better to run no ethonal gass ?

I prefer to avoid ethanol gasoline because the alcohol simply has less energy than pure gasoline. I get 10% better mileage with pure gasoline. Some older engines and lawn mowers have problems with ethanol and I think it's because it attracts moisture. Unfortunately I have to buy Premium to avoid the ethanol content. I think the whole idea of ethanol gas was to make billionaires out of the corn farmers out West. I used to work a Quaker State refinery (1969) and all our gasoline came out of the ground.

Real gas is always best if you can get it.

E10 is fine, but don't try E85.