MTD C series Install guide

Professional Shop Manual
“C” and “D” Series Mowers
MTD Products Inc - Product Training and Education Department
FORM NUMBER - 769-07008
06/2011
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.
© Copyright 2010 MTD Products Inc. All Rights Reserved

I
Chapter 1: Introduction
About the text format ..........................................................................................1
Safety................................................................................................................. 2
Fasteners ...........................................................................................................3
Assembly Instructions ........................................................................................3
The “C” Series Mower ........................................................................................4
The “D” Series Mower ........................................................................................4
Understanding Model and Serial Numbers ........................................................5
Maintenance chart ..............................................................................................6
Fastener Tightening Torques .............................................................................6
Chapter 2: Blade and Belt
Blades ................................................................................................................ 7
Blade Removal ...................................................................................................8
Blade Sharpening .............................................................................................10
Belt Removal 1....................................................................................................1
Belt Replacement .............................................................................................14
Chapter 3: Controls and Cables
Engine Control Cable....................................................................................... 17
Drive Control Housing Assembly ......................................................................19
Drive Control Housing Removal and Disassembly ...........................................20
Drive Clutch Control Cable Removal and Replacement: ................................. 25
Drive Speed Control Cable Removal and Replacement:................................. 26
Chapter 4: Deck and transmission
Trail Shield .......................................................................................................27
Side Discharge Door / Mulch Plug ..................................................................28
Deckwash Fitting ..............................................................................................30
Rear Grass Door ..............................................................................................31
Front Wheels ....................................................................................................33
Front Axle .........................................................................................................36
Front Axle Cover ..............................................................................................39
Handlebars .......................................................................................................40
Transmission and Rear Axle Inspection ...........................................................41
Transmission and Rear Axle Removal .............................................................42
Transmission and variable speed pulley.......................................................... 45
Rear baffle removal ..........................................................................................49
Transmission Internal Workings....................................................................... 52
Table of Contents

II

Introduction
1
Professional Service Manual Intent: This manual is intended to provide service dealers with repair and overhaul
procedures for the “C” and “D” series mowers.
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:
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.
! CAUTION! 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! WARNING Indicates a potentially hazardous situation that, if not avoided, could result in death or
serious injury.
! DANGER! 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.
CHAPTER 1: INTRODUCTION

C and D series mowers
2
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. 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 when working 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
! WARNING! WARNING
! CAUTION! CAUTION • 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 seri-
ous 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 monox-
ide 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.
! DANGER! DANGER
! CAUTION! CAUTION

Introduction
3
Fasteners
• The fasteners used on the equipment described in this manual, and the engine that powers it are a combi-
nation 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 releas-
able 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 summa-
rized 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-refer-
ence guide as well as a step-by-step procedure guide that does not require the user to hunt for informa-
tion.
•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.

C and D series mowers
4
The “C” Series Mower
The “C” series mower is a 21” (53cm) platform intro-
duced for the 2011 season. “C” series refers to the 5th
character in the model number. See Figure 1.1.
• Rear wheel drive with variable speed transmis-
sion.
• Drive control for the Troy-Bilt version is by a
unique two-lever clutch control with a 4-position
speed selector.
• The deck is designed to be used as a rear dis-
charge, side discharge, or mulching mower,
easily reconfigured by the customer.
• Like the A and B series mowers, the wheels
and drive system of the C and D series mowers
are carried by plastic housings that mount to
the front and rear of the deck.
• A single lever sets mowing height.
• 8” (20cm) front wheels and rear wheels
The “D” Series Mower
The “D” series mower is a high wheel version of the
“C” series mower. See Figure 1.2.
• Rear wheel drive with variable speed transmis-
sion.
• Drive control for the Troy-Bilt version is by a
unique two-lever clutch control with a 4-position
speed selector.
• The deck is designed to be used as a rear dis-
charge, side discharge, or mulching mower,
easily reconfigured by the customer.
• Like the A and B series mowers, the wheels
and drive system of the C and D sereis mowers
are carried by plastic housings that mount to
the front and rear of the deck.
• A single lever sets mowing height.
• 8” (20cm) front wheels and 11” (28cm) rear wheels
The C and D series mowers used in this manual are branded “Troy-Bilt TB330XP” and “Troy-Bilt TB350XP”. The
decks are grey with red controls and labels. They are powered by Briggs&Stratton 175cc OHV engines. These mow-
ers may be built in a variety of brands powered by a variety of engines. When ordering parts, identify the mower by
the 11-digit model number and 11-digit serial number.
NOTE: Use only the correct OEM parts when making repairs to the mower or its engine.
Figure 1.1
Inset: bail, clutch,
speed control
Model: 12AKC39B011
Figure 1.2
Model: 12AKD39B011
Inset: bail, clutch
speed control

