Factory service manual sez 3/4 turn. That is only a preliminary setting anyway. Must be adjusted on a boat, on the lake, hood on and warmed up. Idle at 700-750 RPM. Turn needles one at a time toward lean till it loses power or sneezes, then back toward rich till it smooths out. Set final idle speed 600-650 RPM in gear. Impossible to guess the RPM without a tachometer, so do the best you can.