Troy-Bilt 643D-Tuffy/Bronco, 643B, 645A - Super Bronco manual Checking and Adjusting, Forward

WARNING: Before inspecting, cleaning or servicing the machine, shut off engine, wait for all moving parts to come to a complete stop, disconnect spark plug wire and move wire away from spark plug. Failure to follow these instructions can result in serious personal injury or property damage.

						b. Unthread the hex nut (C, Figure 5-4)
						halfway up the adjustment screw (D).
						c. Unhook the top of the spring from the
						Forward Clutch Bail.
						d. Use pliers to prevent the adjuster (B)
						from turning and turn the slotted screw lo-
						cated inside the spring clockwise (viewed
						from operator’s position) to increase ten-
					D	sion on the spring. Turn the screw counter-
						clockwise to decrease tension. Once
						adjusted, reattach the spring to the For-
	C					ward Clutch Bail.
						e. Repeat Steps 2 and 3 to re-measure the
						length of the spring. When the second mea-
						surement is between 1/16" -to- 3/16" longer
	A				B	than the first measurement, retighten the hex
						nut (C) against the top of the adjuster (B).
FORWARD
						Replacement Belt Information
						If the drive belt needs to be replaced, see
Figure 5-3: Install tines so that cutting edge of tines enter soil first when tiller moves forward.
						your local authorized dealer or refer to the
CHECKING AND ADJUSTING		tension is correct if this second measure-				Parts List for ordering information. Use
FORWARD DRIVE BELT TENSION		ment is between 1/6" -to- 3/16" longer than				only a factory-authorized belt as an “over-
						the-counter” belt may not perform satis-
It is important to maintain correct tension		the first measurement.
		4. If the spring is too short (less than				factorily. The procedure requires average
on the forward drive belt. A loose belt will						mechanical ability and commonly available
		1/16"), the tension is too loose. If the
cause the tines and wheels to slow down —						tools.
		spring is too long (more than 3/16"), the
or stop completely — even though the en-
		tension is too tight.
gine is running at full speed. A too tight
		5. To adjust the length of the spring:
belt can result in unintentional tine move-
ment when the clutch bail is in the Neutral		a. Release the Forward Clutch Bail.
(released) position.
						5
• Check belt tension after the first two
hours of break-in operation and after every						4
10 operating hours.					3
• At the end of each tilling season, check				A	2
the belt for cracks, cuts or frayed edges
			C
and replace it as soon as possible.					1
			B
To Check Forward Belt Tension:
					D
1. Stop engine, wait for all parts to stop
moving and disconnect spark plug wire.				Hold bail against handlebar while
2. With the Forward Clutch Bail in an open
				taking second measurement of spring
(released) position, measure and note the
overall length of the cable spring (A, Figure
5-4) by measuring from the outermost coil
to the outermost coil.
			Figure 5-4: To check forward belt tension, take two measurements of the
3. Squeeze the Forward Clutch Bail against
			overall length of the coils in the spring — first with the clutch bail open,
the handlebar (see Figure 5-4) and re-			then with the clutch bail closed against the handlebar.
measure the length of the coils. The belt
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