If you are sure it is flooding, that is unlikely to have anything to do with the mixture screws. Here is Zama's trouble-shooting guide:
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As a starting-point for mixture adjustment, I've seen the following settings recommended on the internet:

High speed 5/8 of a turn from fully clockwise.
Low speed 1 1/4 turns from fully clockwise.
However, always begin by finding out how it is set to begin with, before you adjust anything. Note where the screw slot is pointing, then turn it gently clockwise until you feel it lightly touch its stop. Note how far you have turned it. Then put it right back where you found it.

The idle speed screw is simply adjusted so that the chain does not quite move when the saw is idling.