use premium fuel (all fuel, no ethanol).
even stabil will only help for up to 6 months. ethanol does not have the required carbon back bone for stability and starts to break down immediatly upon dispensing. plus in a marine environment, the ethanol absorbs water from the air, then as it sits the ethanol starts breaking down and the water separates out causing corrosion.
I myself simply fill the tank in November when I put the boat away, and pull it out in March.
