TM 55-1930-209-14&P-21
f.
To vary engine power output, use injectors having different fuel output capacities. The fuel output for
various injectors is governed by helix angle of the plunger and type of spray tip used. Refer to Figure 5-6 for
identification of injectors and their respective plungers and spray tips.
CAUTION
The helix angle of plunger determines output and operating characteristics of a particular type of
injector. It is imperative that correct injectors are used for engine application. If injectors of
different types are mixed, erratic operation will result and may cause serious damage to engine or
to equipment which it powers.
g.
Each fuel injector control rack (Figure 5-10), is actuated by a lever on injector control tube which, in turn, is
connected to governor by means of a fuel rod. These levers can be adjusted independently on control tube, thus
permitting a uniform setting of all injector racks.
5-32 Fuel injector timing
a
Remove rocker arm cover.
b.
Each fuel injector has a circular disc pressed into a recess in front side of injector body for identification
purposes as illustrated in Figure 5-10. The identification tag indicates nominal output of injector in cubic millimeters. A
horizontal bar on injector identification tag between "GM" and injector size indicates current needle valve injector. Use a
timing gage with a dimension of 1.484 inches when timing injector.
c.
Time fuel injectors as illustrated in Figure 5-11.
d.
Install rocker arm cover.
5-33 Fuel Injector removal, test and disassembly
a.
Removal
(1)
Remove rocker arm cover.
(2)
Remove two fuel tubes (Figure 5-12).
CAUTION
Immediately after removal of fuel pipes from injectors, cover filter caps with shipping caps to
prevent dirt from entering injector. Also, cover fuel pipes and connectors to prevent entry of dirt
or foreign material.
(3)
Crank engine with starting motor to bring push rod ends, outer ends of injector, and valve rocker arms
in line horizontally.
(4)
Remove rocker arm shaft bracket bolts and fuel injector as illustrated in Figure 5-12.
5-30
