TM 5-3810-300-24&P-3
2.7
MECHANICAL GOVERNORS
firing properly, remove the injector, test it and, if necessary,
Horsepower requirements on an engine may vary due to
recondition it as outlined in Section 2.1 or 2.1.1.
fluctuating loads; therefore, some method must be provided to
control the amount of fuel required to hold the engine speed
3. Check for bind that may exist in the governor operating
reasonably constant during load fluctuations. To accomplish
mechanism or in the linkage between the governor and the
this control, a governor is introduced in the linkage between
injector control tube.
the throttle control and the fuel injectors. The governor is
mounted on the front end of the blower and is driven by the
With the fuel rod connected to the injector control tube lever,
upper blower rotor.
The following types of mechanical
the mechanism should be free from bind throughout the entire
governors ate used:
travel of the injector racks. If friction exists in the mechanism,
it may be located and corrected as follows:
1. Limiting Speed Mechanical Governor.
(Grove Crane
Application)
1. If an injector rack sticks or moves too hard, it may be due to
the injector hold-down clamp being too tight or improperly
2. Variable Speed Mechanical Governor.
positioned. To correct this condition, loosen the injector
clamp, reposition it and tighten the clamp bolt to 20-25 lb-ft
Engines requiring a minimum and maximum speed control,
together with manually controlled intermediate speeds, are
equipped with a limiting speed mechanical governor.
2. An injector which is not functioning properly may have a
defective plunger and bushing or a bent injector rack.
Engines subjected to varying load conditions that require an
Recondition a faulty injector as outlined in Section 2.1 or 2.1.1.
automatic fuel compensation to maintain a near constant
engine speed, which may be changed manually by the driver,
3. An injector rack may bind as the result of an improperly
are equipped with a variable speed mechanical governor.
positioned rack control lever. Loosen the rack control lever
adjusting screws. If this relieves the bind, relocate the lever on
Each type of governor has an identification plate located on
the control tube and position the rack as outlined in Section
the control housing, containing the governor assembly
number, type, idle speed range and drive ratio. The maximum
engine speed, not shown on the identification plate, is
4. The injector control tube may bind in its support brackets,
stamped on the option plate attached to the valve rocker
thus preventing free movement of the injector racks to their no-
cover.
fuel position due to tension of the return spring. This condition
may be corrected by loosening and realigning the control tube
Check Governor Operation
supporting brackets. If the control tube support brackets were
loosened, realigned and tightened, the injector racks must be
Governor difficulties are usually indicated by speed variations
repositioned as outlined in Section 14.
of the engine; however, it does not necessarily mean that all
such speed fluctuations are caused by the governor.
5. A bent injector control tube return spring may cause friction
Therefore, when improper speed variations are present, check
in the operation of the injector control tube. If the spring has
the engine as follows:
been bent or otherwise distorted, install a new spring.
1. Make sure the speed changes are not the result of
6. Check for bind at the pin which connects the fuel rod to the
excessive load fluctuations.
injector control tube lever; replace the pin, if necessary.
2. Check the engine to be sure that all of the cylinders are
If, after making these checks, the governor fails to control the
firing properly (refer to Section 15.2). If any cylinder is not
engine properly, remove and recondition the governor.
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