[Gaz64]

I would remove the line after your fuel filter before the carburetor, and perform a fuel volume test into a bucket. I would like to see at least 1 quart in 30 seconds.
If that's ok, then I would remove the needle and seats, (note the number of flats, so you can get them back in the ball park), and check for any fuel line debris that maybe restricting fuel flow into the bowls.
If that's ok, I would then pull the spark plugs and post some pics on here of them.
Gary