Let’s assume the adventure you have been planning does not include the episode where your boat is bobbing dead in the water while you troubleshoot a tank full of crappy gas. Here’s how to avoid that scenario. Ethanol remains the leading culprit of fuel issues in gasoline-powered marine engines — ethanol is corrosive, it’s a solvent, and it absorbs moisture. In a boat it’s nothing but trouble. The obvious action is to not fuel your boat with an ethanol-blend gas. When that’s not an option, you need an ethanol defense strategy, like these tips we’ve gleaned from Yamaha Marine.