Any ethanol in boat or aircraft fuel is death; I've talked to people who have had to rip out fuel tanks and replace them with stainless steel for their watercraft. As I said in an earlier post, chemicals is chemicals, sometimes they are compatible and sometimes they ain't....
Disclosure: I formerly worked for an ethanol manufacturer, but left on less than amicable terms, I am actually neutral/against ethanol(I prefer electric cars), but as an engineer I hate to see misinformation spread.
Guys running ethanol in airplanes:
Aviation grade E85 -It's great because no longer will water seperate out and freeze in the lines. I find it ironic guys are opposed to ethanol but seem to have no problem with LEAD in airplanes.
Energy content: Ethanol takes around 30-40,000 btu's of energy to make one gallon, which yields 76,000BTU's if memory serves. Most of the energy goes to drying the byproduct which is used as cattle feed(cattle aren't starving). The guys quoting 1.5 gallons to make one gallon are using numbers from the 80's. Technology has improved since then, or else your cell-phone would be a backpack.
It's not perfect, but neither is gasoline. You can get ~600+ gallons of Ethanol plus 60 gallons of corn oil per acre compared to 60-80 gal per acre of oil from soybeans for biodiesel.
A gallon of E10 could withstand 3.8 teaspoons of water before phase separating.
http://www.epa.gov/oms/regs/fuels/rfg/waterphs.pdf On the bright side, you never have to buy "Heet" gas line dryer again, ethanol has eliminated that need. For those that did use Heet, the methanol in it is far more corrosive than ethanol, which is only corrosive to certain metals in certain conditions.
I could go on for days, but as a previous poster said, carb problems were a problem in the 80's, it is not a "new" phenomenon
As to the original poster's question, there is no way to "neutralize" it, though you can separate it out with an overabundance of water. Most additives are snake-oil, preying on a gullible populace. If you search around, there are many organizations offering to pay for engine damage caused by ethanol in cars, and to my knowledge, none have had to.