Carter BBS Slant 170cui idle problems

Under that plug is a screw, I would make a definite mark on the side of the carb as a starting reference point. Count the number of turns and direction. You can go way too rich or way to Lean. If I remember correctly clockwise will rich in the mix. What is actually being adjusted is the spring tension. The air bleed size is not adjustable. Upon further investigation I think I got this backwards. The actual spring tension is not adjustable but I think the size of the air bleed is