I recently purchased my first actual gasser that I plan on keeping. I have successfully started the motor and it has great power and idles at a very low speed. The issue gets to be when I range check. If I get more than 20 -30 feet away the throttle jumps to 1/2 to full throttle until I move back towards the plane. There is no ground on the ignition or spark plug cap. I ran a plastic throttle cable thinking this could be the issue and also increased the distance between the CDI and RX.

The motor came with a Torch L7RTC.

Should there be a ground hooked up to the plug / cap? Should I try a different plug? Need to get it figured out before I maiden this biplane!