Water Pump Impeller – Fits Evinrude Johnson 1.2–6 HP (Replaces 387361, 763735, 777831)

$11.50 $18.00

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Water Pump Impeller – Fits Evinrude Johnson 1.2–6 HP (Replaces 387361, 763735, 777831) is backordered and will ship as soon as it is back in stock.

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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 Evinrude Johnson 1.2–6 HP (Replaces 387361, 763735, 777831) is designed for specific Evinrude Johnson outboard engines. It provides a reliable direct replacement for 1.2 HP (1986–1990), 2 HP (1985–1990), 4 HP (1976–1980) models with a 90-degree gearcase, and 6 HP (1979) models, restoring your engine's cooling system performance.

This component serves as a direct interchange for multiple OEM and aftermarket part numbers, including Johnson/Evinrude 387361, 763735, 777831, Sierra 18-3090, and Mallory 9-45210.

Engineered for direct OEM replacement fit and function.
Constructed from durable neoprene rubber with a brass insert for longevity.
Covered by a 1-year warranty against manufacturing defects.

Part Number Matrix

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

Brand	Part Number
MARKGOO	763735/0763735
Johnson/Evinrude	387361/0387361
Johnson/Evinrude	763735/0763735
Johnson/Evinrude	777831/0777831
Sierra	18-3090
Mallory	9-45210
CEF	500354
GLM	89490

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Evinrude/Johnson owners, please verify your engine's horsepower, year, and any specific notes (like gearcase type) to ensure a perfect match.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Johnson/Evinrude		1.2 HP		1986–1990
Johnson/Evinrude		2 HP	2-Stroke	1985–1990	387361, 763735
Johnson/Evinrude	Outboard	4 HP	2-Stroke	1976–1980	387361, 763735	90 degree gearcase only
Johnson/Evinrude	Outboard	6 HP	2-Stroke	1979	387361, 763735

Technical Specs

Product Type: Water Pump Impeller
Installation: Direct OEM replacement
Housing Material: Neoprene rubber with brass insert
Height: 18.6 mm (0.73 in)
Overall Diameter: 38.8 mm (1.53 in)
Shaft Diameter: 11.2 mm (0.44 in)
Weight: 32–40 g (1.13–1.4 oz)
Blades: 6
Warranty: 1-year against manufacturing defects (JLM Marine)

What’s in the Box

1 x Water Pump Impeller (Replaces 0763735/763735/0387361/387361/0777831/777831/18-3090)

Installation Notes

Disconnect the battery and spark plug wires for safety.
Place a drain pan under the lower unit and remove the drain/fill screws to empty the gear oil.
Unbolt and carefully lower the gearcase (lower unit) from the outboard's driveshaft housing.
Locate and remove the water pump housing bolts to access the old impeller.
Note the orientation of the old impeller blades before removing it from the driveshaft.
Clean the housing interior and inspect it for wear, scoring, or corrosion.
Install the new impeller, applying a light coat of marine grease to the housing and rotating the driveshaft in its normal direction to bend the blades correctly.
Reassemble the water pump housing, ensuring all seals and gaskets are correctly seated.
Re-install the lower unit, refill with fresh gear oil, and reconnect the battery/plugs.
Start the engine in water and verify water is exiting the "telltale" port, indicating a functional cooling system.

Troubleshooting & FAQ

How do I know if this impeller fits my specific engine?

The best way to confirm is by matching your original part number to those listed in our Part Number Matrix. Additionally, check your engine's brand, HP, and year against the compatibility table. For the 4 HP model, ensure you have the 90-degree gearcase.

What are the signs of a failing water pump impeller?

Common signs include a weak or no water stream from the "telltale" indicator, engine overheating alarms, or a noticeable decrease in engine performance. A brittle, cracked, or deformed impeller upon inspection also indicates it's time for replacement.

How often should I replace my impeller?

For preventative maintenance, 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).

Why does the impeller have a brass insert?

The brass insert provides a durable, corrosion-resistant hub that fits securely onto the driveshaft. It prevents slippage and ensures a reliable mechanical connection between the shaft and the neoprene blades for consistent pumping action.

Is this part difficult to install myself?

Installation requires basic mechanical skills and tools to drop the lower unit of your outboard. While many boat owners perform this maintenance themselves, we recommend professional installation if you are not comfortable with the process to ensure safety and correct function.

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.

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