warms up. Rough operation of a cold engine indicates
the need of a choke adjustment. See Figure 32.
Sisson Choke: Adjust the Sisson choke by loosening
the screw holding the choke wire and repositioning it
to obtain smooth cold engine performance.
Thermo-Magnetic Choke: Adjust the thermo-
magnetic choke by loosening the screw and rotating
the entire assembly to obtain smooth cold engine
operation.
GOVERNOR
ADJUSTMENTS
The governor system automatically regulates the
engine speed regardless of load conditions; the
engine speed, in
turn,
determines the voltage and
frequency of the generator current. Onan uses a
standard 10-ball governor on NH generating sets.
Always perform governor adjustments concurrently
with carburetor adjustments. The proper frequency at
no load is 61 hertz and at full load is 59 hertz. The
frequency spread can be reduced as long as no
surging develops.
Check the governor arm, linkage, throttle shaft and
lever for binding or excessive wear at connecting
points. A binding condition at any point will cause the
governor to act slowly and regulation will be poor.
Excessive looseness will cause a hunting condition
and regulation will be erratic. Work the arm back and
forth several times by hand while the engine is idle. If
either of these conditions exists, determine the cause
and adjust or replace parts as necessary. See Figure
33.
VACUUM
BOOSTER-
THIS
DISTANCE
DETERMINES
SENSITIVITY
CARBURETOR
THROTTLE ARM-
CARBURETOR
THROTTLE
PLATE-
GOVERNOR
ARM
ADJUSTING STUD
GOVERNOR ADJUSTMENT
FIGURE 33. GOVERNOR ADJUSTMENTS
23
To Next Page
Loading...
Need help?
General
