Right on Badger !Sums it up !The ethanol or no-ethanol gas is crap. Plain and simple. Treatment is always necessary? Even for non-ethanol fuel. How much fuel are you talking about? My advice, since you asked, would be to dispose of the old fuel and get fresh fuel for the season and treat that new fuel. To me, you need to ask yourself, is it work the price of a tank of fuel to get stuck out on the water?
You may be able to reuse the fuel in your vehicle added in smaller amounts.
A post of mine from another thread.
I don't have a Yamaha on my boat so maybe I'm not qualified to chime in on this but I am very picky when it comes to my mechanical things. Drilled into me when I was young. I'm not sure people realize that gasoline, ethanol free or not, has a very short shelf life these days. It can be as little as 15 days until it starts to breakdown. Before ethanol gasoline had a shelf life of 9 - 18 months but it seemed to last even longer. Years ago I remember starting things that sat for a couple years and would run fine.
I did my research until I felt comfortable with what I believe I should do. My engine sat for quite a bit of time before I bought it. Last year was "iffy" for the motor running well. I was afraid I might need new carbs. I spent some time this year before putting it in the water and it is (fingers crossed) running really, really well. Like it should. So with all that said I believe that using both is cheap insurance. It seems to me that the Ring Free is more for preventing carbon build up and the Sta-Bil is more for stabilizing the cheap (but expensive) gas. Just my 2 cents.
I preach this at home too with any fellow boaters that care to listen. I hate this "new" gas.