Troy-Bilt 753B - Manual (Page 22)

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Section 5: Maintenance
BLADE BRAKE REPLACEMENT
Follow this procedure to install a new
blade brake.
To Remove Blade Brake:
1. Stop engine, wait for all parts to
stop moving, and disconnect spark
plug wire.
2. Remove belt cover as described in
“Belt Cover Removal” instructions.
3. Remove hardware (G, Figure 5-8)
securing blade brake (H).
4. Remove old brake (H) from idler
arm (I).
To Install Brake:
1. Position new brake (H) in place on
idler arm (I).
2. Center brake in sheave groove and
secure brake (H) with hardware (G) re-
moved earlier.
3. Reinstall belt cover securely.
4. Test operation of blade brake (see
“Blade Brake Control Test” in Operation
section).
BLADE DRIVE BELT
ADJUSTMENT
If the blade drive belt is slipping due to
lack of belt tension, follow the steps
below.
1. Stop engine, wait for all parts to
stop moving, and disconnect spark
plug wire.
2. Remove belt cover as described in
“Belt Cover Removal” instructions.
3. With mower on level ground, adjust
blade cutting height at about 3" (mea-
sure from ground to flat portion of
blade).
4. With the Blade Drive Control (Figure
5-7) in the disengaged position, set a
gap of 1/8" between the spring (F, Figure
5-9) and flat washer (E) by adjusting the
nut (D).
5. Reinstall the belt cover securely.
6. Test the operation of the blade brake
(see “Blade Brake Control Test” in the
Operation section).
7. If the drive belt slips during opera-
tion, it may be necessary to
relocate idler (J, Figure 5-9) in the slot
provided in the mounting bracket. With
the engine stopped and the spark plug
wire disconnected, loosen the hardware
on the idler (J) and slide it forward to
take up slack in the belt.
8. Engage the blade drive and measure
the distance (X, Figure 5-8) between the
centers of pulleys (K) and (L). The dis-
tance should be 5-1/2 to 5-5/8". After
obtaining the correct dimension, rein-
stall the belt cover securely and test the
operation of the blade brake.
BLADE DRIVE CONTROL LEVER
ADJUSTMENT
Make the following adjustment if the
Blade Drive Control Lever releases dur-
ing operation.
1. Stop engine, wait for all parts to
stop moving, and disconnect spark
plug wire.
2. Engage the Operator Presence
Control and the Blade Drive Control.
Without releasing the controls, look in-
side the cutout at the rear of the frame
and make sure the Operator Presence
Control latches (A and B, Fig. 5-10) are
fully engaged at point (C). If they are not
fully engaged, improper operation or
premature wear could result. To adjust,
loosen hex nut (D) and shorten length of
control rod (E). To avoid over-adjusting,
turn rod only 1 to 2 turns per adjust-
ment.
3. Tighten hex nut securely after adjust-
ing control rod.
4. Test by releasing the Operator
Presence Control. If properly adjusted,
the Blade Drive Control will disengage
when the Operator Presence Control is
released. Re-adjust as necessary by
repeating Steps 2 and 3.
Figure 5-9: Blade drive adjustment.
1/8"
J D
E
F
Adjust idler in direction
of arrow to tighten blade
drive belt
Figure 5-10: Blade Drive Control Lever
adjustment.
B
E
D
A
C
Before inspecting, cleaning or servicing the machine, shut off engine, wait for moving parts to stop, disconnect spark
plug wire and move wire away from spark plug. Remove ignition key (electric start models).
Failure to follow these instructions can result in serious personal injury or property damage.
WARNING