what about the float level? If it was set
really low, gas would be difficult to get into the throat and choking would help.
It still sounds like a plugged carb jet to me.
Just had a thought. DJ54 mentioned a vacuum leak. I have a 351 Ford in my motorhome that sat for a couple of years and after starting it, it ran lousy, needed choking. I couldn't find anything wrong with it. Rebuilt the carb and it was better but still ran crappy. I replaced or removed all the unnecessary air hoses and pollution parts thinking it might be a vacuum leak. Still no change. I worked on this for weeks and could not figure why it ran so bad.
On a hunch, I took some carb cleaner and sprayed it around the intake manifold where it met the head, very lightly all around the intake. Instantly the engine would roar to life until the spray was sucked in and gone.
I tightened all the intake manifold bolts, as they were a tiny bit loose, but it made no difference.
I had a bad intake manifold gasket apparently. After several years of sitting, the gasket failed. I replaced it and all was good. Not easy when it's on one of the motorhomes where the engine is half out front and half in the cab.
You might try that trick with the carb cleaner spray. If you do, do it when the engine is first started, before the exhaust manifold gets hot enough to ignite your spray.
You do this at your own risk ! But it might tell you if your gasket is faulty.
