Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 262Get this manual
Inspection Upper Drive Shaft Bearing
1Inspect bearing for rust, roughness or discoloration from lack of lubricant200 NOT remove bearing from drive shaft unless bearing must be replaced as removal process will
Pinion Gear Bearing
1Inspect bearing for rust, roughness or discolor ation from lack of lubricant2If bearing is damaged, bearing and race must be replaced as an assembly3If race appears to have spun in drive shaft boregear case housing must be replaced
damage bearing3If bearing must be replaced, position drive shaft assembly in vise (jaws of vise supporting only bearing) and while holding drive shaft, strike top
of drive shaft with lead hammer and drive bearing