Governor; Governor Arm - MTD P90 series Shop Manual

P90 Series Vertical Shaft Engines

Governor

The engine speed is controlled by a balance
between the force applied by a spring (pulling the throttle
open) and a flyweight mechanism within the engine apply-
ing force to the governor arm (pushing the throttle closed).
See Figure 4.23.
NOTE: While the mechanism is simple and robust,
it is important to pay attention when working
on parts near the governor. Binding caused
by interference with mis-routed lines or
cables may make the governor unrespon-
sive.
NOTE: When a governed engine "hunts", it is gen-
erally an indication of a lean fuel/air mixture,
rather than a problem with the governor.

Governor arm

To remove the governor arm from the governor shaft:
1. Remove the two screws, indicated by the arrows in
Figure 4.24., that hold the governor guard in place
using a 8 mm wrench.
2. Lift the guard up and hold it out of the way.
NOTE: The fuel line is attached to the guard with
two barbed eyelets. It is not necessary to
disconnect the fuel line from the guard, but
doing so will make it easier to access the
governor arm.
3. Remove the throttle cable clamp.
4. Disconnect the throttle cable.
5. Remove the upper screw that holds the control
panel to the engine block. See Figure 4.25.
6. Loosen the lower screw that holds the control panel
to the engine block.
7. Swing the control panel towards the front of the
engine.
46
Throttle linkage
Governor spring
Figure 4.23
Figure 4.24
Figure 4.25
Spring tension
Governor action
upper screw