Kohler command pro CH940 Service Manual page 31

Engines in this series are equipped with a two-barrel,
side-draft carburetor with fixed main jets on a matching
intake manifold. Carburetor features a self-relieving
choke, serviceable slow jets, main jets, bowl drain and a
fuel shutdown solenoid.
Troubleshooting Checklist
When engine starts hard, runs rough, or stalls at low
idle speed, check these areas before adjusting or
disassembling carburetor.
1. Make sure fuel tank is filled with clean, fresh
gasoline.
2. Make sure fuel tank cap vent is not blocked and is
operating properly.
3. Make sure fuel is reaching carburetor. This includes
checking fuel shut-off valve, fuel tank filter screen,
in-line fuel filter, fuel lines and fuel pump for
restrictions or faulty components as necessary.
Troubleshooting-Carburetor Related Causes
Condition
Engine starts hard, runs rough, or
stalls at idle speed.
Engine runs rich (indicated by black,
sooty exhaust smoke, misfiring, loss
of speed and power, governor
hunting, or excessive throttle
opening).
Engine runs lean (indicated by
misfiring, loss of speed and power,
governor hunting, or excessive
throttle opening).
Fuel leaks from carburetor.
62 690 01 Rev. J
4. Make sure air cleaner base and carburetor are
5. Make sure air cleaner element (including precleaner
6. Make sure ignition system, governor system,
Possible Cause
Low idle fuel mixture (some models)/
speed improperly adjusted.
Clogged air cleaner.
Choke partially closed during
operation.
Low idle fuel mixture is improperly
adjusted.
Float level is set too high.
Dirt under fuel inlet needle.
Bowl vent or air bleeds plugged.
Leaky, cracked, or damaged float.
Low idle fuel mixture is improperly
adjusted.
Float level is set too low.
Idle holes plugged; dirt in fuel delivery
channels.
Float level set too high.
Dirt under fuel inlet needle.
Bowl vents plugged.
Carburetor bowl gasket leaks.
KohlerEngines.com
securely fastened to engine using gaskets in good
condition.
if equipped) is clean and all air cleaner components
are fastened securely.
exhaust system, and throttle and choke controls are
operating properly.
Adjust low idle speed tab, then adjust
low idle fuel needle.
Clean or replace air cleaner.
Check choke lever/linkage to ensure
choke is operating properly.
Adjust low idle fuel needle (some
models).
Adjust float according to Float
Replacement Procedure.
Remove needle; clean needle and
seat and blow with compressed air.
Remove low idle fuel adjusting
needle. Clean vent, ports, and air
bleeds. Blow out all passages with
compressed air.
Submerge float to check for leaks.
Adjust low idle fuel needle (some
models).
Adjust float according to Float
Replacement Procedure.
Remove low idle fuel adjusting
needle. Clean main fuel jet and all
passages; blow out with compressed
air.
Adjust float according to Float
Replacement Procedure.
Remove needle; clean needle and
seat and blow with compressed air.
Blow out with compressed air.
Replace gasket.
Fuel System
Conclusion
31