Nothing but Seafoam, end of the season, the tank, the fuel line and fuel lines under the cowl get drained along with either the carbs or FI system. Had a bad experience with Stabil one year, it turned into jello at the bottom of the gerry can, never used it since and I've never had to get any of the engine fuel systems worked on. No ethanol gas is also on my list. There are a handful of stations that still have regular no ethanol available.