My good friend had a boat with twin 200 yamahas and he swore by ethanol free gas. My boat actually sat this past fall for a month without being run, the longest my boat has ever gone without hitting the water. It ran so bad for the first 15 minutes that I thought it was something more serious. It was just the ethanol gas. Since then I will only put ethanol free gas in it. It's more expensive and out of my way but I'm willing to sacrifice just to get it. I've cleaned the rust out of the carburetors on my lawn mower, pressure washer and everything everything else that sits any amount of time. Adding ethanol was the worst idea they've ever had for gas.