It's been at least 8-10 tanks.. It got better each time I filled it up. I put about 15 gallons in a 33 gallon tank at night. When I left in the morning it ran like it had water in it, so I put HEET in it. It seemed to help. It just got better with every fill up. Still won't stay running at first, that gets better too.
It should be fully diluted / run out by now...
I'm at a loss. I'd look at the fuel filter to see if it's gummed up with crud from the inside of the fuel lines. That old rubber will get soft and dissolve in the ethanol.
I can't remember if you're sitting on top of a fuel injected engine or carberetted. Either can get gummed up.
Maybe a heavy dose of carb / injector cleaner would help?