Kohler 4CM21 Owner's Manual page 6

GOVERNOR ADJUSTMENT
The governor functions to maintain engine speed under changing load conditions and also acts as
a speed limiting device. Governor is set in the factory and further adjustment should not be required
unless linkage works loose or becomes disconnected. Readjustment should be made if engine surges
with changing load or if speed drops considerably when a normal load is applied.
Initial Adjustment: With engine stopped, loosen (do not remove) hex. nut securing governor arm to
governor cross shaft. Grasp end of cross shaft with pliers and turn shaft as far as possible in counter-
clockwise direction--tab on shaft will stop internally against governor gear mechanism. Hold shaft in
this position, pull governor arm all the way away from carburetor then retighten governor arm nut to
complete initial adjustment.
Speed Adjustment: This set must be operated at 1800 RPM. If frequency or overspeed condition is
suspected, check RPM with hand tachometer and readjust as follows: With constant speed arrangement,
loosen speed adjusting nut to decrease speed or tighten to increase speed.
GOVERNOR ARM
CROSS SHAFT
ARM
RETAINING
NUT
THROTTLE
LINKAGE
CARBURETOR
SPEED ADJUSTING NUTS
SPEED CONTROL BRACKET
FIGURE 7 - GOVERNOR COMPONENTS AND ADJUSTMENT POINTS
Sensitivity Adjustment: If speed drops considerably when a normal load is applied, governor should be
set for greater sensitivity. If set too sensitive, speed surging will occur with changing load. Governor
sensitivity is adjusted by repositioning governor spring in holes provided on arm and speed control
brackets. Increase tension on spring (and sensitivity) by moving spring hooks into holes spaced further
apart--conversely, decrease sensitivity by reducing tension on spring. Recheck engine speed and
readjust as needed after changing sensitivity.
COOLING
SYSTEM
Kohler Air- Vac cooling is used on this set. With this system, cooling air is drawn into the genera-
tor set compartment, circulated from the generator end, around the cooling fins and finally ejected as
heated air downward thru the Air- Vac scroll at the flywheel end of engine. High-temperature cutout on
cylinder head will stop the generator set if overheating occurs. Keep intake louvers, generator cooling
openings, cooling fins and scroll work clean and unobstructed at all tiDIes to prevent overheating--do not
operate with blower housing, scroll or cooling shrouds removed as this will also cause overheating.
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