Water Pump Impeller – Fits Johnson/Evinrude 3-7.5 HP 2-Stroke (Replaces 277181, 434424)

$14.50

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Water Pump Impeller – Fits Johnson/Evinrude 3-7.5 HP 2-Stroke (Replaces 277181, 434424) 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 aftermarket Water Pump Impeller is designed for a range of Johnson/Evinrude 2-stroke outboard engines, including 3 HP (1952–1978), 4 HP (1969–1983), 5 HP (1965–1968), 5.5 HP (1954–1964), 6 HP (1952–1978), and 7.5 HP (1954–1958) models.

It serves as a direct interchange for Sierra part 18-3001, Johnson/Evinrude parts 277181, 434424, 0277181, 0434424, and 0777819, and Mallory part 9-45216.

Constructed from durable neoprene rubber for reliable performance.
Engineered with 6 blades for efficient water cooling.
Installation should be performed following the engine's service manual.

Part Number Matrix

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

Brand	Part Number
Sierra	18-3001
Johnson/Evinrude	277181 / 434424 / 0277181 / 0434424 / 0777819
Mallory	9-45216

Engine & Model Compatibility

Confirm your engine model/year in the table below.

The following table lists compatible Johnson/Evinrude models. Please check the horsepower, year range, and any specific notes for your engine.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Johnson/Evinrude	Various	3	2-Stroke	1952–1978	277181/434424
Johnson/Evinrude	Various	4	2-Stroke	1969–1972	277181/434424
Johnson/Evinrude	Various	4	2-Stroke	1973–1983	277181/434424	For water pumps using 1 water tube, 110 gearcase
Johnson/Evinrude	Various	5	2-Stroke	1965–1968	277181/434424
Johnson/Evinrude	Various	5.5	2-Stroke	1954–1964	277181/434424
Johnson/Evinrude	Various	6	2-Stroke	1952–1978	277181/434424
Johnson/Evinrude	Various	7.5	2-Stroke	1954–1958	277181/434424

Technical Specs

Product Type: Water Pump Impeller
Number of Blades: 6
Material: Neoprene rubber
Depth/Height: 12.7 mm (0.5 in)
Outer Diameter: 68.46–69.34 mm (2.69–2.73 in)
Inner Hub Diameter: 10.97–11.01 mm (0.43 in)
Weight: 41 g (1.45 oz)

What’s in the Box

1 x Water Pump Impeller (Replaces 277181/434424)

Installation Notes

Disconnect the engine's battery and shift the outboard into neutral.
Remove the lower unit (gearcase) bolts and carefully lower the unit to access the water pump.
Unbolt and remove the water pump housing cover. Note the rotational direction of the old impeller's blades.
Remove the old impeller, key, and gaskets. Thoroughly clean all mating surfaces.
Install the new gasket and insert the drive key. Slide the new impeller on, turning it in the correct rotational direction to fold the blades properly.
Re-install the water pump housing and tighten bolts to the manufacturer's specified torque.
Re-attach the lower unit to the engine, ensuring the water tube and driveshaft are aligned correctly.
Once fully 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?

First, check the Engine & Model Compatibility table to ensure your Johnson/Evinrude model, horsepower, and year range are listed. Second, cross-reference your existing part number with the equivalents in the Part Number Matrix. If both match, it should fit.

What are the signs of a failing water pump impeller?

The most common signs of a worn or damaged impeller are a weak or non-existent water stream from the engine's "telltale" indicator, an engine overheating alarm, or steam from the exhaust. Reduced cooling performance can cause severe engine damage.

How often should I replace my impeller?

For preventative maintenance, it is recommended to replace your impeller every 1 to 2 years or every 100-200 hours of use, whichever comes first. This schedule applies even if the impeller appears to be in good condition.

Is this an OEM part or 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.

How fast is shipping and what does it cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is the warranty and return policy?

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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