If it’s ethanol free just the regular Yamaha additive you should be using all the time. That’s all I’ve ever used and have never had fuel issues other than letting ethanol gas sit too long in my carbs. The rest are snake oil in my opinion.
I could be wrong, but I would think pumping out that old gas would be a good idea if its been sitting that long. That being said, I have run Stabil for almost a decade with zero issues on Yamaha and Evinrude 2 strokes, and tohatsu 4 strokes.