Observe nozzle tip for fuel leakage. If
nozzle does not leak, the nozzle valve is seating
properly in the valve body. If drops of fuel collect at
a pressure of approximately 200 psi, or less, below
popping pressure, the nozzle valve is not seating
properly. In this case, the valve body and valve
must be removed for cleaning and inspection.
d. If the nozzle proved satisfactory when subjected
to the leakage test above, operate handle at a speed
of approximately 100 strokes per minute and observe
nozzle spray pattern.
e. The nozzle tip has four equally spaced holes,
90 degrees apart.
Size and spacing of these holes
determine the spray pattern. If fuel is discharged
evenly through all four holes at specified popping
pressure, the spray pattern is considered satisfact-
ory. However, if fuel is not discharged evenly
from all four holes, a plugged hole(s) is indicated,
in which case, the nozzle must be removed and
cleaned using a proper size cleaning wire.
f. Install nozzle holder cap nut and tighten it to
60 to 75 foot-pounds torque.
14-41. Nozzle Holder Assembly Installation.
Install the nozzle holder assembly. Refer to opera.
tor and Organizational Maintenance Manual.
Section VIII. FUEL INJECTION PUMP AND RELATED PARTS
a. The fuel injection pump is a single cylinder,
opposed plunger, inlet metering, distributor type.
The plungers are operated by an internal cam ring.
The purpose of the pump is to accurately deliver
metered quantities of fuel under high pressure to the
nozzle holder assemblies through which the fuel is
introduced into the engine combustion chambers, at
a definite timing in relation to the engine firing cycle,
and within the required injection period.
b. On Class 1, Precise Sets, the fuel injection
pump is controlled by the hydraulic actuator. The
hydraulic actuator operates on the shut down lever
to automatically control fuel flow through the fuel
injection pump, dependent upon load conditions, and
thus controls engine speed and response to load
c. On Class 2, Utility Sets, this fuel injection
pump is manually controlled from the control located
at the rear of the set. The manual control is con-
nected to the throttle through a cable and sleeve
d. The fuel injection pump also has an integral
back-up governor of the mechanical centrifugal
This governor is driven directly off
the pump drive shaft without gearing.
e. The transfer or supply pump, in the opposite
endof the rotor from the pumping cylinder, is a
positive displacement vane type enclosed by the end
plate. The pump is self-lubricated by the fuel
f. Fuel shut-off is accomplished electrically by a
solenoid mechanism within the fuel pump. When
energized, the solenoid opens the metering valve to
permit fuel flow to the engine.
g. An external adjustment knurled screw at the rear
of the pump housing provides precise control of gover-
nor sensitivity by decreasing or increasing the
effective length of the governor control spring.
Turning the adjustment screw inward shortens the
control spring, making it less sensitive and increasing
Turning the screw outward has the
Regulation of 2-3 percent can be
easily attained and adjustment can be made while the
engine is operating.
14-43. Fuel Injection Pump Removal and Disassembly.
Symptoms and Isolation of Malfunction. A
malfunction of the fuel injection pump is usually indi-
cated by loss of engine speed and power, erratic
engine speed, failure of engine to start (when electric
starter is working correctly), or sudden engine shut-
down when there is no fault indication such as low fuel,
high coolant temperature, or low oil pressure. To
isolate the malfunction to the fuel injection pump,
proceed as follows:
(1) Check fuel lines and fuel injection pump for
visible signs of leakage.
(2) If engine cannot be started or if it has shut
down suddenly, loosen the fuel input line to the fuel
If a full line of fuel is available, it
may be an indication that the pump has failed. Tighten
(3) While engine is cranking, loosen the input
to one of the fuel injectors. If there is no evidence of
available fuel, the fuel injector pump has failed.
(4) Remove timing cover on pump and observe
that pump rotates when engine cranks.
(5) Check for 24 Vdc at solenoid terminals on
top cover. of injection pump.
(6) Check solenoid (para 14-46). If no conti-
nuity, replace solenoid.
(7) Refer to table 14-1 for troubleshooting the
fuel injection pump.
b. Removal. (See figure 14-20.)
(1) Refer to the Operator and Organizational
Maintenance Manual and drain fuel day tank and dis-
connect fuel line to pump.