Kohler Triad OHC TH520 Owner's Manual page 12

Carburetor Troubleshooting and Adjustments
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. Fuel mixture settings
are set at the factory and are not adjustable.
Troubleshooting Carburetor
If engine troubles are experienced that appear to be
fuel system related, check the following
troubleshooting hints.
• 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 and fuel pump for
restrictions or faulty components. Replace as
necessary.
• 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.
12
Adjust Carburetor
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before adjusting the low idle speed setting.
2. Low Idle Speed Setting: Place the throttle control
into the ''idle'' or ''slow'' position. The low idle
speed screw can be accessed through the air
cleaner. Remove the outer cover and look for the
grommet in the element cover. If the air cleaner is
assembled correctly, the grommet is aligned with
a corresponding hole in the air cleaner base,
directly above the low idle speed screw. Insert the
screwdriver (#1 Phillips) down through grommet to
make the adjustment. 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.
Low Idle Speed
Adjusting Screw
Figure 12. Carburetor (with Fuel Shutdown
Solenoid).