Introduction
5
Understanding Model and Serial Numbers
A sample model number of an “C” series mower is 12AKC39B011. See Figure 1.3.
The break down of what the model number means is as follows:
• 12 . . . . . . . . . . . . . . . . indicates that this is a self propelled mower
• . . .A . . . . . . . . . . . . . . indicates the sales revision
• . . . . . K . . . . . . . . . . . . indicates 4-speed variable drive with recoil start
• . . . . . . . C . . . . . . . . . indicates rear-wheel drive and wheel size
• . . . . . . . . . 3 . . . . . . . . indicates single lever height adjustment and grass discharge modes.
• . . . . . . . . . . 9B . . . . . . indicates the engine
• . . . . . . . . . . . . . . 011 . indicates the brand or retailer
The serial number is 1L210K30336. The serial number reads as follows:
• 1 . . . . . . . . . . . . . . . . . engineering level
• . L . . . . . . . . . . . . . . . . month of production (A= Jan. B= Feb. C= Mar. D= April...J = Dec.)
• . . 21 . . . . . . . . . . . . . . day of the month
• . . . . .0. . . . . . . . . . . . . last digit of the year, repeats every decade
• . . . . . . K . . . . . . . . . . . plant it was built in (K = Tupelo MS)
• . . . . . . . 3 . . . . . . . . . . assembly line number
• . . . . . . . . 0336 . . . . . . sequence number
Technical and service information is available to our company authorized service center personnel through our com-
pany corporate offices, regional parts distributors and regional service center field support personnel. Please contact
the Central Service Distributor in your area or our contact our corporate offices directly for further service information.
MTD Products LLC
P.O. Box 368022
Cleveland, OH 44136
Telephone: [phone]
www.mtdproducts.com
Figure 1.3

C and D series mowers
6
Maintenance chart
NOTE: Refer to the engine manufacturer’s manual #769-03354A for complete engine service information.
Maintenance item Each use Each 25 hrs. use Each 50 hrs. use
Check engine oil *
Check air filter *
Check for loose/bent blade *
Check & gap spark plug Replace if worn *
Check cooling fins After prolonged storage
Check/clean spark arrestor *
Change oil * and before prolonged storage
Change air filter *
Note on air filter Air filter and pre-filter life vary dramatically with operating conditions
Drain or preserve fuel Before prolonged storage
Fog or lube cylinder Before prolonged storage
Rotate engine to TDC Before prolonged storage
Fastener Tightening Torques
Description U.S. Measurement Metric
Blade Bolt 450-600 in-lb. 50-70 Nm
Wheel nuts 130-170 in-lb. 12-18 Nm
Height adjuster link shoulder screws 45-50 in-lb. 6-7 Nm
Front axle retainers 40-50 in-lb. 3.5-4.5 Nm
Front axle cover 30-40 in-lb. 3.5-4.5 Nm
Rear baffle 30-40 in-lb. 3.5-4.5 Nm
Rear axle lower bracket 30-40 in-lb. 3.5-4.5 Nm
Transmission input pulley nut 100-160 in-lb. 12-18 Nm
Engine mount bolts 20-25 ft-lb. 28-34 Nm
Transmission cover bolts 15-20 in-lb 1-2 Nm
Lower belt cover bolts 45-50 in-lb. 6-7 Nm
Deckwash bolt 45-50 in-lb. 6-7 Nm

