ARMY TM 9-6115-642-24
AIR FORCE TO 35C2-3-455-12
MARINE CORPS TM 09247A/09248A-24/2
1-12.2 Fuel System.
1-12.2.1 The Fuel System (FIGURE 1-3) includes a primary subsystem and an auxiliary subsystem.
1-12.2.2 The primary subsystem consists of fuel lines, fittings, fuel tank, Iow fuel Ievel float switch, fuel float switch mod-
ule, fuel level sender, FUEL LEVEL indicator, fuel transfer pump, fueL filter/water separator, fuel injection pumps, and four
injectors.
1-12.2.3 Injection pump output is controlled by a mechanical engine governor. The governor also includes a fuel solenoid —
operated shutoff lever which stops operation of the injection pumps when the solenoid is deenergized. With the MASTER
SWITCH in the START or either of the two RUN positions, both the fuel solenoid and the fuel transfer pump are energized.
The fuel solenoid positions the shutoff lever to the open position, and the transfer pump starts drawing fuel from the fuel
tank. After reaching the fuel transfer pump, fuel passes through a fuel filter/water separator where water and small impuri-
ties are removed. The fuel then goes to the injection pumps. With the engine cranking or running the fuel is metered, pres-
surized and pushed through the injectors by the injection pumps. Fuel is sprayed by the injectors into the engine combus-
tion chamber where it is mixed with air and ignited. The fuel that is not burned by the engine is returned to the fuel tank
by an excess fuel return line. Power is removed from the fuel solenoid and the transfer pump, stopping the engine whenev-
er the MASTER SWITCH is turned to OFF position. The fuel solenoid and transfer pump are also deenergized by the fault
system (refer to paragraph 1-12.1). The fuel level sender measures tank fuel level which is indicated by the FUEL LEVEL
indicator from E (empty) to F (full).
1-12.2.4 The auxiliary subsystem consists of an auxiliary fuel supply, fuel lines, fittings, auxiliary fuel filter, auxiliary fuel
pump, auxiliary fuel pump float switch located in the fuel tank, and a fuel float switch module.
1-12.2.5 When the MASTER SWITCH is set on PRIME & RUN AUX FUEL, it actuates the auxiliary fuel pump and trans-
fers fuel from the auxiliary fuel supply to the fuel tank The auxiliary fuel pump float switch shuts off the auxiliary fuel pump
when the fuel tank is full and reactivates the pump as the level drops. The fuel float switch module allows the current used
by the auxiliary fuel pump to bypass the float switch.
1-12.2.6 The 24 VDC control circuits provide control and power for operation of the fuel solenoid, indicators, fuel transfer
pump, and auxiliary fuel pump.
1-12.3 Generator Set Cooling Syste
Ii
m.
1-12.3.1 The Generator Set Cooling System (FIGURE 1-4) includes air intake and exhaust grilles, baffles, and ducting
within the generator set housing and the engine driven radiator cooling fan. The air intake grilles are located in panels on
both sides of the generator set housing. The air exhaust grille is located in the housing top panel.
1-12.3.2 Air is drawn in through the air intake grilles and forced through the engine coolant radiator and out of the genera-
tor set through the exhaust grille by the radiator cooling fan. Some of the air drawn into the housing is used by the Engine
Air Intake and Exhaust System (refer to paragraph 1-12.6). Most of the cooling air flows externally past the generator
assembly and engine. Some cooling air is circulated internally through the AC generator assembly by a generator fan
which is an integral part of the AC generator assembly. Baffles, ducting, and sound absorbing material are used to control
the air flow through the generator set and to reduce sound transmission through the grilles.
1-12.4 Engine Cooling System.
1-12.4.1 The Engine Cooling System (FIGURE 1-5) consists of a radiator, hoses, thermostat, temperature sender,
coolant high temperature switch, COOLANT TEMP. indicator, water pump, a belt driven fan, and cooling jackets (part of
engine).
1-12.4.2 The water pump forces coolant through passages (cooling jackets) in the engine blockandcylinderheadw here
the coolant absorbs heat from the engine. When the engine reaches normal operating temperature, the thermostat opens
and the heated coolant flows through the upper radiator hose assembly into the radiator. The cooling fan circulates air
through the radiator where the coolant temperature is reduced.
1-12.4.3 A coolant high temperature switch in conjunction with the fault system provides automatic shutdown in the
event that coolant temperature exceeds 225 ±5°F(107 ± 3°F). The COOLANT TEMP indicator indicates the engine cool-
ant temperature, from 120°F to240°F(48°Cto115°C).
1-10 Change 1
