Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 268Get this manual
9Apply Loctite 271 to .0 of large diameter seal10With seal lip FAC ING TOWARDS SMALL SHOULDER of Mandrel 91-817007, press seal into carrier until mandrel bottoms on carrierJ
Gear Housing Reassembly
IMPORTANT: The gear case assembly does not have any shims for the gear assembliesBacklash cannot be adjustedThe technician must verify that all bearing races are firmly seated in the gear case during reassembly and that all gear case components are in serviceable conditionPriorto installing the seal carrier and water pump assembly on the drive shaft, the FORWARD gear should be held stationary with screw driver or similar toolWhile pulling up on the drive shaft, lightly turn the shaft back and forth tightcticking" sound should be heard indicating the presence of backlash between FORWARD and PINION gearsIf this backlash is not present, the pinion gear race andior forward gear race are not fully seatedRaces should be removed and inspected for debrisReinstall races and check backlashIf backlash is still not present, replace gear housing