Mamba max esc on crt.5 issues....

[ren]

I have been having a similar problem lately. The mamba max in my .5 overheats after only 2-3 min of runtime with my 5000mah 3s packs. I have a 12T pinion on it. Could it be my Neu 1509-1Y (3600kv)? It works a little better with a bec, but in my communication with castle tech support they said it should work fine without the bec. My other cars are geared for about 30mph as well and in refrence top speed of the .5 seems way higher... Could it be the motor?... fried coil?