Air Cleaner Housing: Description and Operation

Fig. 67 Heated Intake Air System:

The air cleaner is of the conventional paper element carburetor mounted type. The air cleaner includes a valve to regulate the mixture of warm and cold air entering the carburetor. The air valve is operated by a vacuum motor controlled by a bi-metal thermosensor. These components comprise a heated intake air system (TAC) which allows the carburetor to be calibrated leaner than would ordinarily be possible to reduce CO and HC emissions during warm-up, improve cold engine driveability, and reduce carburetor icing.
The functions of the components contained on the air cleaner are as emission control devices, therefore for any further description of, or testing of these components refer to EMISSION CONTROLS under HEATED INTAKE AIR (TAC).