VARIABLE SPEED MECHANICAL GOVERNOR
The variable speed mechanical governor performs three
A fuel rod connected to the differential lever and injector
control tube lever, provides a means for the governor to
change the fuel settings of the injector control racks.
1. Controls the engine idle speed.
The engine idle speed is determined by the centrifugal
2. Limits the maximum no-load speed.
force required to balance out the tension on the variable
speed spring in the low speed range.
3. Holds the engine at any constant speed, between idle
and maximum, as desired by the operator.
Adjustment of the engine idle speed is accomplished by
changing the tension on the variable speed spring by
The single weight governor is mounted on the front of
means of the idle speed adjusting screw. Refer to Page
the blower and is driven by the upper blower rotor (Fig.
Adjustment of the maximum no-load speed is
The governor consists of four subassemblies:
accomplished by varying the tension on the variable
speed spring by the installation or removal of stops and
1. Control Housing Cover.
shims, as required.
maximum no-load speed adjustment.
2. Control Housing.
3. Weight and Housing.
Surplus oil returning from the cylinder head provides
lubrication for the parts in the governor control housing,
4. Variable Speed Spring Housing and Shaft.
the riser thrust bearings, and the weight shaft end
bearing. Oil, picked up from a reservoir in the blower
front end plate, by a slinger attached to the lower rotor
shaft, provides lubrication for the governor weights and
Two manual controls are provided on the variable speed
governor: a stop lever for starting and stopping, and a
speed control lever (Fig. 1). For starting, the stop lever
Pressure lubrication has been provided for the weight
is moved to the run position, which holds the injector
control racks near the full-fuel position.
housing bearings on current engines. The oil tube is
attached between the oil gallery in the cylinder block
Upon starting, the governor moves the injector racks
and the governor weight housing.
toward the idle speed position. The engine speed is
then controlled manually by moving the speed control
The centrifugal force of the revolving governor weights
Governor operation should be checked as outlined on
is converted into linear motion, which is transmitted
through the riser and operating shaft to the operating
engine. If, after performing these checks, the governor
shaft lever. One end of the operating lever bears
fails to control the engine properly, it should be removed
against the variable speed spring plunger, while the
other end provides a changing fulcrum on which the
differential lever pivots.
1. Refer to Fig. 2 and disconnect the throttle control
rod and booster spring from the speed control lever.
The centrifugal force of the governor weights is opposed
by the variable speed spring.
Load changes or
2. Remove the four cover screws and lift the governor
movement of the speed control lever momentarily
cover, with the stop lever and retraction spring and
creates an unbalanced force between the revolving
cover gasket from the governor housing.
governor weights and tension on the variable speed
spring. When the forces reach a balanced condition
3. Refer to Figs. 1 and 2 and disconnect the fuel rod
again, the engine speed will be stabilized for the new
from the differential lever and injector control tube lever.
speed setting or new load.