MM input voltage.

I used to run 14 cells on my maxx all day long and with a fan temps were good. Then i finally smoked it(back flip and throttling it sent amps threw the roof) is what im thinking. So i sent it in and they game me a brand new one. and now it wont run on 14 cells. It "arms" but it wont go. The new ones have somesort of overvolatage protection. It runs like a champ on 12 cells. I read somewere on here that there was a way around the protection, by turning of the lvc, but that didnt work for me. Im thinking about letting the 14 cell pack rest for an hour, and then trying again.
Or just maybe one day my stupid mmm will come :(