Any Walbro in good condition will pump fuel 4 feet straight up..If the inlet needle is sticking or the pulse is leaking it will not...Take the cover off, the one with 4 screws..blow into the fuel inlet..If the inlet needle is leaking you have a problem It should not unseat unless you push the lever down...It take at least 10 lbs pressure to unseat it, you can't possibly blow that hard...Be sure the gasket is against the carb with the diaphragm on top when you put it back together...see that the pulse holes are not blocked or leaking in the block under the carb..
Choking by closing off the intake and fuel pumping after the engine is running are not related...Choking uses the upstroke of the piston to pull fuel from the tank through the inlet needle, pumping uses crankcase pulses to pull fuel into the chamber under the diaphragm, where intake through the carb siphons fuel from the chamber thorough holes regulated by the carb adjustment needles...