and remove the cable.
8. Install the replacement cable by reversing the steps used to
remove the old cable.
9. Adjust the replacement cable using the jam nuts at the
engine end cable bracket; See Figure 3.28.
9a. Disconnect and ground the spark plug wire.
9b. Set the speed control lever for position #1.
9c. Slowly pull the starter rope.
9d. Adjust the jam nuts so that there is 1/8” (3.2mm) of
clearance between the speed control arm and the
auger belt.
Speed control
cable
Figure 3.27
Auger belt
Speed control
arm
10. Install the belt cover , connect the sp ark plug wire, and fully
test run the snow thrower drive system before returning it to
service.
18
1/8” gap
Figure 3.28
TRANSMISSION REMOVAL
1. Disconnect the z-fitting from the drive control on the handle bar.
2. Detach the cable mounting block from the left side of the
handle bars.
3. Cut the cable retaining straps that secure the cable to the
handle bars.
4. Tip the snow thrower forward onto it auger housing.
5. Remove the nut on the spring anchor bolt.
6. Release the cable from the transmission housing with needle nose pliers
7. Engage the transmission to prevent the shaft from spilling.
See Figure 3.29.
TRACTION DRIVE SYSTEM
Engage transmission
Figure 3.29
8. Remove the cotter pins from each end of the transmission
out-put shaft. See Figure 3.30.
NOTE: A roll pin holds the pinion gear to the transmission
out-put shaft.
9. Drive the roll pin out using a 1/8” flat nose drift.
See Figure 3.31.
10. Slide the pinion gear towards the transmission.
11. Apply grease to the shaft before reinstalling the pinion gear .
NOTE: When reinstalling the pinion gear position it so that
the gear hub is towards the frame.
Out-put shaft
Cotter pin
Figure 3.30
Driving roll pin out
Figure 3.31
19
TRACTION DRIVE SYSTEM
12. Slide the bearing and shim out from each side of the frame.
See Figure 3.32.
13. Inspect the bearings for wear or damage.
NOTE: Apply a coating of grease to the shaft and bearing
before reassembling.
14. Move the transmission to the left and pivot it forward to
remove it from the frame.
15. Reverse the removal process to install a new transmission.
• Lubricate the contact points where the transmission out put
shaft ride on a bushing.
Washer
Bearing
Out-put shaft
• Use a grease suitable for operation in cold temperatur es.
• Apply anti-seize compound to the contact point between the
pinion gear and the transmission out put shaft.
• Secure the transmission to the frame using new 1/8” x 1.0” cotter pins.
16. Test the operation of the driv e system before returning the snow thrower to service.
Figure 3.32
20
TRACTION DRIVE SYSTEM
TRANSMISSION INTERNALS
NOTE: the transmission has been broken down to satisfy professional curiosity, this information is not
intended to suggest that the transmission is to be serviced. If you see any of these part s in the course of working on a 300-series snow thrower, you have done something wrong.
Cone hub clutch
• The Cone hub clutch plates are tapered to fit into the tapper on
the helical gear.
• The clutch plates are engaged to the transmission out put shaf t
by 1/8” X 3/4” dowel pin. The dowel pins are position through
holes in the output shaft and the within a key hole in the cone
clutch plate. See Figure 3.33.
Bronze helical gear See Figure 3.34.
• The Helical gear is tapered on each side to allow the clutch
plates to fit into it when the drive is engaged.
Clutch disc Bronze gear
• When the transmission is at rest it is in the neutral position.
• When the drive is engaged: a cam lever pulls the cone hub
clutch plates towards each other.
• The bronze gear is driven by the worm gear on the input shaft.
• The clutch plates are tied to the output shaft by pins; when the plates are driven, they turn the output shaft.
• When the drive control is released a wave washer pushes the clutch plates apart and releasing the bronze gear
gear.
