Cobra PR-650 w/ headset interference

I have several Cobra PR-650 radios. I have one outfitted with a full face helmet speaker, mic, ptt setup. I race karts, with small engines that are known for a lot of electronic interference.

My problem is, as long as the motor is not running I can transmit and receive with no problem and the range is more than I had hoped for. BUT, when I fire the engine up I can not transmit or receive. No static, no “click” when the button is pushed, nothing. It’s almost like something is completely blocking the transmission and receiving when the motor is running.

Last race day I played around with placement of the radio on the kart and if I get it just in the right place and got it to where once in a while I could receive in the kart, but just as I thought we had it so I could at least receive, it went out again.

I really did not want to go the $2k plus radio setup route if possible… but what can I do??