Kohler K91 Service Manual page 29

Plain Washer (2)
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L ,j). .
Fillister Head Sems
Screws (2)
Figure 6-3. I nsta l l i n g Fuel P u m p .
NOTE : Make sure that the fuel pump lever is posi­
tioned above the camshaft . Damage to the fuel
pump and severe damage to the engine could re­
sult if the lever is positioned below the camshaft .
Make sure that the flat washers are installed next
to the mounting flange to prevent damage from
the lock washers .
If a metal bodied pump was replaced by a pl astic
bodied p u m p , make sure that the old thick gasket
is discarded and the new thin gasket is used .
Torque screws to
3. 37 - 45 i n .
4 . Con nect fuel lines t o in let a n d outlet fitti ngs .
CARBURETOR - GASOLI N E
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WARNING:
Explosive Fue l l
Gasoline may b e present in the carburetor and fuel
system. Gasoline is extremely flammable and
explode if ignited. Keep sparks, open flames, and
other sources of ignition away from the engine. Dis­
connect and ground the spark plug lead to prevent
the possibility of sparks from the ignition system.
Adj u stment
The carburetor is designed to deliver the correct
fuel/air mixture to the engine under all operating
conditions. Carburetors are set at the factory and
normally do not need adjustment . If the engine
exh ibits conditions like those found in the table
that fol lows , it may be necessary to adjust the
carburetor.
In genera l , t u rning the adjusting needles i n (clock­
wise) decreases the supply of fuel to the carbure-
tor . This gives a
the adjusting needles
creases the supply of fuel to the carburetor . This
gives a
dles m idway between the lean and rich positions
will usually give the best results . Adjust the carbu­
retor as follows :
1 .
\
NOTE : The tip of the low idle fuel and high idle fuel
adjusting needles are tapered to critical dimensions.
Fuel Pump
Mounting Flange
Damage to the needles and the seats in carburetor
body will result if the needles are forced .
2 .
3.
4 .
Place the throttle into the .. fast " position . If possi­
ble, place the engine u nder load .
l i b .
Turn the high idle fuel adjusting needle
terclockwise) from the prelim inary setting until the
engine speed decreases (rich) . Note the position
of the needle.
Now turn the adjusting needle
engine speed m ay increase , then it will decrease
as the needle is turned in (lean) . Note the position
it
can
of the need le.
Set the adjusting needle
and lean settings. See Figure 6-5 .
5 .
NOTE: The actual low idle speed depends on the
appl ication . Refer to the equipment manufacturer ' s
instructions for specific low idle speed settings.
The recom mended low idle speed for Basic En­
gines is 1 200 rpm . To ensure best results when
setting the low idle fuel needle, the low idle speed
m ust not exceed 1 500 rpm .
leaner fuel-to-air mixt ure . Turning
out (counterclockwise) in­
richer fuel-to-air mixture . Setting the nee­
With the engine stopped , turn the low idle fuel
adjusting needle in (clockwise) until it bottoms
lightly.
Preliminary Settings: Turn the adjusting needles
out (cou nterclockwise) from lightly bottomed
according to the table shown in Figure 6-4 .
Start the engine and run at half throttle for five
to ten min utes to warm u p . The engine m ust
be warm before making final settings (Steps 4 ,
5 , 6 , and 7) .
High Idle Fuel Needle Settin g : This adjustment
is required only for adjustable high idle ( main)
jet carburetors . If the carbu retor is a fixed
main jet type , go to step 5 .
midway
Low Idle Speed Setti n g : Place the throttle con­
trol into the Ii idl e " or .. slow " position . Set the
low idle speed to 1 2 00 rpm
by turning the low idle speed adjusting screw
in or out. Check the speed using a tachome­
ter.
out (coun­
i n (clockwise) . The
between the rich
(+ or - 75 rpm)
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6 . 3
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