I used to have to add HEET to our gas tanks in winter to prevent water in the fuel from freezing. I haven't had to do that since the late 80s using E10. Why? The alcohol in E10 prevents the water from freezing. Same as HEET.
So many people keep bringing up the phase separation issue. It's a non-issue if you follow the manufacturer's recommendations about fuel storage.
From here:
People who own boats, lawnmowers and other seasonal equipment have debated for years, sometimes heatedly, about the engine-impacts of ethanol-blended gasoline. the dispute has centered on the issue of water uptake and phase separation in small and off-road e
www.agri-pulse.com
(bold me)
The research found that the petroleum components of ethanol-blended gasoline become degraded and unfit for use in an engine long before the ethanol portion takes up enough water to cause phase separation in the fuel tank.
“In a small engine fuel tank in a constantly high-temperature, high-humidity environment, it takes three months or longer for E10 and other ethanol blends to take up enough water for phase separation,” says NREL. “This confirms the statement by
Mercury Marine that
water uptake in E10 blends ‘does not happen at a level or rate that is relevant.’”
“Every manufacturer of small and off-road engines has approved the use of E10 in their equipment for many years,” said Bob Dinneen, president of the
Renewable Fuels Association (RFA), who requested the study.
"If owners of this equipment simply follow the manufacturers’ recommendations for fuel, maintenance and winterization, they won’t have any issues at all. But, as this study shows,
letting gasoline sit in your tank for extended periods of time is likely to cause some issues – irrespective of whether the gasoline contains ethanol or not.”
