1973 Ford F-100 F100 390 4bbl

Sure could use a lot more detail. How long does it run? A minute? An hour? Does it shut off at highway speed? Have you looked down the middle of the carburetor to see if there's two nice strong sprays of fuel when you work the throttle by hand? Have you checked for loss of spark?

Have you looked down the middle of the carburetor to see if there's two nice strong sprays of fuel when you work the throttle by hand?

If you're losing fuel, a good suspect is the pickup screen in the gas tank. They will collapse and block the pipe, then will slowly stretch out again when the engine is stopped.

Also look around the tank for wetness indicating a leak. If that leak is up high enough, air will get sucked in rather than fuel getting drawn from the tank.

I'm happy it's running, but how did it start and run for a minute if the gas went bad?

Did you replace the sock on the end of the pickup tube?

Have you solved the problem? I don't think the ethanol is the issue. I have three cars with carburetors and don't have an issue. There originally was concern that the alcohol would act as a cleaner and break off pieces of debris that would clog filters, but the problems seem to be more common when the fuel sits a long time. People who use ethanol in generators, compactors, and cement mixers on the job don't seem to have trouble either. A friend who runs a small engine repair shop showed me a jar of old ethanol, and it was cloudy from mold growing in it. That is supposedly what plugs things up.

This isn't my area of expertise, and I have no reason to doubt my friend. This is just offered for your consideration.

Dandy. I'm happy you knew to get that oil out of there.