TM-9-2350-261-34
CARRIER, M113A2, M577A2, M1064, M1068, M1059 AND M901A1
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL
TM-9-2350-261-34 - Page 30 of 785
TM 9-2350-261-34
THEORY OF OPERATION
0003 00
GENERAL INFORMATION: M113A2 FOV
The M113A2 FOV carrier is powered by a liquid cooled 6V53, 210 horsepower diesel engine. The engine power is converted
to mechanical power and transferred to the carrier tracks and other components through a transfer gearcase, transmission,
differential, and final drives.
The engine, transmission, and steering/braking system are driver controlled. Engine startup and shutdown are controlled by
electrical signals and mechanical linkages connected to the accelerator pedal, the fuel shutoff cable, and the hand throttle
cable. Steering/braking are controlled through linkages connected to the differential.
ENGINE AND DRIVE TRAIN
The engine converts air and diesel fuel into energy. The engine delivers this power to the transmission. A drive train transfers
power from the engine to the carrier tracks. The drive train consists of the engine, transfer gearcase, transmission, differential,
drive lines, final drive assemblies, and drive sprockets.
COOLING SYSTEM
The engine and transmission generate heat during normal operation. The cooling system transfers some of the heat to the
outside to maintain a safe operating temperature. The vent fan draws air in through the radiator, circulates it around the power
plant, and expels it through the exhaust grille above the vent fan. The vent fan is belt-driven from the engine crankshaft. A
mixture of antifreeze and water is pumped through the cooling system to cool the engine and transmission. The engine
cooling system has a capacity of 9.5 gallons (35.96 liters). The cooling system should be checked regularly. The auxiliary
radiator tank, located on the transverse beam, provides space for the separation of air and liquid coolant. Stop engine if
temperature goes above 200F(93
.3 C). Refer to Check/Fill Cooling System (TM 9-2350-261-10).
COLD START SYSTEM
The engine is equipped with a cold start system (air box heater). The air box heater heats the air entering the cylinders to
assist in ignition of fuel at low ambient temperatures (below 40F(4.4 C)). A fuel and air mixture is sprayed into the air box
and a spark ignites a flame. The flame heats the engine air, which is fed directly into the cylinders to make starting easier.
DIFFERENTIAL STEERING LEVERS
The differential steering levers are used to steer as well as stop the carrier. Pulling on one or both of the differential steering
levers applies the brakes in the differential steering unit. To turnleft
,graduallypullontheleftsteeringlever
.Toturnright,
gradually pull on the right steering lever. To slow or stop the carrier, gradually pull both steering levers. To lock the steering
levers in place, push down on the brake lock buttons, located on top of the steering levers. To release the steering levers
brake-lock buttons, pull back on the steering levers and the buttons will pop up.
PIVOT STEER LEVERS
The pivot steer levers are used to steer the carrier while in water and to turn a stopped carrier into a tight turn. To pivot steer
the carrier, bring the carrier to a stop and pull on the pivot steer lever. Pulling the pivot lever applies the disc brake, which
will lock up the one track and allow all of the differential power to be applied to the other back.
FUEL CUTOFF CONTROL
To start fuel flowing to the engine, push the fuel cutoff control all the way in. To stop fuel flow to the engine, pull the fuel
cutoff control all the way out. This will shut down the engine when it is running.
HAND THROTTLE CONTROL
Thehandthrottlecontrolisusedtosetthe engine speed for various reasons. To set the engine speed, while pushing down the
accelerator pedal, pull hand throttle control out until desired RPM is indicated by tachometer. Turn the hand throttle control
clockwise to lock the control and counterclockwise to release the control. Once the hand throttle control is set, the engine will
maintain the set speed without holding down the accelerator pedal.
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