I double checked the + and - on the motor and that is correct. I don't think it got to hot when I put the new motor in, it only had heat long enough to melt the solder. I did test both the motors and they seem to be fine. I'm going to try more adjustments on the 3 in 1 board. It may just be that I haven't adjusted it enough to get the surging out of the tail motor. This is a lot more complicated than the old RC Cars I had in the past, but more fun to learn