Sierra 18-3059 Water Pump Impeller - Replaces OMC 395864, 397131, 435821, 5001593 - Evinrude 140-175 HP Outboards

The Sierra 18-3059 is a water pump impeller engineered as a direct replacement for the impeller used in Evinrude outboard water pump kits across a wide range of 140, 150, and 175 HP models. As the rotating component inside the outboard's water pump housing, the impeller draws raw water from the intake and circulates it through the powerhead cooling passages, keeping engine temperatures in check during operation. Its flexible vanes flex and release as the rotor turns, creating the pumping action that moves cooling water continuously while the engine runs.

Built from plastic for consistent vane flexibility and wear resistance, this impeller is sized to fit directly into the water pump housings used across the listed Evinrude horsepower and year ranges, including 20 inch and 25 inch shaft length configurations. It is intended as a straightforward, drop-in replacement during routine water pump service or when replacing a worn or damaged impeller that is no longer sealing and pumping efficiently. Replacing the impeller is a standard maintenance item recommended on a routine service interval to avoid overheating caused by a worn impeller losing its vane tension.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3059
• Item Type: Impeller
• Material: Plastic
• Weight: 0.4 pounds
• Package Dimensions: 7.13 inches L x 1.31 inches H x 6 inches W
• Country of Origin: Italy
• Unit Count: 1
• Included Components: Impeller
• UPC: 030999315151

Fitment

• Evinrude 140 HP, 1979-Up
• Evinrude 140 HP, 25 inch shaft, 1993
• Evinrude 140 HP, 25 inch shaft, 1994-2000
• Evinrude 150 HP, 1979-Up
• Evinrude 150 HP, 20 inch shaft, 1993 & Up
• Evinrude 150 SL, 20 inch shaft, 1994-98
• Evinrude 150 EL, 20 inch shaft, 1996-98
• Evinrude 150 HP, 25 inch shaft, 1993 & Up
• Evinrude 150 DI, 1997 & Up
• Evinrude 150 HP, 2000 & Up
• Evinrude 175 SL, 20 inch shaft, 1994-98
• Evinrude 175 EL, 20 inch shaft, 1996-98
• Evinrude 175 HP, 25 inch shaft, 1993 & Up

Replaces (OEM)

• OMC 395864
• 397131
• 435821
• 5001593

Frequently Asked Questions

What is the Sierra 18-3059 impeller used for? It is the rotating water pump impeller that draws raw water into an Evinrude outboard and circulates it through the powerhead to keep the engine cool while running.

Which outboards does the 18-3059 impeller fit? The 18-3059 fits Evinrude 140 HP models from 1979 and up (including 25 inch shaft units from 1993 and 1994-2000), 150 HP models from 1979 and up including SL, EL, DI, 20 inch, and 25 inch shaft variants through 2000 and up, and 175 SL, EL, and 25 inch shaft models.

Does the 18-3059 replace OMC part 395864? Yes, the Sierra 18-3059 is a direct cross-reference replacement for OMC 395864, along with OMC/OEM numbers 397131, 435821, and 5001593.

What is the 18-3059 impeller made of? It is made of plastic, formed into flexible vanes that seal against the pump housing to move cooling water as the rotor turns.

How much does the 18-3059 impeller weigh? The Sierra 18-3059 impeller weighs 0.4 pounds.

Is the 18-3059 a genuine Sierra part or a generic aftermarket copy? 18-3059 is the Sierra manufacturer part number itself, sold as a cross-reference equivalent to the listed OMC/OEM numbers rather than a generic no-name copy.

What comes in the box with the 18-3059? The package includes one impeller (unit count of 1); it does not include the pump housing, gaskets, or the plate and cup components listed separately in the water pump kit lineup.

How do I know if my water pump impeller needs replacing? Reduced water flow, engine overheating, or a visibly worn or cracked vane on the old impeller are signs the Evinrude water pump impeller, such as the 18-3059, needs replacement.

Does the 18-3059 come with a warranty? The Sierra 18-3059 impeller carries a limited warranty covering manufacturing defects.

Where is the 18-3059 impeller manufactured? The Sierra 18-3059 impeller is manufactured in Italy.

What size shaft outboards use the 18-3059? The 18-3059 fits both 20 inch and 25 inch shaft Evinrude outboards depending on the specific HP and year, as listed in the fitment details for this part.

Is the 18-3059 the correct impeller for a 150 DI outboard? Yes, the Sierra 18-3059 impeller is the listed impeller for Evinrude 150 DI outboards from 1997 and up.