277181 Water Pump Impeller for Evinrude Johnson 3HP 4HP 5HP 5.5HP 6HP 7.5HP | JLM Marine

Water Pump Impeller 277181 – Fits Evinrude Johnson 3HP 4HP 5HP 5.5HP 6HP 7.5HP Outboard Motors

This aftermarket water pump impeller is designed for Evinrude Johnson outboard motors ranging from 3HP to 7.5HP, manufactured between 1952 and 1983. It provides reliable cooling system performance for a wide range of classic Johnson and Evinrude models, ensuring your engine operates at optimal temperatures.

This impeller directly replaces OEM part numbers 277181 and 434424, as well as aftermarket equivalents including Sierra 18-3001 and CEF 500350. Engineered with high-performance neoprene rubber and a brass insert, it delivers durability and long-lasting performance in marine environments.

• Constructed from neoprene rubber and brass for corrosion resistance and durability
• Features 6 flexible blades for efficient water flow
• Includes impeller with key/pin for easy installation

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 × Outboard Rubber Impeller with Key / Pin

Installation Guide

1. Disconnect the fuel line and remove the lower unit from the outboard motor following your engine's service manual.
2. Remove the water pump housing and locate the old impeller inside the pump body.
3. Carefully extract the old impeller, noting the direction of the blade rotation. Remove the old key/pin from the driveshaft.
4. Clean the pump housing and driveshaft thoroughly, removing any debris, corrosion, or old gasket material.
5. Lubricate the new impeller blades with water pump grease or glycerin to ease installation and protect the rubber.
6. Insert the new key/pin into the driveshaft slot, ensuring it is seated properly.
7. Align the impeller keyway with the key/pin and slide the impeller onto the driveshaft. Rotate the blades in the correct direction (typically counterclockwise when viewed from above).
8. Install a new gasket on the pump housing and carefully position the housing over the impeller.
9. Secure the housing with the original bolts, tightening in a crisscross pattern to the manufacturer's torque specifications.
10. Reinstall the lower unit onto the outboard motor, ensuring all fasteners are properly torqued.
11. Reconnect the fuel line and perform a water flow test by running the engine with the motor submerged or using flushing muffs.
12. Check for consistent water discharge from the tell-tale hole, confirming proper impeller function.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my engine?
A: Cross-reference your engine's horsepower and year range with the compatibility table above. Verify that your original impeller matches the dimensions listed (69 mm diameter, 6 blades, 11 mm shaft). If your engine uses OEM part numbers 277181 or 434424, this impeller is the correct replacement.

Q: How often should I replace my water pump impeller?
A: Most manufacturers recommend replacing the impeller every 2–3 years or 200–300 hours of operation, whichever comes first. If you notice reduced cooling efficiency, overheating, or visible blade damage during inspection, replace it immediately regardless of time elapsed.

Q: What are the signs of a failing impeller?
A: Common symptoms include weak or no water flow from the tell-tale (indicator) stream, engine overheating, steam from the engine, or an audible high-temperature alarm. Inspect the impeller if any of these occur.

Q: Will this impeller fit 4HP models from 1973–1983?
A: Yes, but only for water pumps using 1 water tube. Some 4HP models in this year range may have different water pump configurations, so verify your pump design before ordering.

Q: Should I lubricate the impeller before installation?
A: Absolutely. Coat the impeller blades with water pump grease, glycerin, or a silicone-based lubricant before installation. This prevents the rubber from tearing during the first dry start and extends impeller life.

Q: Is this an OEM or aftermarket impeller?
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.