I have never used the optical kill switch, I just used the Hi/Lo/Kill throttle switch on my Futaba. I had my choke set up on a knob. Twist all the way and the choke was open and twist the other way and it was closed. That was on one of my rear induction engines and the only engine I used a choke servo on. My side induction engines i set up the choke with a push pull lever.