Blade and Belt
7
Blades
The condition of the blades will greatly effect the quality of the cut.
The blades should be sharpened and balanced after every 10 hours of cutting, or when a change in cut quality or
performance is noticable. Inspect the blade every couple hours of use. Blade sharpening needs vary with local condi-
tions. A dull blade tears the grass instead of cutting it. Torn grass blades leaves a rough look and makes the grass
vulnerable to diseases.
Blades need to be examined for damage before sharpening. Blades must be balanced after sharpening to
reduce the vibrations felt from the deck.
Bent blades are a sign of a blade impact. The blades must be replaced and the engine inspected for a bent
crankshaft if a bent blade is found. A bent blade or a bent crankshaft will cause other damage to the mower. A typical
customer complaint would be that parts are vibrating and falling-off the mower. In extreme cases, when the mower is
run with a bent blade or crankshaft, the engine can tear loose from the deck.
Do not attempt to straighten a bent blade or crankshaft. The bent part must be replaced. In the case of the crank-
shaft, solutions include, replacing the crankshaft, replacing the short block, replacing the complete engine, or replac-
ing the mower.
Bent blades and bent crankshafts are seldom warrantable damage.
Blades come in a variety of styles; side discharge, mulching, bagging, combination, there are even de-thatching
blades on the market. The C and D Series mowers come equipped with a 3-in-1 blade from the factory. The outer
part of the leading edge cuts the grass. A wing on the back edge lifts the grass for the next blade and propels clip-
pings toward the bag or side discharge chute if the path to either is open. A stepped-up cutting edge just in-board of
the outer cutting edge mulches clippings as they fall, if the side and/or rear discharge chute(s) are closed and the
mulch plug is in place.
The air flow in the cutting deck is generated by the spinning blade. If the blade is mounted upside down, the air
flow will be reversed pushing the grass down instead of standing up.
NOTE: Blades that are mounted upside down increase the risk of impact damage.
Running a mower with a bent blade will cause damage to the mower and can create a thrown
object hazard. As soon as damage or vibration is noted, the mower should be taken out of ser-
vice until the problem is repaired.
! CAUTION! CAUTION
Straightening a bent blade or crankshaft increases the damage to the metal. This can create a
thrown object hazard.
! CAUTION! CAUTION
An incorrect or improperly mounted blade can create a thrown object hazard.
! CAUTION! CAUTION
CHAPTER 2: BLADE AND BELT

C and D series mowers
8
Blade Removal
To remove the cutting blade:
1. Make the mower safe to tip-up.
1a. Allow the engine to cool if it has been run
recently.
1b. Drain the fuel tank to a level that will prevent
spillage.
1c. Disconnect and ground the spark plug wire.
2. Tip the mower with the muffler side down, or tilt the
mower back on a lift or workbench. Secure the
mower safely so that it will not fall. See Figure 2.1.
3. Block the blade from rotating using a block of wood
or a blade holder tool.
NOTE: MTD blade holding tool, part number 490-
850-0005, can be used block the blade.
See Figure 2.2.
4. Remove the blade bolt and diamond-shaped
Belleville blade spring using a 5/8” wrench.
! WARNING! WARNING Before tipping the mower to work on it, make sure it will not start unexpectedly, spill
fuel, or create a burn hazard. The engine should be cool, the fuel tank should be
empty or nearly empty, and the ignition system should be fully disabled.
Figure 2.1
Mower secured in vertical
position on a lift provides
easy access under the deck.
Figure 2.2
Blade holding tool
Blade bolt
Use care around the blade while
removing or tightening the bolt. The
blade can spin and cause injury.
! CAUTION! CAUTION

Blade and Belt
9
5. Lift away the blade.
6. Inspect the blade. If it is bent or worn beyond proper
sharpening, replace it with a new blade.
7. Sharpen and balance the blade if it is not badly worn.
NOTE: If the customer complains of vibration or parts fall-
ing off, or if the mower is showing signs of vibration
fatigue damage, there is reason to suspect a bent
blade and/or bent crankshaft.
8. Check the blade adapter, crankshaft and hardware for damage: See Figure 2.3.
• The end of the crankshaft should not wobble or orbit when the crankshaft is rotated.
• The key in the blade adaptor and the keyway in the crankshaft should engage firmly. The blade adaptor
should not spin on the crankshaft.
• The bowtie-shaped boss and embossed pins on the blade adaptor should not be deformed. Correspond-
ing holes in the blade should match the blade adaptor and fit securely over the bosses (drive features) on
the blade adaptor.
• The blade bolt should not be damaged, and the bellville spring that fits between the bolt head and the
blade should still have tension.
9. Install the blade with the blade adapter and Belleville
spring washer properly positioned: See Figure 2.4.
• The part number and the word “BOTTOM” should
face the ground when the mower is in its normal
operating position.
• The wings at the ends of the blade should point up,
into the deck shell.
• The lips on the center span of the blade should curve
down, away from the blade adaptor
NOTE: Aftermarket blades in non MTD brands or Arnold
brand may not have the correct shape drive fea-
ture, and may not meet safety requirements for
thrown objects.
10. Tighten the blade bolt to a torque of 450-600 in.-lb.
(50-70 Nm).
11. Put the mower back in its normal operating position, and insure that it is safe to operate.
12. Test-run the mower in a safe place. Do not put an unsafe mower back into service.
Figure 2.3
Blade adaptor
Blade
Bellville spring
Blade bolt
Bowtie feature
Drive pins
Figure 2.4
450-600in.-lb.

