Choke Thermostat Operation:
It operates by responding to the engine temperature or voltage signals and then positions the choke plate accordingly. The temperature sensitive spring contracts when cold and expands when hot. When the spring contracts, it closes the choke plate. On a cold engine, when it expands or uncoils, it opens the choke plate. Sometimes a choke stove pipe will be used to transmit warmth from the exhaust manifold to the choke thermostat. This unit is usually located either on the carburetor or in the intake manifold.