Insufficient data. I would guess you are using a 3s pack? If so my first guess is that with a 3100kV motor you could be pulling about 30 amps. If so you need to reduce prop load.
If you are now to electrics I would think you don't have a power meter.
Check out eCalc online.. put in the right motor and battery data and it will give you a good idea what is going on.
And of course make sure the controller gets enough cooling air.