Carburetor; Troubleshooting -- Carburetor Related Causes; Troubleshooting Checklist - Kohler CH940-CH1000 Service Manual

Carburetor

Explosive Fuel can cause fi res and severe
burns.
Do not fi ll fuel tank while engine is hot or
running.
Gasoline is extremely fl ammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well ventilated, unoccupied buildings,
away from sparks or fl ames. Spilled fuel could ignite
if it comes in contact with hot parts or sparks from
ignition. Never use gasoline as a cleaning agent.
Engines in this series are equipped with a Keihin BK
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, bowl
drain and a fuel shutdown solenoid.

Troubleshooting -- Carburetor Related Causes

Condition
1. Engine starts hard, runs roughly, or stalls at idle
speed.
2. Engine runs rich (indicated by black, sooty exhaust
smoke, misfi ring, loss of speed and power, governor
hunting, or excessive throttle opening).
3. Engine runs lean (indicated by misfi ring, loss of
speed and power, governor hunting, or excessive
throttle opening).
4. Fuel leaks from carburetor.
62 690 01 Rev. C
WARNING
KohlerEngines.com
Fuel System and Governor

Troubleshooting Checklist

When engine starts hard, runs roughly, or stalls at low
idle speed, check following areas before adjusting or
disassembling carburetor.
● Make sure fuel tank is fi lled with clean, fresh
gasoline.
● Make sure fuel tank cap vent is not blocked and that
it is operating properly.
● 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.
● Make sure air cleaner base and carburetor are
securely fastened to engine using gaskets in good
condition.
● Make sure air cleaner element (including precleaner
if equipped) is clean and all air cleaner components
are fastened securely.
● Make sure ignition system, governor system, exhaust
system, and throttle and choke controls are operating
properly.
Probable Cause/Probable Remedy
1. Low idle fuel mixture (some models)/speed
improperly adjusted. Adjust low idle speed tab, then
adjust low idle fuel needle.
2 a. Clogged air cleaner. Clean or replace.
b. Choke partially closed during operation. Check
choke lever/linkage to ensure choke is operating
properly.
c. Low idle fuel mixture is improperly adjusted.
Adjust low idle fuel needle (some models).
d. Float level is set too high. Adjust fl oat according
to Float Replacement Procedure.
e. Dirt under fuel inlet needle. Remove needle;
clean needle and seat and blow with compressed
air.
f. 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.
g. Leaky, cracked or damaged fl oat. Submerge fl oat
to check for leaks.
3 a. Low idle fuel mixture is improperly adjusted. See
Remedy 2c.
b. Float level is set too low. See rememdy 2d.
c. 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.
4 a. Float level set too high. See Remedy 2d.
b. Dirt under fuel inlet needle. See Remedy 2e.
c. Bowl vents plugged. Blow out with compressed
air.
d. Carburetor bowl gasket leaks. Replace gasket.
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