Found out the hard way this weekend that my generator battery was dead. I changed out the group 27 deep cycle for a sealed add no water type starting battery that has a slightly higher rating than the group 27 battery. After an over nite charge I tried starting the generator but when I hit the start button I get a loud clunk and nothing else. Anyone had this happen ? I'm hoping it's a easy fix, the generator started and ran fine when we left the marina but two days later it won't turn over.