We just bought a pair of 2000 yamaha gp1200r's. All stock, and runs on premix. Everything was going great until day 2 on vacation, we took it out for a ride, came back to switch riders and we had no power. Battery was dead and HOT. Well this morning after charging it, we went to put the battery back in and when we touch the terminals to the battery, the waverunner tried cranking over. We took apart the start button and everything looked clear and fine. Safety key was not in and the start button was not pressed down. So my question is what could it be?