1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 54Get this manual
Oil seal housing 1After removing the cylinder head, dismount the engine from the engine stand and place it on bench with the cylinder head side downNOTE: _ 1Thoroughly clean the bench top and use care not to scratch the mating surface of the cylinder head and cylinder2Keep the piston at 10 mm (0.4 in) before TOC Crankcase 1Remove the crankcase bolts (M6 and M8), insert slottedhead screwdriver between the tabs on both the right and left sides of the crankcase and cylinder and pry the two apartNOTE: Be careful not to insert the screwdriver between the crankcase and cylinder