Surging / fuel delivery problem 4.5 HP Briggs Quantum

I have a 1996 Murray 22" with the 4.5 HP Quantum XTE engine, model number: 127802. It sat for several years and I took the carb apart, soaked it in cleaner for about a week, took a wire and ran it through all passages I could find, more carb cleaner, replaced the needle/seat/float/o-rings, etc. When cold, engine starts right up but dies unless a pump the primer bulb constantly. Once warm, it runs but surges unless I put a tiny bit of pressure on the carb spring, then it runs great (I'm guessing this closes the choke a little).

Seems like a fuel delivery issue but I can't figure out what may be restricted. No vacuum leaks that I can detect. Any suggestions?

Surging / fuel delivery problem 4.5 HP Briggs Quantum