f. If the governor cannot operate the throttle lever
adjusting screw (11) and compensate for speed change
with the speed adjusting screw (10).
on the carburetor through the full operating range, it will
d. When the governor range of action is properly
be necessary to adjust the length of the throttle rod (2)
by loosening the nut (3) and adjusting the position of the
adjusted, allow the engine to run at governed speed, no
ball joint (4).
load, and check for surging. If surging is noted, turn in
g. When the governor adjustment is completed,
the surge adjusting screw (7) just far enough to
eliminate the surging.
tighten the speed adjusting lock screw (9) to lock the
e. The surge adjustment can also be made by
cam in position.
Make sure all locking nuts are
using the tachometer. With the engine running at
h. If the governor cannot be adjusted, refer
governed speed, no load, turn in the surge adjusting
screw (7) until the engine speed increases 10 to 20 rpm
problem to direct support maintenance.
and tighten the locking nut. If the carburetor and linkage
are properly adjusted, surge will disappear.
Section X. MAINTENANCE OF COOLING SYSTEM
radiator clean and free from bugs, dirt, and debris. It is
also necessary to keep the interior of the radiator and
a. The engine cooling system is a conventional
the engine block flushed out to prevent accumulations of
rust and scale which can prevent proper heat transfer.
automotive type in which coolant is circulated through
the cylinder block to remove the combustion heat from
4-29. Cleaning and Flushing the Cooling System
the operating parts of the engine. The water is then
passed through the radiator, which acts as a large heat
a. Clean the exterior of the radiator by flushing a
exchanger to dissipate the heat to the atmosphere. The
stream of water through it in a direction opposite that of
water pump maintains the flow of coolant through the
the cooling fan flow. Since this engine uses a pusher
type fan, it is necessary to squirt the water from the
b. A thermostat is installed in the engine to prevent
outside of the radiator inward toward the engine. Cover
the engine with a piece of plastic film to prevent
the flow of coolant into the radiator when the engine is
saturating the components before attempting to flush the
cold. Instead, the coolant is bypassed directly to the
exterior of the radiator.
water pump and recirculated into the block without being
cooled in the radiator. In this way, the engine heats
b. Disconnect the hoses connecting the engine and
more rapidly, providing efficient operation more quickly.
radiator. With the radiator cap closed tightly, use a
When the coolant in the cylinder block reaches
flushing gun as shown in figure 4-13 to reverse-flush the
operating temperature, the thermostat opens and the
radiator. Fill the radiator with water, then blow out the
coolant is forced to flow through the radiator.
water with compressed air, applying pressure slowly to
c. To ensure efficient operation of the cooling
prevent radiator damage. Repeat several times until the
expelled flushing stream is clear.
system, it is important to keep the exterior of the