MGM 16018 Cutting out at 1/2 to 3/4 throttle

G'Day I have just finnidhed installing a NEU 1515/1D motor in my Jato.
The Controler is a MGM 16018.

I am not sure if I am missing something, but when I reach about 1/2 to 3/4 throttle it just cuts the motor off.

Everthing is running nice and cool so there are no over heating problems.

I am only running 3s Lipo 5000mah batteries. Yet to try it out with 8000mah.

Doese anyone have any ideas on what is happening and how to go about getting full throttle out of it?

Any information is appreciated.