C and D series mowers
10
Blade Sharpening
1. Determine if the blade is too worn to sharpen:
• The minimum width of the blade at its narrow-
est point should be no less than 1-5/8”
(4.1275cm).
• There should be no bending, metal separation,
or obvious physical damage.
• The wings should still have a square trailing
edge that is 50% of the thickness of the original
blank (blade stock).
• There should be no damage to the drive fea-
ture.
2. To sharpen the cutting blades: See Figure 2.5.
• Dress the original bevel of the cutting edge.
• Do not sharpen the bottom edge of the blade,
and do not extend the bevel beyond the length
of the original cutting edge.
• Remove equal amounts of metal from both ends
of the blade, maintaining the original 29° to 32°
angle.
3. Balance the blade after sharpening: dress the edge of
whichever end of the blade is heavier until the blade
stays level on the balancer. See Figure 2.6.
NOTE: MTD blade balancer AR-SBB-102 or the
blade balancing kit, AR-BSK-1 can be used to
balance the blade.
Use proper safety equipment when sharpening blades: wear eye protection and keep all
guards in place on the grinder used for sharpening.
! CAUTION! CAUTION
Figure 2.5
Blade sharpening
on a bench grinder
Figure 2.6
Blade balancing:
NOTE: the blade is positioned upside-
down for better fit on the balancer
A poorly balanced blade will cause
excessive vibration and may cause
damage to the mower and result in
personal injury.
! CAUTION! CAUTION

Blade and Belt
11
Belt Removal
The traction drive clutch and ground speed are controlled by two cables on the C & D series mowers. The clutch
cable tilts the transmission back, tightening the drive belt. When the belt is tightened, it drives the input pulley on the
transmission. The second cable moves a cam that closes the sheaves of the pulley, changing the effective circumfer-
ence of the pulley, and changing the drive ratio.
NOTE: Use only the correct OEM part number belt.
• A belt that is too long may not engage fully and may not provide the full range of speeds, losing top speed.
• A belt that is too short may not disengage fully, and may drive the transmission even when the clutch lever
is released.
• A belt that does not have the same profile or wrapping may not perform as intended.
• The belts used on the C & D series mowers come from various belt manufacturers, but are made to MTD
specifications. These specifications are tailored to the mower design, and seldom work-out to standard
belt lengths. If MTD went to the trouble and expense of designing a belt for the application, there is a rea-
son they did so.
NOTE: If the belt has broken prematurely, identify and correct the cause of the failure before returning the
mower to service.
1. Confirm that the mower is set to its lowest ground
speed position, indicated by a 1 at the speed control
on the handlebar.
2. Remove the blade by following the steps described in
the blade section of this chapter.
3. Rotate the crankshaft to align the blade adaptor to
the opening in the lower belt cover.
4. Remove the two shoulder screws that hold the lower
belt cover to the deck. See Figure 2.7.
5. Remove the lower belt cover.
Figure 2.7
Lower belt cover
Shoulder screws

C and D series mowers
12
6. Slide the blade adaptor / drive pulley off of the
crankshaft. The belt will come off with it.
See Figure 2.8.
7. At the back of the mower, lift the rear grass door to
reveal the upper belt cover. Secure the grass door
with a prop or a strap.
8. Remove the screw that secures the upper belt
cover. Tilt the back of the cover up, and draw the
cover back to release the tabs that locate the front
edge of the cover.
9. Lift the transmission cover off of the mower.
See Figure 2.9.
10. Unhook the loop in the drive clutch cable from the
post that the upper belt cover screw goes into.
11. Unhook the clutch release spring from the brackets
that hold it, and remove it from the mower.
See Figure 2.10.
Figure 2.8
Belt
Blade adaptor
Figure 2.9
Transmission
cover
Figure 2.10
Drive clutch cable
Clutch
release spring

Blade and Belt
13
NOTE: It is not strictly necessary to disconnect the cables,
but doing so will make alignment and installation of
the belt keeper / bracket easier during reassembly.
12. Squeeze the barb on the bottom end of the drive
clutch cable to release it from its bracket.
See Figure 2.11.
13. Pry the curved end of the speed control cable hous-
ing out of its bracket, and unhook the Z-fitting from
the arm on the speed control cam. See Figure 2.12.
14. Remove the two screws that hold the combination
belt keeper / cable bracket to the transmission using
a 1/4” wrench. See Figure 2.13.
NOTE: There is a locating post on the side of the bracket
that is opposite the two screws.
Figure 2.11
Bracket
Barb
Figure 2.12
Speed control cable
Figure 2.13
Locating post
Mounting screws

