Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 196Get this manual
GEAR HOUSING
4Lubricate ball bearing with Quicksilver Gear LubeRotate inner bearing raceBearing should have smooth actionIf ball bearing sounds or feels rough or has catches, remove and discard bearingRefer to "Disassembly" preceding
NEEDL BEARING
1Clean needle bearings in solvent and dry with compressed air2Replace bearing if needles are rustedfractured, worn, galled badly, discolored, or if area of shaft that bearing contacts is worn or pittedRefer to Shaft" following