What does a Heater Assy do on a Carburetor?

Answer 1

Most automobiles built during the 1960s up to the Fuel injection era had a carburetor heat system, most times two.

The goals were twofold:

1st the fuel and air mixture would burn better and cleaner in a cold engine if the mixture was warmed. So for the first few minutes of start up the intake manifold is commonly heated by exhaust gasses.

2nd the intake air will freeze inside the Carburetor during humid days and ambient air temperatures 70 f and below. Most air cleaners were equipped with a heater plumbed to the exhaust manifold set too automatically to maintain 80 degree or warmer temperatures. Most light aircraft are equipped with a similar manually operated system