keep using the non ethanol fuel. that is the number one best thing you can do to insure you wont have the gum and varnish that ethanol causes....
but, for a fact, seafoam disolves the gum and varnish caused by ethanol.
any one skeptical, heres how to prove it to yourself.... take any old gas container that has had ethanol gas in it for a season or two and you will see the black sludge in the bottom of it... thats the gum/varnish that has developed. pour of most of the old gas out but leave the sludge in there, then try any chemical, solvent or thinner you can think of to try and dissolve the black mass.... it wont.
and as it does not dissolve and is still a black mass, dump in a couple ounces of seafoam... within two hours you will see the mass is dissolved and the liquid will be black as it has dissolved into a solution of seafoam, gas and sludge..
seafoam in an engine will dissolve any residual gum and varnish within the fuel system... it can actually braek a large mass free and allow it to plug the carb, but given time, it will fully dissolve the mass and allow it to pass thru so that you have a clean system...
as for an additive that does not work, the red stabil comes to mind. it does not stabilize ethanol fuel, use the blue stabil, it is the marine formula and will work on any type of fuel... it is also more concentrated so you use less of it.
and even though most of us use the ethanol free fuel in which the red stabil does work, that is not a good reason to use the red stuff when the blue stuff is so much better.
in all my small engines which is considerable in number (everything except our cars) I use ethanol free fuel, and I mix it with the proper amount of both seafoam and blue stabil, and never in the past 8-10 have I had to have anything serviced due to a fuel problem.... and I very seldom drain the fuels or run them dry when they are put away for the season.
the seafoam works and the blue stabil works... the ingredients of both may be common, but the formulations as purchased under these brand names have instructions on how to use and how much to add to the fuel... and more isnt always better.