I agree with the recommendations to change the throttle linkage to plastic and crop all the extra wire off the kill switch or even do away with the kill switch and adjust the throttle to kill the motor. Most whacker conversions using mag will not fire unless spun up with an electric starter so the kill switch isn't needed when choking. If your motor by chance will fire by hand propping, then keep the kill switch for safety.

One other thing that hasn't been mentioned yet that I've experienced once is to keep the antenna wire away from any pull/pull wire rudder linkages. In that instance, the interference showed up while range checking and had the range reduced to an unacceptable level and simply re-routing the antenna wire to the top of the vertical stab reestablished a good range check.