NOTE: The internal parts of the transmission are spread out for this picture. This is the only place that these
parts should be viewed, See Figure 3.35.
Wave washer
Figure 3.33
Figure 3.34
Figure 3.35
21
TRACTION DRIVE SYSTEM
22
AUGER SYSTEM
CHAPTER 4: AUGER SYSTEM
System Description
• The auger and impeller are driven by a belt from the engine crankshaft.
• An idler pulley is drawn against the belt when the control bale is engaged.
• The belt then drives a large pulley on the back of the impeller shaft.
• The impeller shaft enters the rear of the auger housing, driving the impeller through a roll pin.
• The impeller shaft continues forward to a “T” shaped worm-gear transmission.
The transmission drives the auger shaft.
• The auger system uses four individually stamped flights that draw the snow inward and into the impeller.
• The impeller then throws the snow out of the discharge chute with more force than auge rs alone could generate.
Auger belt removal
1. Remove the belt cover:
1a. Remove the screw on the right side of the belt cover
with a 5/16” wrench or screw driver.
1b. Squeeze the locking tabs on the belt cover inward
while lifting. See Figure 4.1.
1c. Work the cover from between the engine and disch arge
chute
Allow the engine to cool, then drain
! CAUTION! CAUTION
2. Tip the snow thrower forward onto its auger housing.
3. Remove the belt keeper located under the auger pulley.
Use a 1/2” wrench. See Figure 4.2.
the fuel and oil from the engine before
starting any service procedure.
Screw
Lock tab
Figure 4.1
Auger belt
Auger pulley
Belt keeper
Figure 4.2
23
AUGER SYSTEM
4. Disconnect the auger control cable from the control bail.
This will allow enough slack in the auger control cable to
free the auger belt from the engine pulley. See Figure 4.3.
5. Use your thumb to pull the auger brake far enough away
from the auger pulley to slip the belt off of the pulley.
See Figure 4.4.
Bail
Cable
Figure 4.3
Auger pulley Brake
Figure 4.4
6. Remove the belt from the engine pulley and idler pulley.
See Figure 4.5.
7. Slip the belt out of the snow thrower.
NOTE: If the belt has failed prematurely, identify and repair
the cause of the failure before continuing.
NOTE: Use only the correct OEM belt.
8. Install the belt by reversing the removal process.
9. Check and adjust the cable bracket any time the auger belt
or auger cable have been replaced;
9a. With the auger control bale engaged, the spring that
connects the cable to the brake arm should be
stretched a total of .080”.
9b. With the auger control bale released, the cable should
be slack.
9c. Loosen the bracket bolts and slide the bracket to tighten or loosen the cable.
10. Install the belt cover and test the operation of all features of the snow thrower before returning it to service.
Engine pulley
Auger belt
Figure 4.5
24
Auger control cable replacement
AUGER SYSTEM
1. Remove the belt cover as described in the “BELT
REMOVAL” section of this chapter.
2. Slip the cable off of the cable guide pulley located on the
left side of the frame. See Figure 4.6.
NOTE: It may be necessary to loosen the screw that holds
the cable guide pulley using a 3/8” wrench.
3. Use the slack created by the previous step to un hook the Zfitting at the top end of the cable from the auger control ba il.
See Figure 4.7.
4. Cut the cable ties that hold the cables to the handle bars.
Cable
Cable guide
Figure 4.6
Auger control bail
Z-fitting
Auger control cable
NOTE: On three-speed models, the cable passes through
the speed control housing on the handleb ar s.
5. Remove the phillips head screws that hold the two halves of
the speed control housing together. See Figure 4.8.
Figure 4.7
Speed control housing
Figure 4.8
25
AUGER SYSTEM
6. Carefully slip the auger control cable out of the speed control housing. See Figure 4.9.
7. On single-speed models, remove the nut and bolt that hold
the cable bracket to the handlebar. See Figure 4.10.
