WOW!

Setting up gassers is fairly simple if you follow several simple rules.

1. Keep everything associated with the radio separated from everything associated with the engine by at least 8 to 12 inches. The 14 you were quoted is gold plating <imnsho>. That means the switch, the battery pack, and the ignition module all need to be 8 to 12 inches away from the receiver and any servos.

2. Always use a golden rod to connect the throttle linkage to the throttle servo that is back by the radio gear in line with Rule #1.

3. Always use a resistor plug.

4. Never allow metal to touch the engine or its mounts because it WILL create RFI you don't want.

I see by your pictures and text that you violated at least 3 of those rules and that is probably why you have a problem. I think if you correct those, your problems will go away. I very strongly suspect the solid throttle rod is playing antenna and transmitting RFI splatter to the throttle servo lead which is carrying it back to the receiver. Even in 2.4GHz systems, the IF strip inside can be swamped.



Now having said all that, a friend addressed this problem back in the 72mHz days by building a transmitter that plugs into the throttle slot on the receiver and a receiver that is mounted by the engine with the throttle servo and a switch that puts that servo on the ignition battery pack and turns the ignition system and throttle servo off. The 2 units are linked by optical cable so there is no electrical connection. I paid him $45 each for 10 and still have 4 left unused. I do use the other 3 he made me with my 2.4GHz radios because *I* am a coward and always take the safer way out. The other 3 were very special and had smoke and throttle servo controls at the engine.