ARMY TM 9-6115-673-13&P
AIR FORCE TO 35C2-3-512-1
1.19.
SPEED CONTROL SYSTEM.
1.19.1. Diesel engine speed is maintained by the speed control system (Figure 1-5) which includes the mechanical
governor, governor lever, RUN lever, and STOP lever. The system is designed to maintain engine speed under load at
a constant rate of between 3570 and 3630 rpm (no load speed of 3750 rpm).
1.19.2. The governor is the flyweight-type, with the weights mounted on a gear driven by the engine camshaft gear.
The force of the flyweights is transferred through a thrust sleeve and collar to the governor lever which is balanced
against the tension of the governor spring. The spring is stretched between the governor lever and the engine RUN
lever. When the engine speed drops below the governed speed, the resulting decrease in governor flyweight/camshaft
rotation places tension on the governor spring. The tension repositions the fuel injection pump rack and increases the
stroke of the plunger in the fuel injection pump allowing more fuel to flow to the pump delivery valve. The increase in
fuel flow causes the diesel engine to speed up. As the diesel engine recovers to the governed speed, the governor
flyweight/camshaft rotation stabilizes and the tension on the governor spring relaxes. This changes the position of the
fuel injection pump rack and shortens the stroke of the plunger allowing less fuel to flow to the fuel injectors maintaining
the engine speed at 3600.
1.19.3. The governor control mechanism features two operator controlled levers. The black diesel engine RUN lever
places tension on a spring attached to the governor lever. The tension places the governor lever in a position to allow
fuel flow to the fuel injector for diesel engine start up and to allow the diesel engine to continue running after startup.
The red diesel engine shutdown or STOP lever is operated by either depressing the red STOP lever or by the low oil
pressure shutdown system. When depressed, the lever trips the RUN lever releasing the tension on the governor
spring which places the governor lever in a no fuel or stop position. This action shuts off fuel flow to the fuel injector
stopping the combustion process and shutting down the diesel engine.