8. Slip the auger control cable out of the brac ket .
Auger control
cable
Figure 4.9
Inset:
cable
bracket
9. Pull the cable upward from the opening created by removing the belt cover.
10. From above, the spring on the end of the cable can be
maneuvered to unhook it from the auger pulley brake arm
(the auger belt idler pulley is attached to the brake arm).
See Figure 4.11.
Auger control
cable
Figure 4.10
Cable-end spring
Eyelet in
brake arm
Figure 4.11
26
AUGER SYSTEM
1 1. Unbolt the auger cable control bracket from the right side of
the frame using a 3/8” wrench.
12. Release the auger control cable from the bracket on the
right side of the frame. See Figure 4.12.
13. Install the replacement cable by reversing the removal process.
14. Check and adjust the cable bracket any time the auger belt
or auger cable have been replaced;
14a. With the auger control bail engaged, the spring that
connects the cable to the brake arm should be
stretched a total of .080”.
14b. With the auger control bail released, the cable should
be slack.
14c. Loosen the bracket bolts and slide the bracket to tighten or loosen the cable.
15. With the belt cover installed, test the op eration of all fe ature s of the sn ow thrower be fo re retu rning it to se rvice.
Disconnecting
the cable
Figure 4.12
Cable bracket
27
AUGER SYSTEM
Auger housing Removal
NOTE: Auger housing removal is necessary for any repairs to the auger, impeller, or auger transmission.
1. Remove the auger belt following the instructions in the
AUGER BELT REMOVAL section
2. Loosen (do not remove) the bolt that holds the cable guide
pulley to the frame.
3. Disconnect the auger control cable from the control bail on
the handlebar.
4. Disconnect the spring end of the auger control cable from
the auger pulley brake arm. See Figure 4.13.
NOTE: The spring is most easily disconnected from the
brake arm by pivoting the spring upward.
5. Slip the auger belt off of the engine and idle pulleys.
6. Unbolt the auger housing from the engine and drive unit:
6a. Loosen, but do not remove the bottom two screws
6b. Remove the top two screws.
6c. Tilt the engine and drive unit back; it will separate at the
top. See Figure 4.14.
6d. Support the snow thrower with 4X4s or similar solid
braces.
Auger control
cable
Eyelet on
brake arm
Figure 4.13
Remove
6e. Remove the bottom two screws carefully move the
auger housing forward to remove it.
7. Re-install the auger housing by reversing the steps used to remove it.
8. Test all features of the snow thrower before returning it to service.
LOOSEN
Figure 4.14
28
Auger Housing disassembly: Pulley removal
1. Remove the bolt that holds the auger pulley to the impeller
shaft using a 1/2” wrench. See Figure 4.15.
NOTE: The auger brake may need to be moved over briefly
to clear the pulley.
2. Pull the auger brake clear of the pulley.
3. Inspect the brake spring idler bracket and idler pulley for
wear or damage. See Figure 4.16.
AUGER SYSTEM
Auger pulley
Figure 4.15
Figure 4.16
29
AUGER SYSTEM
Auger housing disassembly: Impeller shaft bearing replacement
1. Separate the auger housing from the engine drive unit and remove the pulley.
2. Remove the two nuts that secure the bearing housing,
using a 1/2” wrench. See Figure 4.17.
3. Slide the bearing and spacer off of the impeller shaft to
inspect for wear. See Figure 4.18.
Bearing housing
Nuts
Figure 4.17
Spacer
4. The auger shaft is supported by bearings at each end.
The bearings are fixed in housings.
• Remove the hex cap screws that hold the auger shaft bearing housings on each side of the auger housing with a 1/2”
wrench. See Figure 4.19.
NOTE: Support the auger assembly while removing the
bushing housing screws
Bearing
Figure 4.18
30
Figure 4.19
5. Slide the auger and impeller assembly from the auger
housing as one assembly See Figure 4.20.
6. Slide the bushing housings and bearings off of the auger
shafts.
