Since this seems to be going the wrong way it might be good to double check your set up. You don't just happen to have a cable or cable driving your throttle? That will act as an antenna and bring the RFI back to the servo and down line to your RX. The other thing to watch out for is keeping your switch harness, battery pack, and all radio system stuff at least 8 inches from the engine.

I am sure that what C&H told you is applicable to electronic ignitions where capacitances are critical in the design of the circuitry needed to generate a spark and the antenna capacitance represented by the spark line probably should not be tampered with by the uneducated <G>. However, I don't think they are that critical in a magneto system, which is what Ken indicates. As for the Fuji, the only experiences I have had with their systems were bad. Their "ATM" modules seem to have a very short life from what I have seen. Something measured in minutes rather than hours...