Engine Service Manual

Fuel System
36 32 690 03 Rev. IKohlerEngines.com
Troubleshooting Smart-Choke
™
Related Causes
Condition Possible Cause Conclusion
Engine starts hard, runs rough, or
stalls at idle speed.
Choke not closing. Check choke lever/linkage to ensure
choke is operating properly.
Check that bimetallic spring actuates
freely.
Engine runs rich (indicated by black,
sooty exhaust smoke, misfi ring, loss
of speed and power, governor
hunting, or excessive throttle
opening).
Choke partially closed during
operation.
Check choke lever/linkage to ensure
choke is operating properly.
Check that air vane is operating
freely.
Choke not opening. Check choke lever/linkage to ensure
choke is operating properly.
Check that air vane is operating
freely.
Check choke thermostat bracket
assembly.
Smart-Choke
™
System Troubleshooting
Oil Pressure Switch
B
A
A Power In Terminal
B Power Out Terminal
These procedures are to be performed on a cold engine.
NOTE: Bimetallic spring assembly is pre-set at factory.
DO NOT attempt to adjust/change its settings.
NOTE: Do not remove or loosen thermostat screws.
Position is set at factory.
NOTE: Thermostat temperature must be at room
temperature before testing.
1. Remove air cleaner cover, and air cleaner from air
cleaner base.
2. Choke plate should be fully closed when engine is
cold.
3. There should be light spring tension holding choke
closed.
4. There should not be any binding when choke shaft
assembly is rotated, which could cause choke to
remain partially open.
5. Remove blower housing.
6. Check choke linkage and air vane defl ector
assembly for binding or debris build up. Gently
actuate linkage and observe that choke plate has full
range of movement (open and close).
7. Unplug red wire with black tracer power lead of
bimetallic spring assembly. Measure heat circuit
resistance of choke thermostat assembly, with a volt
ohm meter at room temperature (68°F/20°C).
8. Attach one wire of meter to red wire w/yellow tracer
terminal of assembly, and other wire to ground of
bracket or to ground strip of assembly body.
Thermostat resistance should read 15 ohms (+/- 10
ohms). If assembly is warm, allow unit to cool to
room temperature (68°F/20°C) for accurate testing.
If an infi nite (open) reading is found, replace
bimetallic spring choke bracket assembly. Air vane
linkage will not open choke plate fully when cold and
will not close choke plate fully when engine is warm.
9. Reinstall blower housing.
10. Start engine. Upon start up, choke plate should be
1/3 closed. Choke plate should gradually change to
full open position after 2 to 2-1/2 minutes of running.
This action is performed by bimetallic spring
assembly being heated. If choke plate fails to open,
recheck linkage for binding.