Alextran,

turning the regulator out (counter clockwise) is to richen the mixture. regulator in (clockwise) is to lean.

Try below with Tach.

Start engine, slowly throttle up to full throttle. Set the high speed needle.

Throttle down to 3500 rpm. if the rpm drops, you are rich in the midrange. If the rpm increases and drop down, you are lean.

It sounds a little bit strange to have one turn out on the regulator and still lean.

Also, Omega (red or pink color) has castor right?

I ran my first YS with castor blend fuel (Omega), I had real hard time removing the carbon deposit.

Since then, I only use full synthetic oil fuel.

Hope this helps,