Something represented as “ethanol treatment” might cause a false sense of security. Be aware that adding a fuel treatment isn’t going to change ethanol from what it is. Just know that when combined with water, ethyl alcohol has corrosive potential in a fuel system. To answer your question, Sea Foam’s petroleum ingredients will add protective lubricity to fuel system parts. Another key is to manage your fuel in favor of frequent replenishment. Also keep in mind that your Optimax is built to handle E10 (10% ethyl alcohol). No matter what gas you’re running in your Mercury, remember that Sea Foam is always working to clean and lubricate your fuel system.