Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Idle/Altitude Compensator (Non Comp. Controlled): Description and Operation
Hot Idle Compensator
Fig. 17 Hot idle compensator
The hot idle compensator, Fig. 17, used on some vehicles, 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.