Onan NHC Series Operator's/Service Manual And Parts Catalog page 228

GOVERNOR SYSTEM
GOVERNOR ADJUSTMENT
Where engine speed is governor controlled, the governor
is set at the factory to allow a nominal engine speed
of 2400 rpm at no load operation (unless another speed
is specified when the engine is ordered). Proper gover-
nor adjustment is one of the most important factors in
maintaining the power and speed- desired from the
engine.
Before making governor adjustment, run the engine
about 15 minutes to reach normal operating temperature.
It is d i f f i c u l t to determine i f , after long usage, the
governor spring has become fatigued. I f , after properly
making a l l other adjustments, the regulation is s t i l l
erratic, install a new spring (Figure 19).
A tachometer for checking engine speed is required
for accurate governor adjustment.
Check the governor arm, linkage, throttle shaft and
lever for binding or excessive wear at connecting
points. A binding condition at any point w i l l cause
the governor to act slowly and regulation w i l l be poor.
Excessive looseness w i l l cause a hunting condition
and regulation w i l l be erratic. Work the arm back and
forth several times by hand while the engine is . idle.
If either of these conditions exist, determine the cause
and adjust or replace parts as needed.
Procedure:
1. Adjust the carburetor main jet for the best fuel
mixture at f u l l load operation.
2. Adjust the carburetor idle needle with no load
connected.
3. Adjust the length of the governor linkage.
4. Check the governor linkage and throttle shaft
for binding or excessive looseness.
5. Adjust the governor spring tension for nominal
engine speed at no load operation.
6. Check the rpm drop between no load and f u l l load
operation and adjust the governor sensitivity as
needed.
7. Recheck the speed adjustment.
8. Set the carburetor throttle stop screw.
CARBURETOR
THROTTLE ARM-
CARBURETOR
THROTTLE
PLATE-
GOVERNOR
ARM
ADJUSTING STUD
GOVERNOR ADJUSTMENT
F I G U R E 19. G O V E R N O R A D J U S T M E N T S
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