Chevrolet 70 1969 Series, Shop Manual

Page: 358 / 913

ENGINE FUEL SYSTEM 6M-31
Figure 20—Adjusting Idle Speed
spring shown in type "A ,"o f figure 19, or by chang­
ing the thickness of the shim pack in the governors
with the short spring shown in type ”B," of figure 19.
Adjust high speed spring in type "B" governor as
instructed later in this section under "High Speed
Spring Adjustment."
Lubrication
The governor is lubricated by a spray of pres­
surized lubricating oil from the blower rear end
plate to the blower timing gears which distribute
this oil to various parts of the governor. Oil splash
from the gear train provides lubrication for the
governor weights and shaft. Excess oil overflows
into the gear train compartment and returns to the
crankcase.
C H E C K IN G G O V E R N O R O P E R A T IO N
Governor difficulties are usually indicated by
speed variations of the engine; however, it does not
necessarily mean that all such speed fluctuations
are caused by the governor. Therefore, when im­
proper speed variations appear, the unit should be
checked as follows:
1. Make sure the speed changes are not the re­
sult of excessive load fluctuations.
2. Check engine to be sure that all cylinders
are firing properly. If any cylinder is not firing
properly, the injector must be removed, tested
and if necessary, reconditioned.
3. Check for bind that may exist in the gov­
ernor operating mechanism or in the linkage be­
tween the governor and injector control tube.
With the fuel rod connected to the injector
control tube lever, the mechanism should be free
from bind throughout the entire travel of the injec­
tor racks. If friction exists in the mechanism, it
may be located and corrected as follows:
1. If an injector rack sticks or moves too hard,
it may be due to the injector hold down clamp being
too tight or improperly positioned. To correct this
condition, loosen the injector clamp, reposition, and
tighten to 25 to 30 foot-pounds torque.
2. A binding injector may result from internal
dirt accumulation, defective plunger and bushing,
or a bent injector rack. The injector must be re­
moved and tested as outlined in this section.
3. An injector rack may bind as the result of
an improperly positioned control rack lever. Loos­
en control rack adjusting screws. If this relieves
the bind, relocate the lever on the control tube and
position the rack as outlined in this section.
4. The injector control tube may bind in its
support brackets, thus preventing free movement
of the injector racks to their no-fuel position due
to tension of the return spring.
This condition may be corrected by loosening
and realigning the control tube supporting brackets.
If the control tube support brackets were loosened,
realigned and tightened, the injector racks must
be repositioned as outlined in this section.
5. A bent control tube return spring may cause
friction in the operation of the injector control
tube. If a control tube return spring has heen bent
or otherwise distorted, install a new spring.
6. Check for bind in pin which connects the
fuel rod to the injector control tube lever and re­
place pin if necessary.
If, after making the preceding checks, the
governor fails to control the engine properly, the
governor should be removed and reconditioned.
H IG H S PEE D SPRING A D J U S T M E N T
All governors are properly adjusted before
leaving the factory. However, if the governor has
been reconditioned or replaced, and to ensure the
engine speed will not exceed the recommended no-
load speed of 3,000 rpm, the maximum no-load
speed may be set as follows:
1. Start engine and after attaining operating
temperature remove load from engine.
2. Place engine throttle control lever into the
"Full Speed” position and note engine speed.
3. Stop engine and if necessary, adjust to the
desired No-Load speed as follows:
a. Remove high speed spring retainer, high
speed spring and plunger assembly.
C A U T IO N : Be careful not to jar
assembly while it is being removed to
prevent the low speed spring and cap
from dropping into governor.
CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L