TM 55-1930 209 14&P-91
Table C-1. Preventive Maintenance Checks and Services for Electrical Power Systems (Continued)
B - Before
D - During
A - After
H - Hourly Interval
Item to be
Check for and have repaired
or adjusted as necessary
Air must be vented from the fuel system
whenever any part of the system between
Fe fuel tank and Injection pump has been
disconnected for any reason or If the
system has been emptied of fuel.
(a) Unscrew by two or three turns, the vent
plug on top of the fuel filter cover (not
the return pipe to the tank). Later type
fuel filters are self venting and do not
have a vent plug. Air vent the fuel filter
by removing the excess fuel return
pipe. to the fuel tank, from the filter
head. Operate the fuel feed pump
priming lever until diesel fuel. free
from air bubbles, issues from the
nonreturn valve. Refit fuel return pipe.
(b) Loosen the vent screw on the hydraulic
head locking screw on the side of the
fuel injection pump body.
(c) Loosen the air vent screw on the side
of the governor control cover.
(d) Operate the priming lever of the fuel lift
pump. (H the cam on the engine
camshaft driving the fuel lift pump is on
maximum lift, it will not be possible to
operate the hand primer and the
engine should be turned one complete
revolution.) When diesel fuel, free from
air bubbles, Issues from each vent
point, tighten the connections in the
(1) Filter cover vent screw.
(2) Head locking screw vent valve.
(3) Governor cover vent valve.
(e) Loosen the pipe union nut at the pump
inlet Operate the priming device and
retighten when diesel fuel, free from air
bubbles, issues from around the pipe