Yamaha Outboards Fuel Recommendations

Yamaha, makers of marine outboard engines, maintains a section on their website for frequently asked questions concerning the use of ethanol blended gasoline.

Are Yamaha engines compatible with E10 fuel?

All current models as well as most engines built since the late 1980’s have been designed with fuel system components that are tolerant to fresh fuel containing ethanol up to 10% (E10). Outboard fuel systems can still be affected by: water, dissolved gum, varnish, corrosion particles, and dissolved resins that E10 fuel has cleaned from the distribution system and your boat’s fuel tanks.

Source : Yamaha Outboard FAQs