NOTE: Before re-installing, apply grease to the bushings
and impeller shaft.
NOTE: Inspect the auger shaft and bushings for wear.
AUGER SYSTEM
Figure 4.20
31
AUGER SYSTEM
Auger housing disassembly: flight removal
There are four individual auger flies. The flies draw snow inward to the impeller. If any one flight is damaged, it can be
replaced individually.
1. Remove the auger shaft assembly, complete with the auger
transmission, impeller shaft, and impeller. See Figure 4.21.
Flights
Figure 4.21
2. Remove the auger shaft bearings and washers.
See Figure 4.22.
3. Remove the bow tie clips and shear pins that transfer
power to the flights from the auger shaft.
4. Slide the flights off of the auger shaft
IMPORTANT: Keep track of the spacers in between the
flights; replace them if they show signs of wear.
Bearing housing
Washer
Figure 4.22
32
NOTE: There are right hand left hand flights.
See Figure 4.23.
• The flights are stamped “L” and “R” to indicate their positio n
as seen from the point of view of the person operating the
snow thrower.
• The identifying “L” and “R” have been highlighted for clarity
in this illustration.
• There are 2 L-flights and 2 R-flights on each machine.
5. When correctly installed on the auger shaft, the front inside
edge of the flights will form a letter “A”.
If they form a letter “V”, the flights have been switched leftto-right. See Figure 4.24.
AUGER SYSTEM
Figure 4.23
A
Figure 4.24
33
AUGER SYSTEM
Auger Housing disassembly: impeller brake replacement
1. The idler pulley that applies tension to the auger belt can be
reached for removal by simply taking-off the belt cover.
• An idler pulley is mounted to an arm that is pulled by the
auger control clutch cable.
• The other end of the arm works as a brake, against the pulley that turns the impeller shaft.
• When that cable is pulled, the idler pulley tightens the belt,
engaging the impeller and auger.
• When the cable is released, a spring pulls the idler pulley
away from the belt and draws the brake arm into the groove
of the pulley that turns the impeller shaft.
2. Use a pair of 9/16” wrenches to remove the pulley and
spacer. This is easy on single-speed snow throwers.
See Figure 4.25.
3. Remove the variable speed pulley control arm as described
in the DRIVE SYSTEM section of this manual.
See Figure 4.26.
Idler
pulley
Cable-end
spring
Brake arm
Figure 4.25
• On three-speed snow throwers, the arm that moves the
variable speed cover must also be removed.
• The arm over-hangs the pulley, blocking its removal.
4. If the brake arm is to be removed, the auge r dr ive pulle y
must come off first.
4a. Separate the auger housing from the engine and drive
unit.
4b. Remove the bolt that holds the auger pulley to the
auger shaft using a 1/2” wrench. See Figure 4.27.
NOTE: The auger brake may need to be moved over briefly
to clear the pulley.
4c. Pull the auger brake clear of the pulley.
4d. Remove the pulley.
Figure 4.26
5. There are two holes in the impeller . Rot ate the impeller to a
position where one of those holes allows wrench access to
the nut on the brake arm pivot bolt.
34
Figure 4.27
6. Remove the brake arm; use a 15/16” wrench on the head of
the brake arm pivot bolt, and a 9/16” socket to reach
through the hole in the impeller. See Figure 4.28.
7. As the brake arm comes free of the auger housing, there
will be slack in the brake spring.
8. Unhook the brake spring from the brake arm.
9. Instal the brake arm by reversing the removal process.
Lube the contact point between the brake arm an d the pivot
bolt with white lithium or grease or low temperature synthetic grease.
AUGER SYSTEM
Brake spring Brake arm
Pivot bolt
Figure 4.28
35
AUGER SYSTEM
Auger housing disassembly: Impeller removal
1. Remove the auger shaft assembly, complete with the auger
transmission, impeller shaft, and impeller. See Figure 4.29.
