• Free shipping

  • Free help & advice

  • Hassle-free returns

  • Factory direct prices

Flash Sale now on!

FLASHSALE25

Water Pump Impeller – Fits Johnson/Evinrude 4-8 HP (Replaces 389576, 433914, 436137, 777822, 778225)

Regular price $15.99
Shipping calculated at checkout.

Water Pump Impeller – Fits Johnson/Evinrude 4-8 HP (Replaces 389576, 433914, 436137, 777822, 778225) 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 – Fits Johnson/Evinrude 4-8 HP Outboards (Replaces 389576, 433914) is an essential replacement part for maintaining your engine's cooling system. It is designed for Johnson/Evinrude 4HP, 4.5HP, 5HP, 6HP, and 8HP 2-Stroke models (1980–1997) as well as 5HP and 6HP 4-Stroke models (1998 and newer).

It serves as a direct replacement for Johnson/Evinrude part numbers 389576, 433914, 436137, 777822, and 778225, and interchanges with Sierra 18-3091, Mallory 9-45214, GLM Marine 89500, and CEF 500354/500358.

  • Engineered for direct replacement of the original impeller.
  • Constructed from durable neoprene rubber with a brass hub to resist corrosion.
  • Professional installation is recommended for optimal performance.

Part Number Matrix

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

Brand Part Number
Johnson/Evinrude 389576
Johnson/Evinrude 433914
Johnson/Evinrude 436137
Johnson/Evinrude 777822
Johnson/Evinrude 778225
Sierra 18-3091
Mallory 9-45214
GLM Marine 89500
CEF 500354
CEF 500358

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Johnson/Evinrude Outboard 4 2-Stroke 1980–1997 389576 Deluxe models
Johnson/Evinrude Outboard 4.5 2-Stroke 1980–1997 389576
Johnson/Evinrude Outboard 5 4-Stroke 1998 and up 389576
Johnson/Evinrude Outboard 6 4-Stroke 1998 and up 389576
Johnson/Evinrude Outboard 8 2-Stroke 1986–1997 389576

Technical Specs

Product Type
Water Pump Impeller
Installation
Direct replacement, professional installation suggested
Housing Material
Neoprene rubber with brass hub
Dimensions
Overall Diameter: 38.4 mm (1.51 in), Height: 17.9 mm (0.70 in), Shaft Size: 11.2 mm (0.44 in)
Weight
34 g (1.05 oz)
Number of Blades
6
Other Technical Attributes
Brass center hub for durability

What’s in the Box

  • 1 x Water Pump Impeller (389576/433914/436137/777822/778225)

Installation Notes

  1. Disconnect the battery and ensure the engine is off and cool.
  2. Remove the gearcase/lower unit from the outboard motor.
  3. Unbolt and remove the water pump housing to access the old impeller.
  4. Note the orientation of the old impeller blades before removing it.
  5. Clean the inside of the pump housing and inspect it for wear or damage.
  6. Lightly lubricate the new impeller and the inside of the housing with marine grease.
  7. Install the new impeller, turning the driveshaft clockwise to bend the blades correctly.
  8. Reinstall the water pump housing, gaskets, and seals, then reattach the lower unit.
  9. Reconnect the battery and test the engine's cooling water stream (the "telltale") at idle.

Troubleshooting & FAQ

How do I confirm this impeller fits my specific engine?

While this part fits the listed models and years, we strongly advise verifying compatibility with your engine's serial number. Exact cutoff years can vary. Comparing the dimensions and images to your old part is the best way to ensure an exact match before purchasing.

What are the symptoms of a bad or failing water pump impeller?

Common signs include a weak or non-existent water stream from the "telltale" outlet, engine overheating alerts, and reduced engine performance. Visible damage like cracked, brittle, or missing blades on the old impeller also indicates it needs replacement.

How often should I replace my outboard's impeller?

As a general maintenance rule, it is recommended to inspect the impeller annually and replace it every 1–2 years or every 100–200 hours of use, depending on operating conditions (e.g., saltwater vs. freshwater).

What is the advantage of a brass hub?

The brass center hub offers increased durability and corrosion resistance compared to plastic or other materials, especially in saltwater environments. It helps prevent the hub from stripping or spinning on the driveshaft under load.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). 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 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for 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.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • JCB
  • Maestro
  • Mastercard
  • PayPal
  • Union Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.