I have recently acquired a used LRP V8.1 speed control. I'm running it in a T4 with SMC 5200 40C 7.4V Lipo and a Trinity 19T brushed motor. My son has run it in three races and two out of the three times it seemed to lose power until it stopped and would not go anymore. It appears to hurt the motor. The motors are about 170 degrees when this happens. I changed the ESC/motor and it runns great with the same gears with the motor temp of 130 degrees at the end of the race. I'm thinking to much power to the motor. I can adjust the max amps to the motor on the ESC but am looking for any suggestions to fix this or other people that have had this problem.

Thanks

I'm thinking it's the motor. Both motors you tried are getting the same voltage. A motor draws as much power (amps) as it needs. The battery and ESC don't decide this, the motor does. I think you have a brush issue.

It could be but I had it happen to two different freshly rebuilt motors. I've rebuilt the one that stopped yesterday and I'm going to try it with the V8.1 next weekend

Check for any binding in the drivetrain, as well.

Make sure that everything spins smoothly, and that your pinion mesh is good.

My point is that with the motor and lipo you listed you shouldn't have a problem like "too much power" (going to the motor) it just doesn't work that way.
I'm still on the motor idea, even 2 fresh motors can have brushes hang up etc.

I'll continue to monitor the situation. I changed the ESC and motor and he won the second heat and the main with no mechanical problems. I was wonder about the amp input because the ESC is supplied with current limiters and I only know enough about these thing to make me dangerous.

Thanks for the input drperry. The one thing I can do reasonably well is gear/drivetrain set up

nvmd

Doesn't hurt to ask - did you ever check the brushes and springs on the original 19T motor that was cutting out? When they get too short in my car, it runs fine for a bit until I stop at which point it doesn't start again...

Yeah when I pulled it apart the brushes were pretty much ruined so I cut the comm and installed new brushes. We'll see how it runs this weekend