GMC 1976 ZEO 6083 Maintenance Manual page 703

24C- 26 ONAN MOTOR GENERATOR
increase and decrease in speed (hunting). A lean car-
buretor adjustment may also cause hunting. Springs
of all kinds have a tendency to lose their calibrated
tension through fatigue after long usage. If all gover-
nor and carburetor adjustments are properly made,
and the governor action is still erratic, replacing the
spring with a new one and resetting the adjustments
will usually correct the trouble .
1 . Adjust the carburetor idle needle with no load
connected.
2. Adjust the carburetor main jet for the best fuel
mixture while operating the set with a full rated load
connected.
3 . Adjust the length of the governor linkage and
check linkage and throttle shaft for binding or exces-
sive looseness.
4. Adjust the governor spring tension for rated
speed at no load operation.
5 . Adjust the governor sensitivity .
6. Recheck the speed adjustment .
7. Set the carburetor throttle stop screw.
LINKAGE
The engine starts at wide open throttle . The
length of the linkage connecting the governor arm to
the - i brottle shaft and lever is adjusted by rotating the
THROTTLE
STOP SCREW
Figure 38-Governor Adjustments
ball joint. Adjust this length so that with the engine
stopped and tension on the governor spring, the stop
on the carburetor throttle lever just contacts the
stop . This setting allows immediate control by the
governor after starting. It also synchronizes travel of
the governor arm and the throttle shaft.
SPEED ADJUSTMENT
With the warmed-up unit operating at no load,
adjust the tension of the governor spring (See figure
38) . Turn the speed adjusting nut to obtain a voltage
and speed reading within the limits shown .
SENSITIVITY ADJUSTMENT
Referring to Figure 38 check the voltage and
speed, first with no load connected and again with a
full load . Adjust the sensitivity to give the closest
regulation (least speed and voltage difference be-
tween no load and full load) without causing a hunt-
ing condition .
To increase sensitivity (closer regulation), shift
the. spring toward the governor shaft.
An adjustment for too much sensitivity will cause
alternate increase and decrease of engine speed
(hunting).
To decrease sensitivity, shift the spring toward
the outer end of the governor arm . Too little sen-
sitivity will result in too much difference in speed
between no load and full load conditions .
A-1628
VOLTAGE CHART 120 VOLT
FOR CHECKING
I PHASE
GOVERNOR REGULATION
2 WIRE
MAXIMUM
126
NO-LOAD VOLTAGE
MINIMUM x'°
110
FULL- LOAD VOLTA
SPEED CHART FOR CHECKING
GOVERNOR REGULATION
MAXIMUM NO-LOAD SPEED (RPM) 1890
HERTZ (CURRENT FREQUENCY) 63
MINIMUM FULL-LOAD SPEED (RPM) 1770
HERTZ 59