Troubleshooting Checklist - Kohler command pro CH742 Service Manual

Engines in this series are equipped with a two-barrel side-draft carburetor with fi xed main jets on a matching intake
manifold. Carburetor features a self-relieving choke, serviceable slow jets, main jets, accelerator pump, and a fuel
shutdown solenoid.

Troubleshooting Checklist

When engine starts hard, runs roughly or stalls at low
idle speed, check following areas before adjusting or
disassembling carburetor.
1. Make sure fuel tank is fi lled with clean, fresh
gasoline.
2. Make sure fuel tank cap vent is not blocked and that
it is operating properly.
3. Make sure fuel is reaching carburetor. This includes
checking fuel shut-off valve, fuel tank fi lter screen,
in-line fuel fi lter, 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, misfi ring, loss
of speed and power, governor
hunting, or excessive throttle
opening).
Engine runs lean (indicated by
misfi ring, loss of speed and power,
governor hunting, or excessive
throttle opening).
Fuel leaks from carburetor.
24 690 34 Rev. D
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 speed improperly adjusted.
Clogged air cleaner.
Choke partially closed during
operation.
Float level is set too high.
Dirt under fuel inlet needle.
Bowl vent or air bleeds plugged.
Float level is set too low.
Idle holes plugged; dirt in fuel delivery
channels.
Float level is 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.
Clean or replace air cleaner.
Check choke lever/linkage to ensure
choke is operating properly.
Adjust fl oat 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.
Adjust fl oat according to Float
Replacement Procedure.
Remove low idle fuel adjusting
needle. Clean main fuel jet and all
passages; blow out with compressed
air.
Adjust fl oat 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
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