2006-2010 Suzuki DF150 / DF175 4-Stroke Outboards Service Manual, Page 412Get this manual
LOWER UNIT
6Align dial gauge pointer at 90 to the mark on the backlash indicator tool and read backlash on dial gauge by lightly moving driveshaft clockwise and counterclockwise by handGear backlash: Approx0.3 0.5 mm (0.012 0.020 in)