Is This Normal?

[NeuRevo]

I have an E revo. Im runnin the neu 1515 1.5d, MM esc, and a Thunder power V2 25c 3850mah 4s lipo. I only get like 8 mins of run time. Is this normal. My temps are: motor 140, esc 100, batt 120, . And it coggs really bad when it at a dead stop till it starts to move then its fine. Im using the emax tranny with only 2nd gear in it.
I dont know if its my motor, esc, batt. Sumthin just dosent seam right. Im plannin on gettin a Quark and a 5s neu or Flight power Lipo. 5000mah or higher.
Thanks