1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 62Get this manual
When press-fitting the bearing, be sure to force the inner raceDo not force the outer race Crankshaft main bearings Thoroughly clean the crankshaft, sparingly oil both the upper and lower ball bearings and slowly turn the outer races with your handIf rough spots are noticed, replace the ball bearing (s)Removal As shown, hold the upper and lower bearings with the bearing separator and force the crankshaft out with press