Just retanked with the special summer gas mix that is used in major urban areas. Engine runs abit rougher now. Could just be a lousy tank of gas, but I was wondering if anyone else has noticed different outboard performance with the "summer mix" versus the standard gas that is offered during the rest of the year? I put in sta-bil and required gas/oil mix ratio. Engine is a Tohatsu 8. Also wonder if anyone has used 89 octane gas? I couldn't find anything in outboard manual stating not to use higher octane. Thanks