2003+ Suzuki DF9.9/DF15 four stroke outboard motors service manual, Page 126Get this manual
POWER UNIT
Cylinder bore wear (difference) Measure the cylinder bore in the thrust and axial directions at the three positions A, and as shownCheck for the followings: Difference of the measurements at two positions (Taper) Difference between the thrust and axial measurement (Out-of-round)