I have two tanks, a 3 gallon and a 15 gallon, that I use for my 1998 50 Johnson two stroke outboard.
Pure gas in the 3 gallon.
10% ethanol in the 15 gallon.
At the end of every cruise I run on the three gallon for about five minutes. I can't run this carb empty as it is an oil/gas mixing carb/fuel pump.
At the start up of every cruise I start up on the 15 gallon, switching fuel lines over from the three gallon.
Works great.
My log splitter has a 1990 18 hp Briggs I. C. engine.
Has a ten gallon tank and I use 10% ethanol.
At the end of every splitting session I cut off the fuel supply and let it run until it dies.
I rebuilt the carb about 8 years ago.
Works great.
My rule of thumb for 10% ethanol fuel is never to leave it sitting in a carb. And never let the fuel get more than a month or two old.
I use pure gas, 90 octane, in all of my chainsaws with oil mixed 40/1. If I believe a chainsaw is going to sit for more than a few months I start the saw and while it is running I pour the fuel out of the tank into my chainsaw fuel can, and then run it until it dies.
Has worked great for years.