Each time we go out and fill the ballast up and begin to surf the check engine light goes on. Per a thread I read on here I replaced both O2 sensors. I am now trying to burn through the remaining gas in the tank running laps around our lake, just in case it is a gas issue. No check engine light when I am running 30 mph to burn gas. I am now going to fill the tank with 91 non-ethanol gas. Again, the orange check engine only comes on when the motor is under high stress, surfing for example. Any other thoughts on what it could be? I do not have the correct tools or knowledge to check the fuel line pressure.