Service Manual
MTD Products LLC - Product Training and Education Department
FORM NUMBER 769-01417
9/2004
31AS250-700 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 provide supplemental information to assist the trained technician. Untrained or inexperienced
individuals should seek the assistance of an experienced and trained professional. Read, understand, and follow all
instructions and 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 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. © Copyright 2005 MTD Products
Inc. All Rights Reserved
TABLE OF CONTENTS
General Information ....................................................................................................1
Drive Belt Removal .....................................................................................................1
Chute Removal ...........................................................................................................2
Flail Replacement .......................................................................................................3
Shave Plate Servicing ................................................................................................3
Auger Removal ...........................................................................................................3
Shroud Cover Removal ..............................................................................................4
Engine Removal .........................................................................................................5
Fuel Tank Removal ....................................................................................................5
1
31AS250-700
SNOW-THROWER MODEL 31AS250-700 SERIAL #
1E074B20022
GENERAL INFORMATION
• Single Stage snow thrower
• 4.5 horsepower Tecumseh HSK Air Cooled Two
cycle engine with Electric Start
• To operate you need to use a clean, high quality,
2-cycle oil mixed at a ratio of 50:1. Use if NMMA,
TC-Wll or TC-W3, JASO FB or FASO FC classi-
fied oil is recommended. A 32:1 fuel mix is rec-
ommended if NMMA oil is not available.
NOTE: These materials are prepared for use by
trained technicians who are experienced in the
service and repair of this type of equipment
described in this publication, and are not
intended for use by untrained or inexperienced
individuals. All such individuals should seek the
assistance of an authorized service dealer.
WARNING: Before servicing, repair, or inspect-
ing, disengage all clutch levers and stop engine.
Wait until all moving parts have come to a com-
plete stop. Disconnect spark plug wire and
ground it against the engine to prevent unin-
tended starting.
NOTE: Some procedures require you to tip the
snow thrower up on the front of the auger hous-
ing. If there is fuel in the gas tank, place a piece
of plastic wrap over the gas tank opening and
screw the cap back on the tank tightly. This
should keep the gas from leaking out of the cap
or vent.
During the service of this Snow Thrower there is no
reason to remove the wheel assemblies, other than
complete wheel replacement. The push cap on the
wheels must be replaced when removed.
1. DRIVE BELT REMOVAL
1.1. Remove the (5) screws using a 3/8 socket and
ratchet wrench from the perimeter of the belt
cover and remove the cover for access to the
belt drive assembly.
NOTE: The front screw is shorter than the other
four and is a fine thread. It is necessary that this
screw be used to allow for clearance to the
auger assembly.
1.2. Loosen or remove the ball bearing idler using a
7/16 socket and ratchet wrench. Notice the posi-
tion of the outer washer or belt retainer; the flat
side should be facing up, to allow clearance
Perimeter Screws
31AS250-700 Snow Thrower
2
inside the belt cover. Inspect the bearing for
wear or damage.
1.3. Pressing down on the idler bracket will allow the
brake shoe to lift off the belt and out of the pulley
area to easily roll the belt off the auger pulley
and the engine drive pulley.
1.4. Re-install in reverse order.
NOTE: The Idler arm return springs can be
checked for proper tension and also the engage-
ment cable can be checked for damage and
operation.
2. CHUTE REMOVAL
For replacement of the directional chute, latches must
be opened to remove the chute clamp. Access to the
latches can be gained from the inside rear opening.
NOTE: Removal of the chute is easier than it is
to reinstall. If the shroud cover is to be removed,
it is easier to disassemble the handle and upper
chute and place the clamp on the lower chute
prior to installing the shroud cover.
2.1. Position the chute facing forward and the latches
of the chute will be exposed.
NOTE: There is an upper and a lower latch on
the directional chute clamp.
2.2. Use a long blade screwdriver to access the latches.
Auger Pulley Idler Arm Idler Pulley
Auger Belt Engine Drive Pulley
Brakes shoe stamped into idler arm
Idler Arm
Auger Engagement
Return Spring
Cable and Spring
3
2.3. Using a long blade screwdriver release the
upper and lower latch.
3. FLAIL REPLACEMENT
3.1. Lay the snow-thrower back on the handles to
allow access to the rubber flails.
3.2. Remove the self tapping hex screws attaching
the rubbers flails to the auger assembly.
3.3. Attach new flails in reverse order.
4. SHAVE PLATE SERVICING
The plastic shave plate can also be removed if worn
VIEW FROM BEHIND UNIT UNDER COWLING
Latches
Rubber Flails
and turned around.
5. AUGER REMOVAL
5.1. Using a 1” socket, remove the auger pulley.
This is a left hand threaded nut. Remove clockwise.
Shave Plate
Auger Pulley
4
5.2. Remove the bearing housing screws using a
3/8” socket.
5.3. Remove the auger bolt on the right side of the
housing using a 7/16” socket and ratchet.
5.4. Using a drift punch or 3/8” 6” extension tap on
the end of the auger shaft from the right side,
driving the axle shaft out of the right hand bear-
ing and thereby pushing out the bearing and
bearing backup washer out the left side.
The auger can now be inspected for wear and or
breakage of welds. If not damaged, replace in reverse
order.
6. SHROUD COVER REMOVAL
6.1. Remove the upper chute and the chute handle
from the lower chute.
Bearing Housing Cover
LEFT SIDE
RIDE SIDE
Auger Bolt
Slider the auger to left pushes out bearing
5
6.2. Using a 3/8” socket remove the three screws
securing the front of the housing to the auger
housing.
6.3. Remove the four bolts (two on each side) secur-
ing the sides of the shroud cover housing to the
sides of the auger housing.
6.4. MORE INSTRUCTIONS TO COME
7. ENGINE REMOVAL
8. FUEL TANK REMOVAL
Shroud Screws
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