Here in Ontario Our regular 87 Octane fuel uses 10% Ethanol. I purchased a 1989 Mercury 25 hp 2 stroke outboard this past spring and used it sparingly throughout the summer on my 14 ft fishing boat. I used regular 87 octane with ethanol with the appropriate 50:1 oil mix assuming that's all I needed to use according to the Mercury website. However, when I purchased a new lawnmower last spring and used the same 87 octane grade in it during the summer, I experienced carb problems and had a warranty claim on my hands. The small engine company handling the claim stressed that premium fuel should only be used because it has no ethanol in it and said that that same thing applies to any small engine including outboards because the ethanol can very quickly ruin carb jets etc. I would be interested to here other people's opinions on this. I look forward to your thoughts.