yeah I run with nitros so thats what we run at Harewood and dont want to rock the boat and complain as lucky to be running with them at all
motor was hot but I was geared 1x pinion to high and had timing at 15 degrees which I think is default setting which sounds like it might be a bit to high
if you were only wanting a few more minutes I would say drop down to a 1700kv or similar and run lower timing/lower punch and keep off the loose stuff..easier said than done and you may be ok with youre present batteries.