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

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

This water pump impeller is designed for select Johnson/Evinrude 2-stroke outboard motors ranging from 3 HP to 7.5 HP manufactured between 1952 and 1983. It serves as a crucial component of the engine's cooling system, ensuring reliable water circulation to prevent overheating.

This component is a direct replacement for Johnson/Evinrude part numbers 277181, 434424, 0277181, 0434424, and 0777819. It also cross-references with Sierra 18-3001, Mallory 9-45216 / 9-45216-10, GLM 89580, and CEF 500350.

• Material: Durable, high-quality neoprene rubber for reliable performance.
• Blades: Features a 6-blade design for optimal water flow.
• Installation: Replace per your engine's original service manual specifications.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson/Evinrude Serial Number Guide.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 277181/434424)
• 1 x Key/Pin (Package contents may vary. Some brands include the key while others sell it separately. Please verify before purchase.)

Installation Guide

Professional installation is recommended. Always follow the procedures outlined in your engine's official service manual.

1. Disconnect the battery and shift linkage before beginning.
2. Carefully unbolt and remove the lower unit (gearcase) from the outboard's midsection.
3. Locate and unbolt the water pump housing cover to expose the impeller.
4. Remove the old impeller, taking note of the blade orientation. You may need to remove a key or pin from the driveshaft.
5. Thoroughly clean the inside of the pump housing and inspect it for scoring, warping, or cracks.
6. Lightly lubricate the new impeller and the inside of the housing with a suitable marine grease.
7. Install the new key/pin onto the driveshaft and slide the new impeller down, turning the driveshaft clockwise to correctly fold the blades.
8. Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
9. Reattach the lower unit to the outboard, ensuring the driveshaft, shift shaft, and water tube align correctly.
10. Reconnect the shift linkage and battery.
11. Start the engine using a flush attachment or in water to verify proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this impeller fits my engine?
First, check the "Compatible Engine Models" table to see if your model and year are listed. This part is specifically designed for Johnson/Evinrude 3 HP to 7.5 HP models from 1952-1983. For certain 4 HP models (1973-1983), it's important to confirm your water pump uses 1 water tube and is on a 110 gearcase. The most reliable method is to cross-reference your original OEM part number with the numbers provided in our list.

What are the signs of a failing water pump impeller?
Common signs of a worn or damaged impeller include a weak, inconsistent, or non-existent water stream from the "telltale" outlet, engine overheating alarms, or steam from the exhaust. A reduction in cooling performance can cause severe engine damage if not addressed.

How often should I replace the water pump impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use. The interval can vary based on operating conditions; engines used in saltwater or sandy/silty water may require more frequent replacement. Always refer to your engine's service manual for specific maintenance schedules.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.