So I just bought an e-revo from a guy down on his luck, he just installed tekin rx8 system has many upgrades. He said servos needed replaced so I did, the wheels turn right but that is it and one of then gets wicked hot even when its not connect to linkage. I should note that its my first rc and when I first installed the servos I didn't zero them on account of not knowing. Can anyone tell me what I need to do? Much thanks!