C and D series mowers
14
15. Work the belt off of the transmission pulley and
remove it from the mower. See Figure 2.14.
16. Check the belt, pulleys, and cables for any problems
that might cause premature belt failure:
• Work the drive clutch control and check the
cable for full travel and smooth operation.
• Work the speed control, and check the cable for
full travel and smooth operation.
• Check the pulley sheaves for signs of belt slip-
page like polished contact surfaces or belt
debris / dust.
• Look for signs that foreign objects may have
damaged the belt.
17. Work the speed control cam through its full range of
travel to confirm that it move freely. See Figure 2.15.
18. Repair any problems that will damage the new belt.
Belt Replacement
1. Put the new belt onto the transmission pulley,
extending the belt toward the crankshaft.
2. Slip the belt into the pulley on the blade adaptor,
then slide the blade adaptor onto the crankshaft.
See Figure 2.16.
3. Install the blade adaptor/pulley onto the crankshaft.
Figure 2.14
Figure 2.15
Sheaves spread:
high speed
Sheaves together:
low speed
Figure 2.16

Blade and Belt
15
4. Position and attach the belt keeper / bracket to the
transmission. See Figure 2.17.
• The left leg of the bracket locates over a post on the
transmission housing.
• The right leg of the bracket is secured with two
screws that go into the plastic transmission housing.
• Do not over tighten the screws.
5. Reinstall the clutch control cable, the ground speed
control cable, and the clutch release spring.
See Figure 2.18.
6. Rock the transmission back, or squeeze the clutch
lever to tighten the belt.
7.Install the lower belt cover, being careful to route the belt
inside of all four metal belt guide pins that are molded into
the cover. See Figure 2.19.
Figure 2.17
Left leg
Locating post
Right leg
Figure 2.18
Cables and spring
reinstalled
Figure 2.19
Belt guide pins
Figure 2.20
Belt guide pins
Lower belt cover

C and D series mowers
16
8. Install the blade, and tighten the blade bolt to a torque of 450-600 in.-lb. (50-70 N-m)
9. Check the operation of the new belt:
See Figure 2.21.
9a. With the spark plug still disconnected, support
the rear of the mower so that the wheels are
off the ground, while the front wheels rest on
the ground.
9b. Operate the drive clutch to confirm that the
transmission rocks back to engage the drive
belt, then rocks forward to de-clutch the drive
belt when the clutch control is released.
9c. Use your left hand to hold the safety bail and
drive clutch lever. Pull the recoil rope with
your right hand, and move the speed control
lever through its full range of travel using your
left thumb. The speed cam should open and
close the sheave on the transmission pulley
in response to the speed control input.
NOTE: The sheave will open when the transmission pulley is stationary, moving from a speed drive ratio to a
power drive ratio (from 1 to 4 on the speed selector). The belt and transmission pulley must be rotating
for the sheave to close without placing undue stress on the speed control cam.
10. Install the transmission cover and test run the
mower in a safe area. See Figure 2.22.
10a. Test all operational and safety features before
returning the mower to service.
10b. Adjust the thumb roller on the bottom side of
the speed control assembly to set the correct
belt tension.
• Rolling the adjuster toward the front of the
mower will increase belt tension. There is an
embossed arrow pointing in this direction, adja-
cent to the roller.
• Rolling the adjuster toward the rear of the
mower will decrease belt tension.
•Too Tight: If the speed control lever jumps
from Speed #4 to Speed #3, or from Speed #3
to Speed #2, when the drive clutch lever is
engaged with the engine running, the belt tension is too high.
•Too Tight: If the mower wants to “creep” when the speed control lever is in Speed #4 and the drive clutch
lever is not squeezed, the belt tension is too tight. If rolling the adjuster toward the rear of the mower does
not stop the creeping, further investigation is required.
•Too Loose: If the mower does not have sufficient drive force to spin its wheels on smooth concrete (not a
broomed or florette surface) with the drive clutch engaged, and the speed control lever set for Speed #1,
the belt tension is too low, and the adjuster should be rolled toward the front of the mower to tighten the
belt.
Figure 2.21
Figure 2.22