5.16
Section 5
Fuel System and Governor
• One end of the cross shaft protrudes through the
crankcase. The rotating action of the cross shaft
is transmitted to the throttle lever of the
carburetor through the external throttle linkage.
See Figure 5-36.
Initial Adjustment Procedure
Make this adjustment whenever the governor arm is
loosened or removed from the cross shaft. See Figure
5-36 and adjust as follows:
1. Make sure the throttle linkage is connected to the
governor arm and the throttle lever on the
carburetor.
2. Loosen the hex nut holding the governor lever to
the cross shaft.
3. Move the governor lever
toward
the carburetor
as far as it will go (wide open throttle) and hold
in this position.
4. Insert a long thin rod or tool into the hole on the
cross shaft and rotate the shaft clockwise
(viewed from the end) as far as it will turn, then
torque the hex nut to
7.3 N·m (65 in. lb.)
.
High Speed (RPM) Adjustment
1. With the engine running, move the throttle
control to
fast
. Use a tachometer to check the
RPM speed.
2. Turn the inner adjustment screw outward to
decrease, or inward to increase the RPM speed.
Check RPM with a tachometer.
3. Stop when the desired RPM speed is obtained.
Figure 5-36. Governor Linkage (Air Cleaner
Removed for Clarity).
• When the engine is at rest, and the throttle is in
the
fast
position, the tension of the governor
spring holds the throttle plate open. When the
engine is operating, the governor gear assembly
is rotating. The force applied by the regulating
pin against the cross shaft tends to close the
throttle plate. The governor spring tension and
the force applied by the regulating pin balance
each other during operation, to maintain engine
speed.
• When load is applied and the engine speed and
governor gear speed decreases, the governor
spring tension moves the governor arm to open
the throttle plate wider. This allows more fuel
into the engine, increasing the engine speed. As
the speed reaches the governed setting, the
governor spring tension and the force applied by
the regulating pin will again offset each other to
hold a steady engine speed.
Adjustments
NOTE: Do not tamper with the governor setting.
Overspeed is hazardous and could cause
personal injury.
General
The governed speed setting is determined by the
position of the throttle control. It can be variable or
constant, depending on the engine application.
Governed
Idle Spring
Governor
Spring
Governor
Lever
Cross Shaft
Figure 5-37. High Speed RPM Adjustment (Air
Cleaner Removed For Clarity.
High Speed (RPM)
Adjustment Screw
