Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 369Get this manual
2 Inspect bushing O-rings for cuts and abrasionsReplace O-rings if necessary
Installing Drive Gear (for Oil Injection Pump) Onto Crankshaft
IMPORTANT: The removal of the oil pump drive gear from the crankshaft requires that the lower crankshaft ball bearing be removed firstThe removal process of this bearing will normally damage the bearing thus requiring its replacementDO NOT remove the oil pump drive gear unless it is damagedREMOVAL OF DRIVE GEAR
aO-rings
Remove lower ball bearing from crankshaft as follows: aRemove retaining ring using pair of snap ring pliersReinstall bushingseal assembly