Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 272Get this manual
Water Pump 1Install water pump seal carrier2Install exhaust deflector plate, if removed
IMPORTANT: II impeller being installed has been previously used and vanes have takenset," DO NOT INSTALL THE IMPELLER WITH THE VANES REVERSED FROM THEIR PREVIOUSSET" AS VANE BREAKAGE WILL OCCUR SHORTLY AFTER UNIT IS RETURNED TO SER VICE4Install impeller and nylon washer
a Seal Carrier
bExhaust Deflector
3Install base gasket, base plate, pump cover gas-
ket (NEOPRENE STRtP FACES UP), nyton
washer and impeller key