Troy-Bilt 1900678 - Manual (Page 31)

Photo 5-20: Unhook wheel drive return spring.
G. Insert the new blade drive belt through the front of
the mower and seat one end on the blade drive rear
pulley. Make sure that the belt fits inside the belt guard
that surrounds the rear and sides of the pulley.
H. Install the other end of the belt on the blade drive
front pulley, making sure that the belt fits inside the
belt guide next to the pulley.
I. Seat the belt on the blade drive idler pulley, making
sure that the belt fits inside the idler pulley belt guide.
Securely tighten the screw and nut on the idler pulley.
J. On self-propelled models only, reinstall the spring
in the main wheel engagement bracket, making sure
that the hook is engaged fully.
K. Adjust the tension on the belt by following Steps C
through J of the previous “Blade Drive Belt Tension”
instructions.
IMPORTANT
After replacing blade drive belt, perform the Blade Brake
Control Test Procedure described on Page 34 to ensure
that the Blade Brake Control System is operating properly.
WHEEL DRIVE CHAIN TENSION
(Self-Propelled Models Only)
Periodically check the tension on the wheel drive
chain. Due to normal stretch and wear on the chain, it
may need occasional tightening.
S CAUTION: To avoid personal injury, stop the
engine disconnect the spark plug wire, keep
the wire away from the spark plug, and allow the
engine and muffler to cool before inspecting or
servicing the drive chain.
TOOLS NEEDED: Two 7/16" Wrenches, Flat Blade
Screwdriver.
A. Remove the belt/pulley safety cover by removing
the three hex nuts and two self-tapping screws.
B. To check for correct tension, use your thumb to
press in on the center of the chain. See Photo 5-21.
The chain tension is correct if the chain deflects approx­
imately 1/8" to 1/4".
C. To adjust the tension, slightly loosen the two chain
drive adjustment screws on the right side of the friction
drive axle assembly. See Photo 5-22. Push the axle
assembly up to tighten the chain, or down to loosen
the chain, and retighten the two screws.
D. Loosen the two adjustment screws on the left side
of the axle assembly and adjust that end of the axle
assembly an equal distance up or down (the two front
screws must be in the same relative positions in their
adjustment slots). Tighten the two left side screws se­
curely.
E. Check the tension on the chain as previously ex­
plained in Step B. Repeat Steps C and D as necessary.
F. Replace the belt/pulley safety cover, fastening it
securely.
G. Check that the clearance between the wheel drive
rollers and the tires is correct. See “Adjusting Wheel
Drive Traction” on Page 22.
Photo 5-21: Check wheel drive chain tension.
Photo 5-22: Loosen screws to adjust chain tension.
REPLACING THE BLADE BRAKE BAND
A CAUTION: To avoid personal injury, stop the
ilA engine, disconnect the spark plug wire, keep
the wire av/ay from the spark plug, and allow the
engine and muffler to cool before removing or
replacing the blade brake band.
TOOLS NEEDED: Pliers
A. Remove the belt/pulley safety cover by removing
the three hex nuts and two self-tapping screws.
B. Unhook the blade brake spring from the blade
drive engagement bracket. See Photo 5-23.
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