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
Interval
Procedures:
Equipment Is
Item
Item to be
Check for and have repaired
Not Ready/
No.
B D
A
H
Inspected
or adjusted as necessary
Available If:
(c) With the valves rocking on No. 1
cylinder, set the valve clearances on
No. 4 cylinder.
(d) With the valves rocking on No. 3
cylinder, set the valve clearances on
No. 2 cylinder.
b. Request Direct Support maintenance to
service fuel injectors as follows:
1) Normally, defective injectors can be
isolated by loosening the pipe union nut
on each injector in turn while the engine is
running at approximately 800 rpm. As
each nut is loosened, fuel will not be
injected into the associated cylinder and,
as a result, the engine rpm will decrease if
the injector was previously functioning
normally. N the engine rpm remains
constant, the injector is probably
defective.
200 hrs
2) When installing a replacement injector
remember to include also a new copper
seating washer. These are special
washers and ordinary washers cannot be
used for this purpose. The recess in the
cylinder head, the faces of the washer,
and the corresponding face of the nozzle
holder cap must be perfectly dean to
ensure a leakproof seal. The importance
of injectors being seated squarely and
secured with the correct torque cannot be
emphasized too strongly. Even a slight
’canting’ of the injector can result in fouling
and distortion of the nozzle and needle
valve. This canting can also result in
leakage between injector and cylinder
head, with a resultant engine misfire.
3) Torque - To ensure squareness and free
entry of the nozzle into its bore, the
securing nuts must be tightened evenly
until a torque of 12 lb/ft (1.7 Nom) is
attained. Overtightening of these securing
nuts can result in a fractured injector
flange and/or a fouled nozzle needle
valve.
C-38
