I just purchased a 2004 Mercury engine. What is the oil/gas mix? I used the boat about 5 or 6 times and recently the engine sputtered then quit. I couldn't restart it. When I got it home and checked it the cylinders were locked up. I sprayed it with a lubricant and now it seems fine and starts right up. Does anyone have any idea what could have caused the problem. I thought that maybe the gas/oil mixture could have been wrong. Thanks for any help!