Hi: I have a 1994 90hp mercury 2 stroke serial# OG 280021. could someone explain way the preset idle adjment setting on #1 carb is a 1/2 turn out and the #2and#3 carbs are 1 1/2 turns out? Then to adjust after warm up and in gear do you adjust all 3 carbs the same way? Adjust screw in until...