And do I turn clockwise or counter-clockwise for more air IN to the carb?

 

carb pic
Its number 17 in this pic.
On almost all 4 strokes, they are mixture screws. Most two stokes have air screws. Going out, gives you more (mixture on 4 stroke or air on two stroke).
Easiest way to tell,if its a mixture screw or air screw, if its between the slide and motor, its a mixture screw. If its between the slide and the air cleaner, its a air screw.
So, going out, is richer, on your vinson.

 

The man speaks true. Listen well.