Water Pump Impeller – Fits Johnson/Evinrude 35-55 HP (Replaces 377230, 777213, 777821)

$15.00

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Water Pump Impeller – Fits Johnson/Evinrude 35-55 HP (Replaces 377230, 777213, 777821) is backordered and will ship as soon as it is back in stock.

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Product Details

This aftermarket Water Pump Impeller – Fits Johnson/Evinrude 35-55 HP Outboards (Replaces 377230, 777213) is designed for a range of Johnson/Evinrude 2-Stroke outboard motors from 1958 to 1978, including models with 35, 40, 50, and 55 horsepower ratings.

It serves as a direct replacement for Johnson/Evinrude part numbers 377230, 777213, and 777821, as well as aftermarket equivalents Sierra 18-3083 and Mallory 9-45209.

Direct replacement simplifies installation in the water pump housing.
Engineered to be resistant to salt water immersion over extended periods.
Includes one high-quality neoprene rubber impeller.

Part Number Matrix

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

Brand	Part Number
Johnson/Evinrude	377230
Johnson/Evinrude	777213
Johnson/Evinrude	777821
Sierra	18-3083
Mallory	9-45209

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Johnson Outboards: This impeller is compatible with various 35, 40, 50, and 55 HP models manufactured between 1958 and 1978.

For Evinrude Outboards: This impeller is compatible with various 35, 40, 50, and 55 HP models manufactured between 1958 and 1978.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Johnson	Various	35	2-Stroke	1958–1959	377230
Johnson	Various	40	2-Stroke	1960–1970	377230
Johnson	Various	50	2-Stroke	1971–1978	377230
Johnson	Various	55	2-Stroke	1971–1978	377230
Evinrude	Various	35	2-Stroke	1958–1959	377230
Evinrude	Various	40	2-Stroke	1960–1970	377230
Evinrude	Various	50	2-Stroke	1971–1978	377230
Evinrude	Various	55	2-Stroke	1971–1978	377230

Technical Specs

Product Type: Water Pump Impeller
Installation: Direct replacement in water pump housing
Material: High-quality neoprene rubber with brass hub
Dimensions: External Diameter: 69.81 mm (2 3/4"), Internal Shaft Insert Diameter: 15.91 mm (5/8"), Height: 21.79 mm (55/64")
Durability: Resistant to salt water immersion over extended periods
Compatible Engines: Johnson/Evinrude 35-55 HP 2-Stroke outboards
Application: OEM replacement for cooling system water pump

What’s in the Box

1 x Water Pump Impeller (377230/777213)

Installation Notes

Disconnect the battery and remove the engine cover.
Drain the lower unit gear oil.
Remove the bolts securing the lower unit (gearcase) to the upper housing.
Carefully lower and remove the gearcase assembly.
Locate and unbolt the water pump housing.
Remove the old impeller, noting its rotational direction and the keyway position.
Clean the inside of the pump housing and inspect it for wear or damage.
Lightly grease the new impeller and the inside of the housing with a marine-safe lubricant.
Install the new impeller, turning the driveshaft in its normal rotational direction to correctly set the vanes.
Reassemble the water pump housing, lower unit, and reconnect all components in reverse order.
Refill the gearcase with the correct grade of oil.
Test the engine in water or with a flush attachment to confirm proper cooling system operation.

Troubleshooting & FAQ

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

This impeller fits a wide range of Johnson and Evinrude 2-stroke outboards from 35 HP to 55 HP, manufactured between 1958 and 1978. Always verify your engine's original part number against the cross-reference list (e.g., 377230, 777213) and check the provided dimensions before ordering.

What are the signs of a failing water pump impeller?

Common signs include a weak or non-existent water stream from the engine's "tell-tale" outlet, engine overheating alarms, and reduced engine performance. We recommend inspecting the impeller annually.

What is the recommended replacement interval?

For most recreational boaters, replace the impeller every one to two years or every 100-200 hours of operation. For heavy or commercial use, annual replacement is strongly advised to prevent engine damage.

Is any special tool required for installation?

Standard mechanic's tools like a socket set and screwdrivers are usually sufficient. A gear oil pump will be needed to refill the lower unit. No highly specialized tools are typically required for an impeller replacement.

What’s the difference between part number 377230 and 777213?

Part number 777213 is often cited as a supersession or direct replacement for 377230. For the compatible engine models listed, they are functionally interchangeable. This aftermarket part is designed to replace both.

Can I run the engine out of water after installing the new impeller?

No. Never run the engine without a proper water supply. "Dry running" the pump, even for a few seconds, will instantly destroy the new neoprene impeller. Always use a flush attachment ("muffs") or test the boat in the water.

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

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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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