Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP (Replaces 396644, 389844)

$26.99

Shipping calculated at checkout.

Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP (Replaces 396644, 389844) is backordered and will ship as soon as it is back in stock.

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 the essential components needed to service the cooling system on Johnson/Evinrude 4-8 HP, 2-stroke outboard engines manufactured from 1980 to 2005. It ensures proper water circulation to prevent overheating and maintain engine performance.

It is a direct aftermarket replacement for Johnson/Evinrude part numbers 396644 / 0396644 and 389844, and also cross-references with Sierra 18-4529 and QuickMarine 0396644.

Engineered for direct replacement of OEM components for a straightforward installation.
Designed for use in gasoline-powered marine outboard engines.
Includes the impeller, wear plate, housing, gaskets, and mounting hardware for a complete service.

Part Number Matrix

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

Brand	Part Number
Johnson/Evinrude	396644 / 0396644
Johnson/Evinrude	389844
Sierra	18-4529
QuickMarine	0396644

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This kit is designed for a range of Johnson/Evinrude outboards. Please verify your engine's horsepower and year to ensure correct fitment, as models can vary.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Johnson/Evinrude	Various	4	2-Stroke	1986–1992	396644, 389844
Johnson/Evinrude	Various	5	2-Stroke	1980–1983, 1996–2001	396644, 389844
Johnson/Evinrude	Various	6	2-Stroke	1984–2001, 2003–2005	396644, 389844
Johnson/Evinrude	Various	8	2-Stroke	1980–2001, 2003–2005	396644, 389844

Technical Specs

Product Type: Water Pump Impeller Kit (without housing)
Installation: Direct replacement for OEM components
Fuel Type: Gasoline (marine outboard engines)
Housing Material: Nylon PA66 Plastic
Housing Color: Black
Weight: 125 g (4.4 oz)
Warranty: Standard 30-day return period
Other Technical Attributes: Includes impeller, wear plate, gaskets and mounting screws

What’s in the Box

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

Installation Notes

For safety, disconnect the negative battery cable and remove spark plug wires.
Place the outboard transmission in neutral and remove the bolts securing the lower unit (gearcase).
Carefully lower and separate the gearcase from the engine's upper section.
Locate the water pump assembly on top of the gearcase and remove the housing bolts.
Slide the housing off to expose the impeller. Remove the old impeller, drive key, gaskets, and wear plate.
Clean all surfaces meticulously, ensuring no old gasket material or debris remains.
Install the new wear plate and gaskets. Apply a light amount of marine grease to the new impeller and the inside of the housing cup.
Seat the new drive key on the driveshaft flat and slide the new impeller on, turning the driveshaft clockwise to correctly orient the vanes.
Reinstall the housing and tighten bolts to the manufacturer's specified torque.
Reattach the lower unit to the midsection, ensuring the driveshaft, shift shaft, and water tube are properly aligned.
Once fully assembled, start the engine in water and verify a strong, consistent stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my specific engine?

This kit is designed for the Johnson/Evinrude 4-8 HP 2-stroke outboard series from 1980–2005. The most reliable method to ensure a match is to cross-reference your existing part number with those listed in our Part Number Matrix. Always compare the parts visually with your old ones before installation.

What are the signs of a bad water pump impeller?

The most common sign of a failing impeller is a weak, sputtering, or non-existent water stream from the "tell-tale" cooling outlet. Other indicators include engine overheating alarms or steam from the exhaust. During a visual inspection, a worn impeller may have cracked, brittle, or permanently curved vanes.

How often should the impeller be replaced?

As a crucial part of preventative maintenance, we recommend inspecting the impeller annually. For optimal reliability, it should be replaced every 1 to 2 years, or approximately every 100-200 hours of operation. Replacement frequency should be increased if operating primarily in saltwater or sandy/silty conditions.

I read a review that the drive key did not fit correctly. Is this a common issue?

Our kits are manufactured to meet or exceed OEM specifications for the listed models. However, due to slight variations across decades of engine production, fitment issues can occasionally occur. We strongly advise comparing the new key to your original part before installing. If it does not match, please contact our support team for assistance.

Is this an OEM part or an aftermarket replacement?

This listing is an aftermarket replacement (not OEM). It has been engineered to meet OEM-level specifications with comparable or superior materials. All our parts are manufactured in an ISO 9002 certified facility and are batch-inspected to ensure consistent quality and performance.

What are the shipping costs and delivery times?

We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free on all orders. Expedited shipping options, where available for your location, will be presented at checkout.

What is your warranty and return policy?

This part is covered by a 1-year limited warranty against manufacturing defects under normal marine use. If you encounter any issues, please contact our support team with your order details. Returns of unused parts in their original condition are accepted within our standard return window. You can find more details on our policy page or reach out for specific instructions.

Safety & Important Info

Verify images/specifications vs 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 QC.

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