Water Pump Impeller – Fits Mercury/Mariner 15-50 HP (Replaces 47-8508910, 0755466)

Water Pump Impeller – Fits Mercury/Mariner 15-50 HP (Replaces 47-8508910, 0755466)

This water pump impeller is designed for a wide range of Mercury/Mariner 15-50 HP 2-stroke and 4-stroke outboards (1974-2006), including XD, Bigfoot, SeaPro, and Mara models. It provides a reliable, direct replacement for your original component to ensure proper engine cooling.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 47-8508910, 47-85089-10, 8M0204712, 47-85089-3, 850893, 8M0024502; Force/OMC 0755466; Sierra 18-3057; Mallory Marine 9-45303; GLM 89640; and CEF 500315.

• Installation Type: Direct OEM Replacement
• Hub Design: Features a durable brass hub with a drive key connection.
• Package Includes: 1x Impeller, 1x Drive Key

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 Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 47-8508910)
• 1 x Drive Key

Explosion Diagram

Installation Guide

1. Safety First: Disconnect the engine's battery before starting work.
2. Access the Lower Unit: Remove the bolts securing the lower unit (gearcase) and carefully separate it from the upper housing.
3. Open the Pump Housing: Locate the water pump assembly on top of the lower unit and remove its cover bolts.
4. Remove Old Impeller: Lift the housing cover and slide the old impeller off the drive shaft. Note the orientation of the blades.
5. Inspect and Clean: Clean the inside of the pump housing and inspect it for scoring, corrosion, or warping. Replace the housing if significant wear is found.
6. Install New Impeller: Insert the new drive key into the driveshaft. Slide the new impeller onto the shaft while turning it in the direction of engine rotation to correctly seat the blades.
7. Reassemble: Re-install the pump housing, ensuring gaskets are aligned. Torque the bolts to the manufacturer's specified value.
8. Attach Lower Unit: Reattach the lower unit to the engine, making sure the driveshaft and water tube align correctly.
9. Test Operation: Reconnect the battery, start the engine using a water supply (flusher or in water), and confirm a steady stream of water exits the tell-tale port.

Troubleshooting & FAQ

How do I confirm this impeller fits my engine?
Verify your engine's model, horsepower (HP), and year of manufacture against the detailed "Compatible Engine Models" table above. For Mercury owners, our Mercury Serial Number Guide can help you accurately identify your engine to ensure compatibility.

What are the signs of a failing water pump impeller?
The most common symptoms are engine overheating at idle or low speeds, and a weak, sputtering, or nonexistent water stream from the engine's tell-tale outlet. Visual inspection may reveal cracked, brittle, or worn-down impeller blades.

How often should I replace the 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 operation. Replacement frequency should be increased if operating in sandy, silty, or saltwater conditions.

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.