If most any of the merc, evinrude and other major brand motor owners had regularly performed and competed their proper recommended maintenance on their older motors, then E-10 will not harm their fuel lines, seals or other fuel components..... Fuel lines and 100% of the replacement parts have now been ethanol compliant for many, many years...since the 90's at least.

Those blaming ethanol for their fuel system related engine damages likely already had very old fuel components way over-due for replacement and never did their required maintenance on their motors.

Now, if your motor is old enough it was designed for leaded gas, non-ethanol fuel alone is not going to help you.