Hot Idle Compensator

Fig. 14 Hot Idle Compensator:

The hot idle compensator, Fig. 14, cools the engine during hot idle operation. The compensator may be integral with the carburetor or mounted separately. When open, the compensator bleeds air into the manifold, leaning out the air/fuel mixture at idle. This increased air intake causes an increase in engine idle speed, resulting in cooling of the engine. Temperature rise on the bi-metal sensor lifts the normally closed valve and opens the air passage. A valve that does not fully close will cause high idle speed and excessive exhaust emission.