B
SPEED CONTROL
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
25
Repair and Service Manual
653045
SPEED CONTROL
Fig. 1 Accelerator and Speed Control System
NOTICE: The linkages that control the accelerator
mechanism, governor and carburetor are designed
to operate as an integrated assembly. Any adjust-
ment to one portion of the system will have an effect
on the other components within the system.
Hardware that is removed must be installed in its
original position unless otherwise specified. If the
torque values are not specified, refer to the Torque
Specifications table in the GENERAL INFORMA-
TION AND ROUTINE MAINTENANCE section.
To decrease the risk of possible
injury or death, follow the lifting
procedure in SAFETY section of
this manual. Place wheel chocks
in front and behind the rear wheels. Check the sta-
bility of the vehicle on the jack stands before start-
ing any repair procedure. Never work on a vehicle
that is supported by a jack alone.
SYSTEM OPERATION
Pedal Box Operation
When you press the accelerator, the accelerator rod
moves towards the rear of the vehicle by overcoming the
resistance of the accelerator return spring (Ref. Fig. 1).
As the accelerator pedal moves, the parking brake is
released, the micro switch closes and activates the igni-
tion circuit.
The rear end of the accelerator rod is joined to the micro
switch cam which connects to the accelerator cable.
As the micro switch cam moves to the rear it pulls the
accelerator cable, which pulls against the governor
spring.
When the accelerator cable pulls against the accelerator
cable/governor spring, the spring extends until it over-
comes the resistance exerted by the governor mecha-
nism. As the governor spring overcomes these forces, the
governor arm moves and the motion is transferred
through linkage rod to the carburetor throttle plate.
Governor Operation
Until the vehicle reaches its governed speed, the vehicle
will continue to accelerate in relation to the accelerator
pedal position.
When the governed speed is reached, the ground speed
governor in the rear axle assembly operates against the
accelerator cable/governor spring and closes the throttle
lever until the correct governed speed is achieved
(Ref. Fig. 1).
It is the force of the accelerator cable/governor compres-
sion spring in response to accelerator pedal and governor
lever (7) position which controls the position of the throttle
plate.
The compression spring provides cushioning of sudden
changes in throttle linkage position to provide smooth
Governor Lever - Upper
Governor Lever - Lower
Governor
Spring
Accelerator
Compression
Spring
Accelerator Cable
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