before you throw it away!!!

IF it were mine, I would tear it all down, clean and polish and restore it.

Then go at it again on a stand, (so I am not bending over) and get it figured out.

Some mods I have been successful with OS airbleeds are:
drilling out the air intake 'hole'
grinding the needle 'valve' screw to a fine point
OR just taking out the hole air screw assembly (had 1 run like that for a year)

Seriously I will pay for dead OS engines...

All the best