I have a 2010 Yamaha F115 begins to misfire after 5 min. Runs great for first five minutes then begins to misfire. If I bring it down to 4500 rpm or below it runs fine, anything over that it will begin to misfire. Fuel filters are fine, changed fuel in boat, plugs are fine, electric connections have all been checked. Yamaha specialist ran diagnostics and no code errors came up. They are stumped too. Any help would be great! Thermostat? Temp. sensor?
