Water Pump Impeller Kit – Fits Johnson/Evinrude 20-35 HP (Replaces 393630)

$32.00

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Water Pump Impeller Kit – Fits Johnson/Evinrude 20-35 HP (Replaces 393630) 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).

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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 is designed for direct fitment on Johnson/Evinrude 20-35 HP 2-stroke outboard engines manufactured from 1980 and later. It provides a complete solution for servicing or rebuilding the water pump to ensure optimal engine cooling and prevent overheating.

It serves as a direct aftermarket replacement for Johnson/Evinrude OEM part 393630 and interchanges with Sierra 18-3382, GLM 12960, and Mallory 9-48300.

Installs as a direct OEM-equivalent replacement.
Features a durable metal/aluminum housing with a 6-blade neoprene rubber impeller.
Includes a comprehensive set of gaskets, seals, and hardware for a full-service installation.

Part Number Matrix

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

Brand	Part Number
Johnson/Evinrude	393630 / 0393630
Sierra	18-3382
GLM	12960
Mallory	9-48300
CEF	500350

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Johnson/Evinrude models, please refer to the specific horsepower, cylinder count, and year range to ensure correct application.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Johnson/Evinrude	Various	20	2-Stroke	1985 & Up	393630
Johnson/Evinrude	Various	25	2-Stroke	1985 & Up	393630
Johnson/Evinrude	Commercial	25	2-Stroke	1998–2001	393630
Johnson/Evinrude	Various	30	2-Stroke	1980–1982	393630
Johnson/Evinrude	Various	30	2-Stroke	1983 & Up	393630	2-cylinder models
Johnson/Evinrude	Various	35	2-Stroke	1980–1982	393630
Johnson/Evinrude	Various	35	2-Stroke	1983 & Up	393630	2-cylinder models

Technical Specs

Product Type: Water Pump Impeller Kit with Housing
Installation: Direct OEM replacement
Housing Material: Metal/Aluminum (impeller: neoprene rubber)
Impeller Design: 6-blade
Other Technical Attributes: Complete kit with all necessary gaskets and hardware for installation

What’s in the Box

1 x Neoprene Impeller (395289)
1 x Impeller Key (330619)
1 x Gasket (325537)
1 x Wear Plate (328755)
1 x Pump (328751)
1 x Pump Housing (393632)
1 x Grommet (302497)
1 x Brass Bushing (328754)
4 x O-ring (311338 x 2 / For Bushing 301877 / 554545)
1 x Seal (328753)
6 x Washer (324960 / 318452)

Installation Notes

Disconnect the battery and remove the propeller for safety.
Drain the gearcase oil from the lower unit.
Remove the bolts securing the lower unit (gearcase) to the upper leg and carefully detach it.
Locate and unbolt the water pump housing.
Remove the old impeller, wear plate, gaskets, and seals. Clean all mating surfaces thoroughly.
Install the new wear plate, gasket, and impeller key.
Slide the new impeller onto the driveshaft, rotating it in the correct direction.
Install the new housing, seals, and hardware included in the kit, ensuring proper alignment.
Torque all bolts to the manufacturer's specified values.
Re-install the lower unit, refill the gearcase oil, and re-connect the battery before testing.

Troubleshooting & FAQ

How do I know if this kit fits my specific engine model?

This kit is designed for a wide range of Johnson/Evinrude 20-35 HP 2-stroke outboards. The best way to confirm is by checking your engine's model number and year against the compatibility table provided on this page. If you are unsure, cross-reference your existing OEM part number with 393630.

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 alerts or steam, and a decrease in overall engine performance. A brittle, cracked, or worn impeller is a clear indicator it needs replacement.

How often should the water pump impeller be replaced?

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

Is this kit difficult to install myself?

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

Is there a difference in performance between this kit and the OEM version?

This aftermarket kit is manufactured to meet or exceed original equipment specifications. The materials and design are engineered for comparable cooling performance and durability under normal marine operating conditions.

Why does the kit include multiple O-rings and washers?

This kit is designed to cover multiple engine variations over a long production run. Different models may use slightly different O-rings or washer configurations. Use the components that match the parts you are removing from your original pump assembly.

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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