[nl12]

I would not think it to be an amp draw issue since he said the motor cuts out unloaded as well, it couldnt be pulling that many amps unloaded. I would try reprograming the controler. Maybe you have a different kv motor than you think and it is hitting the 42000, maybe lehner mismarked the motor, stranger things have happened. Try the motor with a different controler like a 9920 unloaded and see if it does the same thing, if it does then something is definately wrong with the motor, if it works fine--maybe its your controler, maybe it is the mismarked kv issue. I dont know how to test the kv of a motor if anyone does that could help eliminate one potential problem.