Hot Idle Compensator

The compensator may be internal or external to the carburetor.

Temperature on the bimetal lifts the normally closed valve and opens the air passage.

Valves open at a higher temperature and close at a lower temperature. This opening and closing range is from -12 to -7°C (10-20°F). Nominal closing temperatures vary from 26-60°C (79-140°F).

A compensator with a valve that is not fully closing can cause high idle speed and a high emission CO.