Never it is hard on everything and I find its better to go to the airport and get 101 low lead cheaper in the long run. There is an article about the new CARB approved boat motors having premature failure due to the E85 fuel.
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Many Boat Owners, in recent years, have unknowingly used gas, blended with too high (unsafe) levels of ethanol alcohol. Running on gas with over 10 % alcohol in a marine engine will cause performance problems, and can also cause permanent damage to your marine motor.
Understanding the dangers and effects of alcohol gas, in addition to following all the necessary marine fuel system precautions, is now necessary to avoid any problems with E10 gasoline.
There has been much controversy, misinformation and confusion since the recent (2006) increased distribution of ethanol gasoline in the United States.
Recent marketing gimmicks by some fuel additive product companies, have confused boaters even more. These ads falsely claim their new products can "fix" or repair ethanol water-contaminated fuel...Phase-separated fuel can not be fixed, and it must be discarded.
Even high level, reputable government authorities, have recently published information that conflicts with previous articles and bulletins written years ago on ethanol.
Marine manufacturer fuel recommendations (eg. owners manuals), which in the past, often warned against using alcohol fuels, now document that up to 10 % ethanol in gas is acceptable.
As more people are using E10, the necessary precautions and dangers are becoming more apparent and better documented.
Boaters looking for instant answers and solutions will not find them- But, increased knowledge and following all the necessary precautions can spare you from most of the inconvenience and problems with alcohol gas.
http://www.evinrude-parts.com/boat_ethanol_danger_precaution.html
There is a lot more out there.