regarding "old" fuel.........
Winters are long with wide temperature swings in RI. Those conditions are terrible for storing fuel at marinas. It's a known fact marinas do not top off in-ground fuel tanks in the fall and they certainly do not treat fuel!
With that said, do you realize marinas put out bids for fuel? Come December if the fuel is low $ they will top off tanks or maybe come Memorial day they will top them off.
for the record....... the only gas available at marinas is 10% ethanol.