Carburetor heater

A sheet metal jacket surrounding part of the engine exhaust system. Air from inside the engine nacelle or compartment flows between this jacket and the exhaust system component and picks up heat. The heated air is carried through a carburetor heater valve, and when carburetor air temperature is low, can be directed into the carburetor; otherwise it is dumped overboard. Air that flows through the carburetor air heater is not filtered.