Kohler KT726 - Page 37

Fuel System
3732 690 03 Rev. N
KohlerEngines.com
Smart-Choke
™
An air vane deector assembly that operates by air from cooling fan opens choke partially when engine is running.
When engine is cold, a spring on air vane deector assembly, in conjunction with a bimetallic spring, holds choke
closed for starting. A bimetallic spring reacts to heat generated by electrical resistance as engine is running and opens
choke plate position. When engine is warm, bimetallic spring holds choke completely open, while engine is running.
Choke will be 2/3 closed when warm and not running. These two elements work together to operate a smooth choke
system that facilitates easy reliable starting.
As of this revision, there is an original design and an updated design. Identify design on engine being serviced and
follow those details to diagnose and troubleshoot.
Original Design Smart-Choke
™
Original design had a 3-terminal oil pressure switch as
part of system. Several other components in original
design have had improvements.
Thermostat
Thermostat Identication
A Adjustable Thermostat
B Dual Position Thermostat
First thermostat was an adjustable thermostat that needs
to be reset if mounting screws are loosened or removed.
This was then replaced by a dual position thermostat
with mounting holes for CDI ignition position or MDI
ignition position.
Air Vane
Air Vane Identication
A Early Design Air Vane
B Later Design Air Vane
Early design air vane was used with an adjustable
thermostat or a dual position thermostat mounted using
proper holes for ignition system on engine (plain holes
for CDI or M holes for MDI).
Later design air vane requires a dual position thermostat
ALWAYS mounted using plain holes.
Deector Support Tab (if equipped)
Some early production engines were built with a
deector support tab. This separate part was eliminated
and molded onto intake manifold.
Updated Design Smart-Choke
™
Updated design removed oil pressure switch from this
system and also replaced a 3-terminal oil pressure
switch with either a 1-terminal oil pressure switch (for
user notication of low oil) or a plug. Wiring harness
also changed for proper connection to a 1-terminal oil
pressure switch and a 5 amp fuse was added in power
supply line to thermostat.
B
A
B
A