Service Manual

BBC Adjusting the Blade Brake (cont'd)
2. Remove the two screws securing the screen
panel to the top of the mower housing as shown
in Figure 22. Remove the panel.
3. Move the control bar down and lift up against the
handle. With the control bar against the handle,
measure the spring length
(L) at the front of the
spring
as shown in Figure 26.
Figure 26
4. If the spring dimension is greater than 32 mm
(1-1/4") an adjustment is needed.
5. To adjust, loosen the bottom jam nut on the blade
brake cable as shown
in Figure 27. Adjust the top
jam
nut until spring dimension is as near as
possible to
nut; not less than 25 mm (1”) See
note below.
NOTE: Adjusting the top jam nut too high can
cause the cable end to crush the plastic
fitting
when the control bar is moved up against the
handle.
If the spring cannot be adjusted to less
than
32 mm (1-1/4”) before the cable end
contacts the plastic fitting, the clutch belt is worn
out and should be replaced. After replacing the
belt, adjust the cable per the above procedure.
NOTE: 1990 and newer models are equipped
with finger
tip adjusters that do not require tools.
Use the same adjustment criteria on these
cables.
6. Tighten bottom jam nut to lock the adjustment.
Figure
27
BBC Check Control Bar Operation
The control bar should be checked periodically, at the
beginning of each mowing season
as a minimum, to
assure the Blade Brake Clutch (BBC) system is
operating properly.
1. Start the engine.
2. Push the control bar as shown to the lowest
position. See Figure
28. This 'latches' the
mechanism prior to engaging the blade.
3. Lift the control bar to the normal 'blade engaged'
position, about
50 mm (23 below the handle.
The 'fan' noise and bag inflation indicate that the
mower blade is engaged and rotating.
4. Release the control bar. A 'bang' should be
heard and the blade should stop within three
seconds. If the blade does not stop within three
seconds when the control
bar is released, refer
to BBC section for service information.
If your unit stops within the required three
seconds, the BBC system is operating properly.
However, to detect the BBC system deterioration
Maintenance
26 Vacu-Power Mower