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Water Pump Impeller Kit – Fits Johnson/Evinrude 4–8 HP Outboards (Replaces 396644, 0396644)

Regular price $34.99
Shipping calculated at checkout.

Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller Kit provides a reliable cooling system solution for Johnson and Evinrude outboard engines. It is designed for a precise, vehicle-specific fit on 4–8 HP engines manufactured from 1980 to 2005, covering both 2-stroke and 4-stroke models.

It serves as a direct replacement for Johnson/Evinrude parts 396644/0396644, Sierra 18-4529, and GLM 12065.

  • Installation Method: Direct replacement
  • Connection Type: Direct drive
  • Kit includes impeller, wear plate, gaskets, and all necessary mounting hardware.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.

Brand Part Number
Johnson/Evinrude 396644 / 0396644
Sierra 18-4529
GLM 12065

Engine & Model Compatibility

Confirm your engine model and year in the table below.

For Johnson/Evinrude owners: This kit fits a wide range of small horsepower outboards from 1980 through 2005. Please verify your specific model and year.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Johnson/Evinrude Outboards 4 2-Stroke 1986–1992 396644
Johnson/Evinrude 4 Deluxe 4 2-Stroke 1985–1988 396644
Johnson/Evinrude Outboards 4.5 2-Stroke 1980–1984 396644
Johnson/Evinrude Outboards 5 2-Stroke 1980–1983, 1996–2001 396644
Johnson/Evinrude Outboards 5 4-Stroke (128cc) 1998–2004 396644
Johnson/Evinrude Outboards 6 2-Stroke 1984–2001, 2003–2005 396644
Johnson/Evinrude Outboards 6 4-Stroke (128cc) 1998–2004 396644
Johnson/Evinrude Outboards 7.5 2-Stroke 1980–1985 396644
Johnson/Evinrude Outboards 8 2-Stroke 1980–2001, 2003–2005 396644

Technical Specs

Product Type
Water Pump Impeller Kit
Fitting Type
Vehicle specific fit
Housing Material
Plastic
Dimensions
Height: 6.5″; Width: 10.5″; Length: 9.5″
Weight
176 g (6.2 oz)

What’s in the Box

  • 1 x Impeller Assembly (389576, 18-3091)
  • 1 x Drive Key (331130, 18-3026)
  • 1 x Impeller Housing Cup (324641, 18-4551)
  • 1 x Impeller Housing Plate (324640, 18-4578)
  • 2 x Impeller Housing Gasket (325040, 18-99156)
  • 1 x O-Ring (303191, 18-7413)
  • 1 x Grommet (321129, 18-1827)
  • 1 x Grommet (302497, 18-3329)
  • 4 x Screws (324430, 18-4277)
  • 1 x Pin (300611)

Installation Notes

  1. Disconnect the battery and spark plug wires for safety.
  2. Position the outboard to access the lower unit and drain the gearcase oil.
  3. Remove the lower unit bolts and detach the lower unit from the driveshaft housing.
  4. Unbolt and remove the water pump housing to access the old impeller.
  5. Remove the old impeller, key, gaskets, and wear plate. Clean all surfaces thoroughly.
  6. Install the new wear plate, gaskets, and impeller key.
  7. Slide the new impeller into place, rotating the driveshaft in its normal direction of rotation to seat the vanes.
  8. Reassemble the housing with new gaskets and O-rings, ensuring a tight seal.
  9. Reattach the lower unit, refill the gearcase oil, and reconnect the battery.
  10. Test the engine using a water source (flushing muffs) to confirm proper water flow.

Troubleshooting & FAQ

How do I know if this impeller kit will fit my motor?

The surest way is to match your engine's model and year against our compatibility table. You can also cross-reference your existing part number with the ones listed in our Part Number Matrix.

What are the signs of a failing water pump impeller?

Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent stream of water from the "telltale" outlet, and a dry, brittle, or cracked appearance on the old impeller upon inspection.

How often should I replace my outboard's impeller?

As a general maintenance guideline, it is recommended to inspect and/or replace the impeller every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).

Is this a difficult part to install myself?

For those with basic mechanical skills and the right tools, this is a manageable DIY job. However, due to the importance of a proper seal and correct assembly for engine safety, we recommend professional installation if you are not completely comfortable with the process.

Can I buy just the impeller without the full kit?

While some suppliers may offer the impeller alone, this complete kit is recommended. It includes all necessary gaskets, O-rings, and the wear plate, which often wear out at the same rate as the impeller and are critical for restoring proper pump performance and preventing leaks.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

This product is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition. See our policy page or reach out for instructions.

Safety & Important Info

  • Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
  • This is an aftermarket replacement, not an OEM component.
  • Professional installation is recommended for safety and performance.

About Sea Sierra

  • Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
  • Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
  • Manufacturer-Direct Value — Fair pricing without compromising on materials or quality control.

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