Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 156Get this manual
2Remove balance piston nutSeparate balance piston from balance rod 55814 Nut (30mm) Piston 55816
a Can Rod Bolts (4)
3Remove crank case cover boltsSeparate crank case cover from cylinder block4Remove dowel pins
6Remove carbon ridge from the cylinder bore using burr knifePistons should be taken out through the cylinder head side of blockNOTE: Keep each piston, connecting rod, and cap together as an assembly