Idle Compensator
The Idle Compensator is generally used on vehicles with air conditioning. When a vehicle comes to a stop and the engine is hot, the carburetor tends to richen up and even percolate (boil). The compensator has a bimetal piece of metal that when the temperature gets hot, the bimetal curls up and causes the idle compensator to open. This allows extra air into the intake, below the throttle valve.
