Carburetor Adjustments - Kohler Magnum M8 Owner's Manual

Carburetor adjustments should be made only after the engine has warmed up.
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 exhibits conditions like
those found in the table, it may be
necessary to adjust the carburetor.
Turning the adjusting needles in
(clockwise) decreases the supply of
fuel to the carburetor. This gives a
leaner fuel-air mixture. Turning the
adjusting needles out (counterclock­
wise) increases the supply of fuel to
the carburetor. This gives a richer
fuel-air mixture.
An incorrect setting can cause a foul­
ed spark pi ug, overheating, excessive
valve wear, and other problems. See
your Kohler Engine Service Dealerfor
assistance.
To Adjust Carburet or
1. Stop the engine. Turn the main fuel
and idle fuel adjusting needles
clockwise until they bottom lightly.
Idle
Speed
Screw
Idle
Fuel
Needle
CAUTION: The ends of the main
fuel and idle fuel adjusting needles
are tapered to critical dimensions.
Damage to needles and seats will
result if the needles are forced.
2. Preliminary Settings: Turn the
main fuel and idle fuel adjusting
needles out from lightly bottomed
as follows:
Engine Model
Main Fuel
M8 (8 hpj 2
turns
M10 (10 hpj 1-1/2 turns
M12 (12 hpj 1-112
turns
M14(14hp) 2-112
turns
M16 (16 hpj 2-1/2
turns
6

CARBURETOR ADJUSTMENTS

1. Black sooty exhaust smoke',
engine sluggish.
2. Engine misses and backfires at
high speed.
3. Engine starts and then stops
under cold weather conditions.
4. Engine runs roughly or stalls
at idle speed.
•
*If black exhaust smoke is noted, check the air cleaner first. An apparent
"overrich" mixture can actually be due to a clogged air cleaner element.
If, after element is replaced, black smoke or other problems continue,
adjust the carburetor immediately.
3. Start the engine and run at half­
throttle for 5-10 minutes to warm
up. Engine must be warm before
making final settings (steps 4-6).
Main Fuel
4. Final Setting - Main Fuel: Place
Needle
throttle in wide open position; and
if pOSSible, place engine under
load. Turn main fuel adjusting
needle out from preliminary set­
ting until the engine speed de­
creases (rich). Note the position of
the needle.
Now turn the adjusting needle in.
The engine speed may increase,
then it will decrease as the needle
is turned in (lean). Note the posi­
tion of the needle.
Adjust To
Midpoint
Rich
Idle Fuel
1-1/4
turns
2-1/2 turns
2-1/2 turns
2-1/2
turns
2-1/2 turns
Pos$lble Cause/Probable Solution
Condition
1. Main fuel mixture too rich. Turn
2. Main fuel mixture too lean.
3. Main fuel mixture too lean.
4. Idle speed too low or improper
5. Final Setting - Idle Fuel: Place
6. Idle Speed Setting: Place throttle
.
.,-.. .
Lean "
.
I
I
•
•
main fuel adjusting needle
clockwise.
Turn main fuel adjusting needle
counterclockwise.
Turn main fuel adjusting needle
counterclockwise.
idle fuel mixture. Turn idle
speed adjusting screw, then
idle fuel adjusting needle.
Set the adjusting needle midway
between the rich and lean settings
noted.
throttle into idle or slow position.
Set idle fuel adjusting needle using
the same procedure as in step 4.
NOTE: To ensure best results when
setting idle fuel mixture, the idle
speed must not exceed 1500 RPM.
Typical idle speed is 1200' RPM.
See step 6.
into idle or slow position. Set idle
(t
speed to 1200* RPM 75 RPM) by
turning the idle speed adjusting
screw in or out.
See your Kohler Engine Service
Dealer for assistance with carbure­
tor and idle speed adjustments.
.
*Refer to equipment manufac­
turer's instructions for specific idle
speed settings.
..