Mike,

even with a new refurbish AFM it needs some adjustment ... I don't think
you need to open it and do the whole procedure... I do have some problem
with 2 refurbished AFM and on one the engine runs quite rich... black sooth
on the the tail pipe... on another one it's running lean lacking power...

as for your case, I would adjust the screw using a #5, turn it counter
clockwise to let more air in (top left, in green in this Samba link)

http://www.thesamba.com/vw/forum/viewtopic.php?t=356377

so...

- check all your vacuum hoses..

- make sure the the AFM connector is clean and plugged in..