I am thinking that you have no comp chains and the weight of the ropes are having you come into the floor a little hot. This is not a fix, but it will let you know if that is the issue. See if it does the same thing with a few passengers in the car, or some added weight. I suspect that the Generator has brushes that are different than the ones the car was set up with. you may need to add a little series field. Or you may have a weak rectifier that feeds the motor field.