1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 57Get this manual
Maximum allowable taper: 0.08 mm (0.003 in) Maximum allowable out-of-round: 0.05 mm (0.002 in) Hone the cylinder bore using hone with fine stonesHone no more than required to remove all wear marksCylinder bore Standard 56 +0.02 mm
Wear limit