Service letter SNL10-5 (yeah May, just slow here) states that after testing ethanol based fuels, they are not a alternative for 100LL fuel. In fact they say that operational safety may be compromised by the use of ethanol based fuels.
Now that ALL fuel in Washington State, as with many states, where do you guys get auto fuel for your STC approved aircraft that DOES NOT contain ethanol?
Cessna tests reveal the ethanol eats seals, gaskets, O-rings, increases internal wear on fuel pumps, corrodes ferrous compounds, forms salt deposits on screens, dissolves large quantities of water in the fuel system compromising fuel quantity indications.
If they don't like it, I don't like it. (E-10 in my car now
)