Kohler COMMAND CV11-16 Service Manual page 35

Adjustment
NOTE: Carburetor adjustments should be made only
after the engine has warmed up.
The carburetor is designed to deliver the correct
fuel-to-air mixture to the engine under all operating
conditions. The main fuel jet is calibrated at the factory
and is not adjustable*. The idle fuel adjusting needle
is also set at the factory and normally does not need
adjustment.
*NOTE: Engines operating at altitudes above
approximately 1830 m (6000 ft.) may require
a special ''high altitude'' main jet. Refer to
''High Altitude Operation'' later in this section.
If, however, the engine is hard-starting or does not
operate properly, it may be necessary to adjust or
service the carburetor.
Low Idle
Speed Screw
Low Idle
Fuel Needle
Figure 5-4. Fixed Main Jet Carburetor.
Walbro Carburetor Adjustment
NOTE: Certifi ed engines may have a fi xed idle or
limiter cap on the idle fuel adjusting needle.
Step 2 can only be performed within the limits
allowed by the cap.
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before doing step 2.
2. Low Idle Fuel Needle Setting: Place the throttle
into the "idle" or "slow" position.
Turn the low idle fuel adjusting needle out
(counterclockwise) from the preliminary setting
until engine speed decreases (rich). Note the
position of the needle.
Fuel System and Governor
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. See Figure 5-5.
Adjust to Midpoint
Rich
Figure 5-5. Optimum Low Idle Fuel Setting.
Nikki Carburetor Adjustment
NOTE: Certifi ed engines have the idle mixture preset
and sealed at the factory. No adjustment is
possible.
Low Idle Speed Setting
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before doing step 2.
2. 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 1200 RPM (±75 RPM).
Section 5
Lean
5
5.5