ENGINE PROTECTIVE SYSTEMS
MANUAL SHUT-DOWN SYSTEM
The manually operated emergency engine shut-down device, mounted in the air inlet housing, is used to stop the engine
in the event an abnormal condition should arise. If the engine continues to run after the engine throttle is placed in the
no-fuel position, or if combustible liquids or gases are accidentally introduced into the combustion chamber causing over-
speeding of the engine, the shut-down device will prevent damage to the engine by cutting off the air supply and thus
stopping the engine.
The shut-down device consists of an air shut-off valve mounted in the air inlet housing which is retained in the open
position by a latch. A cable assembly is used to remotely trip the latch. Pulling the emergency shut- down knob all the
way out will stop the engine. After the engine stops, the emergency shut-down knob must be pushed all the way in and
the air shut-off valve manually reset before the engine can be started again.
AUTOMATIC MECHANICAL SHUT-DOWN SYSTEM
The automatic mechanical shut-down system illustrated in Figure 2 is designed to stop the engine if there is a loss of oil
pressure, loss of engine coolant, overheating of the engine coolant, or overspeeding of the engine. Engine oil pressure is
utilized to activate the components of the system.
A coolant temperature-sensing valve and an adaptor and copper plug assembly are mounted on the exhaust manifold
outlet. The power element of the temperature-sensing valve is placed against one end of the copper plug, and the other
end of the plug extends into the exhaust manifold. Engine coolant is directed through the adaptor and passes over the
power element of the valve. Engine oil, under pressure, is directed through a restricted fitting to the temperature-
sensing valve and to an oil pressure actuated bellows located on the air inlet housing.
Figure 2. Mechanical Shut-Down System Schematically Illustrated