On the O.S. pumped engine: Any high-speed needle setting more than 1-1/4 turns out from closed will be EXTREMELY-RICH. More than that, and the engine will be so rich you'll be lucky to get it to run. When properly-leaned, it will be about 3/4-turn out from closed.

The hole in the one screw is the hole for the regulator. If you have fuel coming out through it, then the regulator diaphragm is either holed, or the small cone-valve assembly isn't fitting into it correctly.

Here's the setting procedure for all O.S. pumped engines:

http://www.osengines.com/faq/faq-pumped.html