1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 179Get this manual
Water Pump (Design 1) 1If water tube seal stayed on water tube (inside of drive shaft housing) when gear housing was removed, pull water tube seal from water tube2Replace water tube seal, if damaged3Remove bolts, washers, and isolators4Remove cover
7Inspect impellerReplace impeller if any of the following conditions exist: Impeller blade(s) are cracked, torn, or worn Impeller is glazed or melted (caused by operation without sufficient water supply) Rubber portion of impeller is not bonded to impeller hub8Remove plate and gasket9Replace plate if groove(s) (other than impeller sealing bead groove) in plate are more than 0.030I (0.762mm) deep
19212Water Tube SealBolts (4 each)Washers (4 each)Isolators (4 each)Cover