In the past winter seasons I top off my 40 gl tank w/ well mixed green stable. After 2 months or so I in times past would use an old ford external fuel pump to recirculate my gas in 40 gal tanks for outboard to prevent posibility of ETH phase separation.
THIS TIME- 4 months passed Before circulating it I pumped 1-gal. into jug. I noticed it was slightly dark corn yellow. I sniffed away from jug barelly smelled like gas. Put nose next to jug it had weak gas smell. Put an ounce or so of gas in old galvanized bait bucket, threw a lit paper towel into it and it put out a much weaker flame than expected. Top of flame at 1st flamed up a littler higher than top of bucket. Gas in my experience lit gas usually gives a violent poof and flame up.
I guess I won't know for sure until I buy an ethanol detector from I guess an auto parts. I am not going to circulate this 40 gal of gas till further research & testing .
I always thought toping the tank before winter with well circulated green stabil would prevent dreaded phase separation.
I read w/ phase separation- ethanol and water will mix sink to bottom of tank and it will be sucked into cylinder.
I have a friend that doesn't pay attention to the ethanol issue & blew his 2-stroke older 150 ob after it sat for a few yrs and another friends 2-stroke old that runs like junk w/ old gas. I'm sure he is headed for trouble too.

Drain it and start again

Phase seperation can still occur with the tank full. It doesn't take much moisture/condensation to make the ethanol drop out of the fuel. Unfortunately, the fuel looses points of octane when this happens.

If draining is not an option, we sell a product that puts the water back into suspension in the fuel and can be expelled while running. It doesn't hurt the performance or have any ill effects on the motor. It's highly recommended to add fresh fuel of a higher octane before running at a higher or suspended rpms.

My boat just started (i hope so) showing effects of this. It is dying when i take off and get up to speed. not every time but i let my fuel set during the winter. I usually fish during the winter, but just never found the time. When i went the first time this year, two weeks ago i put in about 15 gallons of premium. Now it is starting to die after 30 to 45 seconds of running.It starts back up fine and will run for a little while. Ive also heard the methanol will corrode your fuel lines. Anyone else having this problem. To the best of my memory i may have had 5 to 7 gallons left in the tank from last fall.