5 0 hours of operation. If the pintle
64. Fuel Injector Assemblies Reassembly,
opens above 1,850 or below 1,750 psi,
Testing, and Installation
adjust the spring pressure. Remove
the adjustment screw cover, and
assemble the fuel injector assembly in the re-
loosen the jamnut. Turn the adjusting
screw clockwise to raise the opening
Note. The capnut should be tightened to a torque of
pressure, and counterclockwise to
60 to 65 foot-pounds.
lower the opening pressure. Then
tighten the jamnut. Make several
tests, and set the pressure as precisely
( 1 ) Before installing on the engine, use a
a s possible. I n s t a l l t h e a d j u s t i n g
nozzle testing pump to test each fuel
injector assembly for leakage and
(4) After adjusting the opening pressure,
o p e n i n g pressure.
check the spray characteristic's while
( 2 ) Connect the fuel injector assembly on
working the pump at above 100
t h e end of the fuel line or fuel inlet
strokes per minute. The spray must
connection of the testing pump.
be uniform and of regular pattern,
Warning: When testing the fuel
w i t h o u t side streams or deflected di-
injector, keep hands away from the
rection. A faulty spray is caused by a
nozzle spray. The high velocity of the
dirty or defective nozzle valve.
fuel oil may puncture the skin and
Test for slow leakage by maintaining
cause blood poisoning.
t h e pressure below 1,750 psi. If there
(3) P u m p t h e n o z z l e t e s t e r l e v e r w i t h
is no discernible leakage when the
quick strokes for shock test of the
pressure is held within 1,650 to 1,900
nozzle. Open the gage valve and pump
psi on the gage, the nozzle is tight.
with steady even strokes until the
( 6 ) If the injector assembly passes these
g a g e indicates a pressure of 1,750 to
tests, it can be installed in the engine.
1,850 psi. The pintle should pop open
If the injector assembly does not pass
if the opening pressure is correct.
these tests, disassemble for cleaning,
When a new spring has been installed
r e i n s p e c t i o n , and replacement where
in an overhauled injector assembly,
s e t the opening pressure 10 percent
above normal to allow for spring set-
c . Installation. Install the fuel injector as-
ting which will occur within the first
semblies (TM 5-3820-20-20/1).
Se c t ion V I I I . FU EL I N J ECT I ON
PU M P AN D GOV ERN OR ASSEM BLY
taking place, the cause may be an injector not
a. The fuel injection pump and governor as-
z l e valve sticking open in the cylinder which
sembly used on this engine has a self-contained
i m m e d i a t e l y proceeds that cylinder in the en-
transfer pump which pumps fuel from the fuel
gine firing order. During injection to the cyl-
filters to the working parts of the injection
p u m p . The fuel injection pump and governor
inder which has the nozzle valve sticking open,
a s s e m b l y contains an electric solenoid that is
f u e l rushes into that cylinder with no restric-
a c t u a t e d by the electric governor. This sole-
t i o n , causing a scavenging effect in the pump
n o i d regulates the fuel flow and speed of the
d i s t r i b u t i o n rotor. This causes a partial loss in
fuel pressure to the following injector, the noz-
b . A characteristic of the Roosa-Master fuel
i n j e c t i o n pump is, that if engine misfiring is
in that cylinder.