Sierra's 18-4531 Water Pump Repair Kit without Housing is designed for use in the following Mercury outboard engines: 25 HP (4-Stroke), 30 HP (2 Cylinder), 30 HP (4-Stroke), 40 HP (2 Cylinder), 40 HP (3 Cylinder), 40 HP (4-Stroke), 50 HP (3 Cylinder), 50 HP (4-Stroke), and 50 HP Bigfoot (4-Stroke). The kit contains: (1) Sierra 18-1838 Short Seal (1-3/4"), (1) Sierra 18-1839 Long Seal (2-1/4"), (2) Sierra 18-2560 Impeller Washer Gaskets, (1) Sierra 18-0345 Water Pump Gasket, (1) Sierra 18-99155 Water Pump Gasket, (1) Sierra 18-4577 Outer Wear Plate, and (1) Sierra 18-3057 Impeller. It is interchangeable with Mercury Marine 821354A1 and 821354A2. Each Sierra product meets or exceeds the original equipment part it replaces.
