Does this engine have overhead valves? If so check for bent push rods and proper valve lash. The valves not opening properly can cause some issues that seem like it is a carb problem but is really the valves. It may be worth investigating.
No OHV. IT's a 1990's model simple horizontal shaft briggs. Did replace and lap the worn valves and piston rings. Timing is OK. Compression is very good. Seems like carb trouble, but replace everything in the carb.
Did you change the fuel filter? ......and it could have sucked some trash or something into the carb since the rebuild...maybe something residual from in the tank or the fuel line?
It only takes a very little piece of trash to cause a headache.
Not trying to sound like a jerk, but did you soak the carb in a dip for like a 1/2 hour? I soak them really good, clean out any ports I can get to, spray down really good with carb and choke cleaner then use compressed air to blow out everything. You just said you rebuilt it. If not, may want to do that.
I agree with 30yearTech with not getting enough fuel.
On a side note, flush your fuel tank really good to make sure nothing is in there!