does turning the idle adjustment screws in lean out or richen the mixture?

In cuts down the flow-leaner.

Clockwise (in) for leaner.

Set you idle to 600 rpm then back-out the idle mixture scew (counter-clockwise) to see if the idle speeds-up / smooths-out.

If the idle does not change, slowly turn the screw in (clockwise) until you hear the idle speed drop, find that point then back-off 1/2 to 1 full turn.
DD