Well, I am going in for the much dreaded California smog tomorrow. After rebuilding my 22R engine and carb, it purrs like a kitten.

I want to lean it out as much as I can.

Does turning the idle mixture screw in lean it out, or richen it? I've seen both ways.

 

Tighten to lean. I've never heard of a carb working the other way.

 

The only exceptions I know of are the Amal carbs on my old Triumph Bonneville. Those control the air flow rather than gas flow.