Troy-Bilt 644HMBRONCO, 645AMBRONCO WARNING

Section5: Maintenance

WARNING Beforeinspecting, cleaningor servicing the unit, shutoff engine,wait for all

partsto cometoa completestop, disconnectsparkplugwire andmove wire away from spark

plug. Failure to follow these instructions canresult in serious personal injury or

propertydamage.

from turning by gripping the upper end of

thethreaded adjuster (B)with pliers.

6. RepeatStep 3 to measurethe length

ofthe clutch bail spring. Oncethe length

is correct, retighten the hex nutagainst

thetop of the adjuster.

ForwardBeltReplacementInformation

Ifthe drive belt needsto bereplaced, see

your local authorized dealer or phone the

factory as instructed on Page 2. Refer to

the PartsList in the back ofthis manual

for correct components Useonly OEM

(OriginalEquipment Manufacturer) fre-

placementbelts. A substitute belt may

notperform satisfactorily. Theprocedure

requiresaverage mechanicalability and

commonly availabletools.

FORWARDCLUTCH

BAILADJUSTMENT

Ifthe ForwardClutch Bail does not

function properly, first checkthat the

forward drive beltis adjusted properly

(see"Checking and Adjusting Forward

DriveBelt Tension"). If this failsto

correctthe problem, contact the factory

technicalservice departmentor your

authorizeddealer for serviceadvice.

CHECKINGANDADJUSTING

REVERSEDRIVEBELTTENSION

Maintainingcorrect tension onthe

reversedrive belt is important to good

performanceand long belt life. Aloose

beltwill slip on the engine and transmis-

sion pulleys and causethe tinesand

wheelsto slow down - or stop com-

pletely- eventhough theengine is

running atfull speed. Aloose belt can

also result in prematurebelt wear.

Ifthere is no reverseaction when the

ReverseClutchControl knob is pulled

out,then the belttension istoo loose.

Whenchecking belt tension, also check

the belt for cracks,cuts or frayed edges

and replaceit as soon as possible.

*Checkbelttension afterthe first two

hoursof break-inoperation (new belt).

- Check belttension afterevery 10

operatinghours.

ToCheckReverse BeltTension:

1. Besure that the engine is stoppedand

thespark plugwire is disconnectedand

movedaway from the sparkplug.

2. Removethe screw in the plastic belt

coverand slide the cover (which is

attachedto the forward clutch cable) out

ofthe way.

3. Haveanassistant pull the Reverse

ClutchControl knob all the way out and

hold it in that position. Measure the

lengthof the cable wire between the end

ofthe threaded cable adjuster (A, Figure

5-5) andthe end of the Z-fitting (B)to

whichthe cable wire is attached.

4.The belttension is idealif the cable

wire length measuresbetween1/8" to

1/4". Ifthe lengthis less than 1/8" (and if

there is no reverseaction when the tiller

is running), then makethe following

adjustments.NOTE:If the lengthis more

than 1/4", no adjustment isneeded,as

longas the reverseaction functions

properly.

5. Releasethe ReverseClutch Control

knob. Unthreadthe innerjam nut (C,

Figure5-6) oneto two turnsand pull the

threadedcable adjuster (A, Figure 5-6) to

the left untilthe inner jamnut rests

againstthe bracket.

6. Preventthe inner jam nut(C) from

turning and tighten the outer jam nut (D)

againstthe bracket. Preventthe outer

jam nut (D) fromturning andtighten the

innerjam nut (C)against the bracket.

7. Measurethe gapby repeating Step 3.

Readjustas neededby repeating Steps5

and6.

8. Reinstallthe belt cover.

Figure5-5: Measurecable wirelengthto

checkfor correctreverse belt tension.

Figure5-6: Movethreaded

adjuster(,4) to left to

increasebelt tension.

ReverseBeltReplacement Information