Sierra 18-3053-1 Water Pump Impeller, Replaces OMC 396725 432954, for Johnson Evinrude 40 HP Outboards 1999-Up

The Sierra 18-3053-1 is a water pump impeller for Johnson and Evinrude (OMC/BRP) outboard engines, designed as a direct replacement for the OEM impeller in the outboard's cooling system water pump. The water pump impeller is the component responsible for drawing raw water through the lower unit and circulating it up through the engine block to keep the powerhead running at a safe operating temperature. As the impeller wears, its vanes lose flexibility and can crack or shear off, reducing water flow and putting the engine at risk of overheating, so this part is a routine maintenance item that should be replaced on a regular service interval or any time cooling performance drops.

This impeller is black in color and ships as a single unit (package quantity of 1). It is built to fit into the existing OMC water pump housing without modification, using the same footprint and drive engagement as the original impeller it replaces. It fits Johnson/Evinrude 40 HP outboards from 1999 and up, and cross-references directly to OMC part numbers 396725 and 432954, making it a straightforward swap for boat owners performing their own water pump service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3053-1
• Product Type: Water Pump Impeller
• Fitment: Johnson/Evinrude (OMC/BRP) 40 HP outboards, 1999-Up
• Replaces (OEM): 396725, 432954
• Color: Black
• Weight: 0.30625 pounds
• Package Quantity: 1
• UPC: 808282342630

Fitment

• Johnson/Evinrude (OMC/BRP) 40 HP outboards, 1999-Up

Replaces (OEM)

• 396725
• 432954

Frequently Asked Questions

What engines does the Sierra 18-3053-1 impeller fit? The Sierra 18-3053-1 fits Johnson/Evinrude (OMC/BRP) 40 HP outboards from 1999 and up.

What OEM part numbers does the 18-3053-1 replace? It cross-references to OMC part numbers 396725 and 432954, so either of those numbers will lead you to the Sierra 18-3053-1 as the correct replacement.

How much does this impeller weigh? The Sierra 18-3053-1 water pump impeller weighs 0.30625 pounds.

How many impellers come in the package? The 18-3053-1 ships as a single impeller, with a package quantity of 1.

What color is the Sierra 18-3053-1 impeller? This impeller is black.

Is the Sierra 18-3053-1 an OEM or aftermarket part? The 18-3053-1 is a Sierra-branded replacement part built to match the fit and function of the original OMC 396725/432954 impeller, rather than a part sourced from Johnson/Evinrude.

When should I replace my outboard's water pump impeller? A worn or cracked impeller reduces cooling water flow and can lead to engine overheating, so the 18-3053-1 should be installed as part of routine water pump maintenance or whenever cooling performance declines.

Can I install the 18-3053-1 myself? Yes, the Sierra 18-3053-1 is sized and configured to install into the existing OMC water pump housing on compatible Johnson/Evinrude 40 HP outboards without modification.

Will the 18-3053-1 fit other Johnson/Evinrude horsepower models? The 18-3053-1 is specified for 40 HP Johnson/Evinrude outboards, 1999 and up; other horsepower ratings and model years use different Sierra impeller part numbers.

What identifies this as the correct part for my engine? Look for OMC part number 396725 or 432954 on your outboard's water pump; both correspond to the Sierra 18-3053-1 impeller.