I have a home brew air compressor which uses
an electric motor. It uses a pressure switch
to stop the motor when the tank reaches full pressure.

I'd like to put a small gas motor on the compressor
because the electric motor usually gets hot and
shuts down.

How are gas motor air compressors controlled?

You cannot start and stop the gas motor, so, is there
some sort of dump valve that opens when the tank
reaches pressure?

I want to use a gas engine, but I don't want to rely
on the overpressure valve for normal ops.

Thanks.