Actually, there is a simple way to control an electric choke, and it's exactly the way the car manufacturers do it. GM uses an oil pressure switch inline with the ignition voltage that interrupts the circuit to the choke in case the engine stalls. It's a 3-terminal switch that mounts just above the oil filter on small block V-8's. The two "normally open" terminals connect ignition voltage to the choke. The "normally closed" single terminal that grounds when the oil pressure goes away is the idiot light switch.
Ford electric chokes have a circuit that supplies AC voltage from the stator of the alternator. Anytime the alternator is not turning the voltage drops to zero, so choke heating stops. Since GM alternators do not have a stator terminal, it's best to use the oil pressure switch if you're using a GM alternator or a generator. The GM pressure switch also supplies voltage to the electric fuel pump on fuel injected engines, so it acts as a rollover switch, stopping pump operation in case the oil pump pickup isn't submerged in the oil pan.
Jerry
