Fuel System
31
62 690 01 Rev. J
KohlerEngines.com
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
Possible Cause
Conclusion
Engine starts hard, runs rough, or
stalls at idle speed.
Low idle fuel mixture (some models)/
speed improperly adjusted.
Adjust low idle speed tab, then adjust
low idle fuel needle.
Engine runs rich (indicated by black,
sooty exhaust smoke, misfiring, loss
of speed and power, governor
hunting, or excessive throttle
opening).
Clogged air cleaner.
Clean or replace air cleaner.
Choke partially closed during
operation.
Check choke lever/linkage to ensure
choke is operating properly.
Low idle fuel mixture is improperly
adjusted.
Adjust low idle fuel needle (some
models).
Float level is set too high.
Adjust float according to Float
Replacement Procedure.
Dirt under fuel inlet needle.
Remove needle; clean needle and
seat and blow with compressed air.
Bowl vent or air bleeds plugged.
Remove low idle fuel adjusting
needle. Clean vent, ports, and air
bleeds. Blow out all passages with
compressed air.
Leaky, cracked, or damaged float.
Submerge float to check for leaks.
Engine runs lean (indicated by
misfiring, loss of speed and power,
governor hunting, or excessive
throttle opening).
Low idle fuel mixture is improperly
adjusted.
Adjust low idle fuel needle (some
models).
Float level is set too low.
Adjust float according to Float
Replacement Procedure.
Idle holes plugged; dirt in fuel delivery
channels.
Remove low idle fuel adjusting
needle. Clean main fuel jet and all
passages; blow out with compressed
air.
Fuel leaks from carburetor.
Float level set too high.
Adjust float according to Float
Replacement Procedure.
Dirt under fuel inlet needle.
Remove needle; clean needle and
seat and blow with compressed air.
Bowl vents plugged.
Blow out with compressed air.
Carburetor bowl gasket leaks.
Replace gasket.
4. Make sure air cleaner base and carburetor are
securely fastened to engine using gaskets in good
condition.
5. Make sure air cleaner element (including precleaner
if equipped) is clean and all air cleaner components
are fastened securely.
6. Make sure ignition system, governor system,
exhaust system, and throttle and choke controls are
operating properly.
