There was an article that I read a while ago and it was from Hawaii and boaters were experiencing a great deal of problems when using Ethanol based fuel. Ethanol was mandated to be used in all fuels on the Islands and the problems were mainly with Marine Engines and other small engines that would be stored for periods.
It breaks down some gaskets and fuel lines on older boats causing motors to clog with debris and at times damaging the engines. The only way I would run it is if you were going to run it completely out after use and use it when Non-Ethanol fuel was unavailable.
I don't think this is the exact article but they do have a lot of problems over their when using E10.