Onan NHC Series Operator's/Service Manual And Parts Catalog page 167

Linkage: The engine starts at wide open throttle.
The length of the linkage connecting the governor
arm to the throttle arm is adjusted by rotating the
ball joint housing. Adjust the length so that with
the engine stopped and tension on the governor spring,
the stop on the carburetor throttle lever is 1/32 inch
from the carburetor stop boss. This setting allows
immediate control by the governor after starting and
synchronizes travel of the governor arm and the throttle
shaft.
Speed Adjustment: The speed at which the engine
operates is determined by the tension applied to the
governor spring. Increasing spring tension increases
engine speed. Decreasing spring tension decreases
engine speed. The no load speed of the engine should
be slightly higher than the ispeed requirements of the
connected load. For example: If the connected load
is to turn, at 3510 rpm, set the no load speed of the
engine at about 3600rpm. Check speed with' a tacho-.
meter.
If a speed adjustment is needed, turn the speed adjust-
ing nut in to increase the speed or out to decrease
the speed (Figure 19).
Sensitivity Adjustment: The engine speed drop from no
load to f u l l load should be not less than 100 rpm. Check
the engine speed with no load .connected and again
after connecting f u l l load. Do not exceed 4000 rpm at
no load.
The sensitivity of the governor depends upon the
position of the arm end of the governor spring. A series
of holes in the governor arm provides for adjustment. To
increase sensitivity, move the spring toward the gover-
nor shaft. To decrease s e n s i t i v i t y , move the spring
toward the linkage end of the governor arm.
If the setting is too sensitive, a hunting condition
(alternate increase and decrease in engine speed) w i l l
result. If the setting is not sensitive enough, the speed
variation between no load and f u l l load conditions w i l l
be too great. Therefore, the correct sensitivity w i l l
result in the most stable speed regulation without
causing a surge condition.
Always recheck the speed adjustment after a s e n s i t i v i t y
adjustment. Increasing s e n s i t i v i t y w i l l cause a slight
decrease in speed and w i l l require a slight increase
in the governor spring tension. '
M O V E O O V E R N O R S P R I N O -
^°»E SENSITIVE ^
^ e S » S E N S I T I V E
G O V E R N O R
. S P R I N G
oodo~\
" • j — T H I S D I S T A N C E D E T E R M I N E S S E N S I T I V I T Y
G O V E R N O R A R M E X T E N S I O N
G O V E R N O R A R M — i
G O V E R N O R S H A F T
D E C R E A S E SPEED
. I N C R E A S E SPEED
G O V E R N O R L I N K A G E
M A X I M U M SPEED S T O P
D E C R E A S E SPEED
M I N I M U M S P E E D S T O P
F I G U R E 20. V A R I A B L E S P E E D GOVERNORS
21