VARIABLE SPEED GOVERNOR
VARIABLE SPEED MECHANICAL GOVERNOR
The variable speed open linkage governor (Fig.
1) performs the following functions:
1. Controls the engine idle speed.
2. Limits the maximum no-load speed.
3. Holds the engine at any constant speed,
between idle and maximum, as desired by the
The single-weight governor is mounted on the
rear end plate of the engine and is driven by a
gear that extends through the end plate and
meshes with either the camshaft gear or the
balance shaft gear, depending upon the engine
Two manual controls are provided on the
governor: a stop lever and a speed control
lever. In its normal position, the stop lever
holds the fuel injector racks near the full-fuel
When the engine is started, the
governor moves the injector racks toward the
Figure 1. Variable Speed Open Linkage
idle speed position. The engine speed is then
Governor Mounted on Engine
controlled manually by moving the speed
The centrifugal force of the revolving governor weights is converted into linear motion which is transmitted
through the riser and the operating shaft to the operating shaft lever. Movement of this lever is transmitted to
the stop lever which changes the fuel setting of the injector racks, since the fuel rod is connected between the
stop lever and the injector control tube.
The centrifugal force of the governor weights is opposed by the variable speed spring which is fastened to the
end of the operating shaft lever. Load changes or movement of the speed control lever momentarily creates
an unbalanced force between the revolving weights and the tension on the spring. When the forces reach a
balanced condition again, the engine speed will be stabilized for the new speed setting or new load.
To stop the engine, the speed control lever is moved to the idle-speed position and the stop lever is moved to
the no-fuel position and held there until the engine stops.
Adjustment of the governor is covered in Governor and Injection Rack Control Adjustment.