Kill wires can cause interference. I would run a setup with a plastic pushrod from a rearward mounted servo to a kill switch, and keep the kill switch near the engine with short wires. Another way some people run a radio operated kill setup is with a plastic pushrod setup to the choke.

Also, a friend of mine had a problem with radio interference on a Homey 25cc with the original magneto. We shielded the plug wire and kill switch wires and the glitching went away. For the plug wire we used the shielding off of a piece of T.V. coax cable. For the kill switch wires I had some aircraft shielded wire. Radio Shack might carry it....

Note: Any shielding used gets grounded on only one end.

AV8TOR