Handy,

You have several options depending on your radio and what you have installed. On my P-51 I use an MPI combination on-off/charge/battery indicator switch; a choke on a servo; and throttle cut-off programmed into my radio. This means I can shut it down two ways in flight: with the throttle cut-off or by closing the choke. My primary ignition switch is manual only. I believe some have put their primary ignition switch on a servo, but I'm not big on that option.