If you have a metal throttle arm, you must use something plastic for a connector to the throttle arm to keep from producing RF noise.
Or you could use a plastic control rod
http://www3.towerhobbies.com/cgi-bin...&I=LXK091&P=ML
http://www3.towerhobbies.com/cgi-bin...&I=LXFV42&P=SM