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

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

This water pump impeller is designed for a range of Johnson and Evinrude 2-stroke outboard engines, covering models from 3 HP to 7.5 HP manufactured between 1952 and 1983. It serves as a crucial component for maintaining proper engine cooling.

This is a direct aftermarket replacement for several OEM and other aftermarket part numbers, ensuring broad compatibility for the specified engine models.

• Core Component: Includes one 6-blade neoprene rubber impeller.
• Direct Fit: Engineered to match OEM specifications for reliable installation and performance.
• Application: For Johnson/Evinrude 2-stroke outboards from 3 HP to 7.5 HP.

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)

Installation Guide

1. Disconnect Power: Disconnect the spark plug wires and battery to prevent accidental starting.
2. Drain Gear Oil: Place a drain pan under the lower unit and remove the drain/fill screws to drain the gearcase oil.
3. Remove Lower Unit: Remove the bolts securing the lower unit (gearcase) to the engine's midsection. Note any hidden bolts under the trim tab.
4. Access Impeller: Carefully lower the gearcase. The driveshaft will come with it. The water pump housing is located on top of the gearcase.
5. Open Housing: Remove the bolts securing the water pump housing cover to access the impeller.
6. Remove Old Impeller: Slide the old impeller off the driveshaft. You may need to remove a key or pin first.
7. Clean & Inspect: Clean any gasket residue, salt, or corrosion from the housing and wear plate. Inspect them for deep scoring or damage.
8. Install New Impeller: Lightly lubricate the new impeller and the inside of the housing with marine grease. Slide the new impeller onto the driveshaft while turning the shaft clockwise to set the vanes in the correct direction.
9. Reassemble Pump: Reinstall the housing and torque its bolts to the manufacturer's specification.
10. Reattach Lower Unit: Guide the driveshaft back into place and reattach the lower unit to the engine. Tighten all bolts securely.
11. Refill Gear Oil: Refill the gearcase with the correct type and amount of marine gear lubricant.
12. Test Operation: Reconnect the battery. Start the engine in a water supply (using a test tank or "muffs") and confirm a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my Johnson/Evinrude engine?
A: First, check the "Compatible Engine Models" table to see if your engine's horsepower and year range are listed. This impeller is a direct replacement for Johnson/Evinrude part numbers 277181 and 434424. Verifying these details ensures correct fitment.

Q: What are signs my water pump impeller is failing?
A: The most common signs are the engine overheating, a weak or non-existent water stream from the "tell-tale" cooling outlet, or a high-pitched sound from the pump area. Upon inspection, a failing impeller may have cracked, brittle, or missing vanes.

Q: How often should I replace the water pump impeller?
A: As a preventative maintenance measure, it is recommended to replace the impeller every 1-2 years or every 100-200 hours of operation. More frequent replacement may be necessary if you operate in silty, sandy, or saltwater conditions.

Q: OEM vs. Aftermarket?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.