The Choke Thermostat controls the idle of the vehicle by opening or closing the butterfly valve on the carburetor. When the engine is cold the thermostat will hold the valve closed which supplies a richer fuel mixture to the engine. As the engine warms a spring is expanded, opening the choke valve and allowing the necessary amount of air into the engine to keep it running.
Symptoms of a failing Choke Thermostat may include:
• Engine won’t start when cold
• Hesitation during warm-up
Automotive professionals often recommend replacing the Choke Thermostat whenever the carburetor is repaired.