12
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.
Adjust Carburetor
NOTE: Certified engines may have a fixed 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 making final settings (steps 2 and 3).
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.
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 12.
Carburetor Troubleshooting
and Adjustments
NOTE: Carburetor adjustments should be made only
after the engine has warmed up.
This engine is equipped with a fixed main jet
carburetor. See Figure 11.
Figure 11. Fixed Main Jet Carburetor.
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 low idle fuel adjusting needle
is also set at the factory and normally does not need
adjustment.
Troubleshooting
If engine troubles are experienced that appear to be
fuel system related, check the following areas before
adjusting the carburetor.
Make sure the fuel tank is filled with clean, fresh
gasoline.
Make sure the fuel tank cap vent is not blocked
and that it is operating properly.
If the fuel tank is equipped with a shut-off valve,
make sure it is open.
If the engine is equipped with an in-line fuel filter,
make sure it is clean and unobstructed. Replace
the filter if necessary.
Make sure fuel is reaching the carburetor. This
includes checking the fuel lines for restrictions or
faulty components, replace as necessary.
Figure 12. Optimum Low Idle Fuel Setting.
3.
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.
Choke Lever
Low Idle Fuel
Adjusting Needle
Low Idle Speed
Adjusting Screw
Lean
Rich
Adjust to
Midpoint
