1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 187Get this manual
POWER UNIT 6-44 Cylinder bore wear (difference) Using cylinder gauge, measure cylinder bore in both axial (vertical line, following crankshaft) and transverse (horizontal line across crankshaft) directions at two positions as shown in figure09900-20530Cylinder gauge set Check for followingDifference between measurements at the two positions (taper) Difference between axial and transverse measurement (outof-round)Cylinder bore wear (difference) Service limit0.10 mm (0.039 in If measurement exceeds service limit, rebore or replace cylinder