Water Pump Impeller with Key and Gasket – Fits Johnson/Evinrude 5.5-7.5 HP (Replaces 763735, 387361)
Water Pump Impeller with Key and Gasket – Fits Johnson/Evinrude 5.5-7.5 HP (Replaces 763735, 387361) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Impeller with Key and Gasket – Fits Johnson/Evinrude 5.5...
Product Details
This aftermarket Water Pump Impeller with Key and Gasket is a direct replacement for Johnson/Evinrude 5.5 HP (1954–1979), 6 HP (1954–1979), and 7.5 HP (1954–1958) outboard engines. It's an essential component for restoring your engine's cooling system to optimal performance.
This kit directly replaces Johnson/Evinrude part numbers 763735, 0763735, 387361, 0387361, 777831, 0777831, and interchanges with Sierra 18-3090, Mallory 9-45210, GLM 89490, and SEI 96-399-02.
- Engineered for models equipped with the original metal pump housing.
- Complete kit includes the impeller, housing gasket, and drive shaft key.
- Designed as a direct-fit replacement for straightforward installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude | 763735 / 0763735 |
| Johnson/Evinrude | 387361 / 0387361 |
| Johnson/Evinrude | 777831 / 0777831 |
| Sierra | 18-3090 |
| Mallory | 9-45210 |
| GLM | 89490 |
| SEI | 96-399-02 |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
| Brand | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Johnson/Evinrude | 5.5 HP | 2-Stroke | 1954–1979 | 763735/0763735 | For models with metal pump housing |
| Johnson/Evinrude | 6 HP | 2-Stroke | 1954–1979 | 763735/0763735 | For models with metal pump housing |
| Johnson/Evinrude | 7.5 HP | 2-Stroke | 1954–1958 | 763735/0763735 | For models with metal pump housing |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct replacement
- Connection
- Direct shaft connection
- Housing Material
- Rubber (impeller), metal (housing)
- Housing Color
- Black/Natural rubber
- Overall Diameter
- 38.80 mm
- Height
- 18.60 mm
- Shaft Diameter
- 11.20 mm
- Weight
- 40 g (0.04 kg)
- Fitting Type
- Direct fit with shaft key
- Blades/Vanes
- 6
What’s in the Box
- 1 x Water Pump Impeller (Replaces 763735)
- 1 x Impeller Housing Gasket
- 1 x Drive Shaft Key (Replaces 0321130)
Installation Notes
- Disconnect the spark plug leads and shift the outboard into neutral.
- Remove the lower unit (gearcase) mounting bolts and carefully separate it from the upper housing.
- Unbolt and remove the water pump housing cover to access the old impeller.
- Take note of the old impeller's blade direction, then remove it and the drive key from the shaft.
- Thoroughly clean the pump housing interior and mating surfaces.
- Install the new drive key into the shaft, then slide the new impeller on.
- Apply a thin coat of marine grease to the inside of the pump housing to ease installation.
- Seat the new gasket, reinstall the housing, and tighten the bolts to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring the driveshaft and water tube align correctly.
- Once assembled, test the engine in water to confirm a strong and steady stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this impeller fits my engine?
This impeller is specifically designed for Johnson/Evinrude 5.5 HP & 6 HP (1954–1979) and 7.5 HP (1954–1958) outboards that use a metal water pump housing. The best way to ensure compatibility is to verify your original part number against the references in our Part Number Matrix.
What are the signs of a failing water pump impeller?
Common signs include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, or steam from the exhaust. Upon inspection, a failing impeller may appear cracked, dry, brittle, or have deformed or missing blades.
How often should I replace my impeller?
For preventative maintenance, it's recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation. Replacement frequency should be increased if you operate in saltwater or sandy/silty water conditions.
What tools are needed for installation?
You will typically need a basic socket/wrench set, screwdrivers, a gasket scraper or plastic blade for cleaning, and marine-grade grease. Always refer to your engine's service manual for specific tool requirements and torque specifications.
Does this kit include the metal pump housing?
No, this kit contains the rubber impeller, the housing gasket, and the drive shaft key. It is designed to be installed into your existing metal pump housing.
What's the difference between this and an OEM part?
This is an aftermarket part designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function. It provides a reliable, cost-effective alternative to the original branded component.
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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