update

before i proceed with the adjustments carbking suggested i did the following

>replaced fresh 5/16" fuel line from the can to the metal line going to the pump. it took less than 5 seconds to observe a healthy flow from the carb inlet

>replaced the line, pumped 3-5 times and without any prime in the carb it started

>gave a quick check for any obvious vacuum leaks, did not see any

>let it warm up but still having the same issue of stalling when opening the choke

please note this new observation...
even with the motor idling with the choke closed for a while, if it stalls it will not start again without another 3-5 pedal pumps, i thought pumping is not usually necessary for restarts when the motor is warm, i dont know if this is particularly indicative of something?

thanks