Filter
Top Products
l Make sure fuel is reaching the carburetor. This
includes checking the fuel lines and fuel pump for
restrictions or faulty components, replace as
necessary.
l Make sure the air cleaner element is clean and all
air cleaner element components are fastened
securely.
If, after checking the items listed above, the engine is
hard to start, runs roughly, or stalls at low idle speed, it
may be necessary to adjust or service the carburetor.
Kohler Carburetor Adjustment
1. With the engine stopped, turn the low and main
fuel adjusting needles in (clockwise) until it
bottoms lightly.
NOTE: The tip of the idle fuel and main idle fuel
adjusting needles are tapered to critical
dimensions. Damage to the needles and
the seats in carburetor body will result if
the needles are forced.
2. Preliminary Settings: Turn the adjusting needles
out (counterclockwise) from lightly bottomed as
follows:
Kohler Adjustable Jet
Low Idle
High Idle 1
K241
K301
K321
K341
2-I/2 turns
2-1 I2 turns
2-l I2 turns
2-l I2 turns
2 turns
2 turns
3-l/4 turns
3-l I2 turns
3. Start the engine and run at half throttle for 5 to 10
4
minutes to warm up. The engine must be warm
before making final settings.
Main Fuel Needle Setting: This adjustment is
required for adjustable main jet carburetors only.
If the carburetor is a fixed main jet type refer to
Walbro adjustment.
Place the throttle into the wide-open or “fast”
position. If possible, place the engine under load.
Turn the main fuel adjusting needle out
(counterclockwise) from the preliminary setting
until the engine speed decreases (rich). Note the
position of the needle.
Now turn the adjusting needle in (clockwise). The
engine speed may increase, then it will decrease
as the needle is turned in (lean). Note the position
of the needle.
Set the adjusting needle midway between the
rich and lean settings.
5. Low Idle Speed Setting: Place the throttle
control into the “idle” or “slow” position. Set the
low idle speed to 1200 RPM* (+ 75 RPM) by
turning the low idle speed adjusting screw in or
out. Check the speed using a tachometer.
*NOTE: The actual low idle speed depends on
the application - refer to equipment
manufacturer’s recommendations. The
recommended low idle speed for basic
engines is 1200 RPM. To ensure best
results when setting the low idle fuel
needle, the low idle speed must not
exceed 1500 RPM.
6. Low Idle Fuel Needle Setting: Place the throttle
into the “idle” or “slow” position.
Turn the idle fuel adjusting needle out
(counterclockwise) from the preliminary setting
until the engine speed decreases (rich). Note the
position of the needle.
Now turn the adjusting needle in (clockwise). The
engine speed may increase, then it will decrease
at the needle is turned in (lean). Note the position
of the needle.
Set the adjusting needle midway between the
rich and lean settings.
Adjust To
Midpoint
Lean
Rich
-0-B
Figure 8.
7. Recheck idle speed using a tachometer. Readjust
speed as necessary.
11