Thermostatic Air Cleaner: Description
All models use a system for preheating air entering carburetor. A vacuum motor, part of the air cleaner, maintains the air temperature at a point where the carburetor can be calibrated much leaner to reduce hydrocarbon (HC) emissions while also improving warm-up operations and reducing carburetor icing.
System consists of an air cleaner assembly, integral air control door, vacuum control temperature sensor, vacuum motor, heat shroud (on exhaust manifold) with connecting pipe and vacuum hoses. Some models use additional controls, such as vacuum traps and cold weather modulators.
All Light Duty Emission vehicles use preheated air to warm carburetor.