Pro ,
Got the SAME problem with my MDS motor .... it seems that the glw plug ignitor is NOT making a solid connection and when you flip , or electric start the motor , this causes just enough to create RF intereference .
What I do , is .... I set the carbs throttle to the postion I want , then turn OFF the RX for the boat , but leave the Tx on .... then , after she fires up , and I remove the glow ignitor , I then flip the on/off switch to on and all is fine .[8D]