A choke servo controlled by a switch on the transmitter is my best answer, six out of my seven gas engines are rear carb so to me a choke servo is necessary. I kill my engine after a flight by closing the choke which in turn primes the engine for the next start up! The fuji is the only engine I have without a choke servo because it is side carb and maybe an ignition kill switch would be a good idea but never have had a problem getting it to shut off!