Brian, of course you are correct about ethanol attracting moisture. But regardless of what fuel we use, we will drain the fuel and clean the carb after every race day at the track. We don’t consider this a bother, just standard operating procedure. I never use fuel more than a day or two old anyway. You will never have any ethanol issues if you do this. Karting is so time consuming and expensive I don’t take any chances with the fuel or fuel system. This is less of a hassle than tracking down ethanol free fuel or race gas, especially when I like the tuning ease of pump gas with ethanol anyway. My leaf blower and weed whacker are a different story; they’d run better if I treated them like my karts instead of throwing them in the barn when I’m done with them.
And Mark, if you have easy access to both, why not test it? There is no magic bullet fuel. Any 91-93 octane gas, with ethanol or not, will eventually give you the same performance, it’s just a matter of how much tuning it takes to get there.