GMC 4000 Series Service Manual page 376

6. Place a quantity of adjusting spacers (4, fig.
15) between governor sleeve (8, fig. 15) and outer
spring (3, fig. 15), so that when supply pump with
gasket is held in installed position, the outer spring
can be turned but has no end play. Then, remove
supply pump and add adjusting spacers with total
thickness of 0.C59 to 0.079 inch togiveproper pre­
compression on outer spring.
NOTE: Do not install outer spring (3, fig. 15)
when checking spacer pack for inner spring (7, fig.
15) or install inner spring when checking spacer
pack for outer spring.
7. Reinstall the inner and outer governor
springs with their respective spacers as previ­
ously determined.
8. Reinstall the fuel supply pump and new gas­
ket, taking care that the inner and outer spring
guides (1 and 11, fig. 35) do not fall off the supply
pump insert. The flat (2, fig. 35) on the fuel pump
drive shaft must engage with the gear in the supply
pump. Exercise care so that seal (9, fig. 35) is not
damaged. Tighten supply pump mounting bolts to
5 to 6 foot-pounds torque.
9. Reinstall governor cover using new gasket
and the four bolts. Connect inlet and outlet fuel
lines and controls.
10. Start engine and adjust idle speed to 625-
675 rpm with full accessory load. Set high speed
to correct No-Load Rpm as specified, if necessary.
NOTE: Range of idle screw adjustment is
lim ited. Too high adjustment may allow droop
screw (fig. 32) to rest against excess fuel piston
stop plate and cause erratic idle.
11. Check the operation of the fuel injection
pump governor throughout the speed range. Be
sure control rod movement is not restricted by
governor cover right front cap screw.
12. Make sure that full travel of the acceler­
ator lever and stop linkage can be obtained.
INTERNAL GOVERNOR SPRING PACK
ADJUSTMENT (USING SPECIAL TOOL)
A special tool (J-22452) is available for use to
accurately select injection pump governor spring
spacers. The tool serves in determining the re­
quired spacers, both for the inner (high speed) and
the outer (low speed) spring. Refer to figure 15 for
location of spacers. Whenever occasion arises for
checking either of the governor springs, the other
spring should also be checked. Tool may be used
without removing the injection pump assembly
from engine.
IMPORTANT: If other tools are used to select
spring spacers, it may be necessary to use feeler
gauge to measure space. Also, the available tool
may be graduated in m illim eters rather than in
inches. For conversion purposes 1 MM. is equal
to approximately 0.040 inch.
G M C S E R V I C E M A N U A L
FUEL INJECTION SYSTEM— TORO-FLOW ENGINE
lection, do not use the supply pump gasket between
tool and housing.
Governor Spring Pack Adjustment (Without Special
Tool)" previously in this section.
used in following text, unless otherwise specified.
(6), which were removed in disassembly procedure,
in the cavity provided in tool, then place tool in
position with spring guide (5) inserted in spring
and tool body seated against governor housing as
shown in figure 17. Use short supply pump mount­
ing bolt to temporarily secure tool flange to the
pump housing.
stop lever is in the "STOP" position (fig. 16), then
while holding governor sleeve forward, read the
inner spring graduated scale to determine if spring
spacers should be added or removed, and in what
thickness (fig. 17). The inner spring can be turned
but has no end play.
the tool scale is indexed with line when the parts
are held in firm contact without compressing the
inner spring. Spacers (6) are available in seven
different thicknesses and may be selected in vary­
ing combinations to provide proper adjustment of
inner spring. Tool scale will indicate a gap of 0.089
to 0.108 inch with proper spacers in place.
NOTE: When using the tool to make spacer s e ­
1. Perform Steps 1 through 4 under "Internal
NOTE: Refer to figure 15 for key numbers
2. Place inner spring guide (5) and spacers
3. Check engine stop mechanism to be sure
4. Add or remove inner spring spacers (6) so
Figure 17— Special Tool Application for Selecting
Inner (High Speed) Spring Spacer
Sec. 6M
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