Cavandish,

I had a similar problem with my DA-50 not long ago after a deadstick. The engine rpms would go way up and down. Noticed that the throttle servo was moving up and down and the optical kill(smartfly) was blinking on and off. Tried a 42-Percent optokill and it did the same thing. It ended up being the spark plug cap wire was pulled back slightly sending interference to the servo and kill switch. I took the cap apart and pushed the wire back in and all is well again.

Eddie