Unless you're pretty skilled with carbs (not!
), I'd look for an OEM replacement...
I wish I was up there,... I'm still sure you can get that screw out (like others have said,... it's not torqued in there... all you have to do, is find a way to catch any tool to some tiny snag, and it will come out)
I'm so fustated!...
...
IDEA!.. pull the carb, and take it to a machine shop... they'll probably figure a way to get it out in 2 minutes, and charge you $5 or $10 bucks...
Can't hurt to try... you're gonna' pull it off to replace it anyway...
...