On Sun, 5 Mar 2006, RST Engineering wrote:

However, when Ernie found out that California fuel contained about 5%
ethanol, he considered that the rubber bladder fuel tanks and the
neoprene carb needle probably wouldn't be overjoyed sitting all winter
in an ethanol bath and hasn't used it since.

Did Ernie ever take a look at those & other parts to see if they were
actually affected by the ethanol?

On a related note, I'd be very interested in hearing about experiences or
knowledgeable opinions on using ethanol in an IO-360-A1A. In particular,
I'd like to know if there's anything in the fuel injection system that
would be negatively affected by ethanol, and what octane I need to stay
above to avoid any chance of detonation (8.7:1 compression). It's in an
experimental airplane so there's no concerns about legality.

-Dan