Description:
• The impeller is fastened to the impeller shaft by two roll
pins: one in front of the impeller, and one behind it.
• The front roll pin can be reached easily once the impeller
shaft is out of the snow thrower.
• The rear roll pin is recessed into the back of the impeller.
Wear eye protection whenever strik-
! CAUTION! CAUTION
2. Drive out the spiral pin located in front of the impeller using
a 1/4” pin punch. See Figure 4.30.
NOTE: Use the correct size and type of punch.
• If an under or over size punch is used damage to the spiral
roll pin or shaft can occur.
• A pointed punch will spread the roll pin, binding it in the
hole.
3. Slide the impeller forward to reach the rear roll pin.
4. Drive out the spiral pin located behind the impeller using a
1/4” pin punch. See Figure 4.31.
5. Install the impeller by reversing the steps used to remove it.
ing tools are used.
Figure 4.29
Front roll-pin
Impeller shaft
Impeller
Figure 4.30
Impeller
Impeller shaft
Rear roll pin
36
Figure 4.31
Auger Transmiss ion
NOTE:
NOTE: The auger transmission on this model is generally
replaced as a complete unit. See Figure 4.32.
• The complete transmission assembly is relatively inexpensive.
• All parts are available, but they are not described in the
Illustrated Parts List.
• Circumstances that may merit rebuilding an auger transmission:
AUGER SYSTEM
-The damage may be minimal
-The shop may repair lightly damaged transmissions during
slack times, so they have rebuilt transmissions on-hand.
-If complete transmissions are on back-order, but parts are available, a repaired transmission will work.
-Keeping some parts on the shelf gives shops the ability to make rep airs with minimal investment in inventory.
Figure 4.32
Transmission Parts
Description Part # Quantity
Housing- right side 918-0123 1
Housing- left side 918-0124 1
Screw 1/4”-20 710-0624 5
22” Auger axle (shaft) 711-04286 1
24” Auger axle (shaft) 711-04285 1
Hi-pro key 3/16” x 5/8” 914-0161 1
Dowel pin 715-04021 1
Worm (impeller) shaft 917-04164 1
Helical bronze gear 0-T 917-0528A 1
Thrust collar 718-04071 1
Plug 721-0325 1
Oil seal 721-0327 1
Flat washer, 3/4” I.D. 936-0351 2
Flat washer, 1/2” I.D. 736-3084 1
Flange bearing, 3/4” I.D. 741-0662 1
Flange bearing, 1/2” I.D. 741-0663 1
37
AUGER SYSTEM
NOTE: There is a lube port on the top of the transmission.
See Figure 4.33.
• The transmission contains Alvania EP grease (part numb er
737-0168A, 8 oz. tube), though it should not need to be refilled in normal operation.
NOTE: The components of the gear box are:
• The impeller shaft with a worm gear.
• 20T helical gear
• A flange bearing and thrust bearing
positioned behind the worm gear
• .25” OD x 1.25” LG dowel pin
• Oil seal towards the rear of the gear box
Figure 4.33
Housing halves
Thrust
collar
bearing
Seal
Auger shaft
Bronze gear and key
Figure 4.34
Washers
Bearing
Impeller shaft /
Worm gear
38
Chute
1. The chute assembly is easily removed from the auger
housing using a 7/16” wrench. It may be ne cessary to reach
into the auger housing to hold the carriage bolts in place
during removal and installation of the chute. See Figure
4.35.
2. The upper chute may also be separated from the chute
base by releasing the collar. See Figure 4.36.
AUGER SYSTEM
Figure 4.35
Upper chute
Collar
• The collar fits in a specific orientation with the upper chute.
• The collar has a wavy lip that engages a detent spring on
the chute base. See Figure 4.37.
Chute
base
Figure 4.36
Detent spring
.
Figure 4.37
39
AUGER SYSTEM
40
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