Water Pump Impeller Kit – Fits Mercury/Mariner 40–250HP & MerCruiser Alpha One Gen 2 (Replaces 47-43026Q06, 8M0100526)

Water Pump Impeller Kit – Fits Mercury/Mariner 40–250HP & MerCruiser Alpha One Gen 2

This water pump impeller service kit is designed for a wide range of Mercury/Mariner outboards and MerCruiser Alpha One Gen 2 stern drives. It provides the necessary components to restore your engine's cooling system performance, helping to prevent overheating and ensure reliability.

This kit is a direct replacement for multiple OEM and aftermarket part numbers, fitting various 2-stroke and 4-stroke outboard models from the late 1990s onward, as well as sterndrives manufactured since 1991.

• Installation Type: Direct replacement for original equipment.
• Core Components: Includes a durable neoprene impeller, stainless steel wear plate, and all necessary gaskets and seals for a complete service.
• Gasket Material: Features non-asbestos gaskets for modern, safe engine maintenance.

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.

Mercury/Mariner Outboards

MerCruiser Stern Drives

Technical Specifications

Package Contents

• 1 x Impeller (47-43026Q02)
• 1 x Impeller Plate (817276)
• 1 x Impeller Key (28-8M0032833)
• 1 x Seal Ring Gasket (26-45577)
• 1 x Impeller Gasket (27-817277)
• 2 x O-ring (25-21836)
• 1 x Oil Seal (26-816575A2)
• 2 x Drain Screw Gasket (26-830749)
• 1 x Face Seal Setting Tool (818769)

Installation Guide

1. Disconnect the battery and ensure the engine is off and cool.
2. Position the outboard or sterndrive to allow for lower unit removal. Using a stand is recommended.
3. Drain the gearcase oil into a suitable container.
4. Remove the bolts securing the lower unit (gearcase) and carefully detach it from the engine.
5. Unbolt and lift the water pump housing to expose the impeller.
6. Remove the old impeller, wear plate, key, gaskets, and seals. Note their orientation.
7. Thoroughly clean the housing interior and all mating surfaces.
8. Install the new gaskets, wear plate, and impeller with its key. Lubricate the impeller and housing with a light coat of marine grease.
9. Re-install the water pump housing and torque the bolts to the manufacturer's specified value.
10. Carefully re-attach the lower unit to the engine, ensuring the driveshaft and shift shaft align correctly.
11. Refill the gearcase with the correct type and amount of marine gear lube.
12. Once assembled, connect a water supply (flushing muffs) to the lower unit and test the engine at idle to confirm a strong, steady water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my MerCruiser Alpha One Gen 2?
This kit is compatible with MerCruiser Alpha One Gen 2 drives manufactured from 1991 onwards. To be certain, always check that your existing part number matches one of the numbers in our cross-reference list, such as 47-43026Q06 or 8M0100526.

What are the signs that my water pump impeller is failing?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent "telltale" water stream, a high temperature alarm sounding, or, in severe cases, a melted water pump housing. Proactive replacement is the best prevention.

How often should I replace the impeller?
For preventative maintenance, we recommend replacing your impeller every 1-2 years or every 100-200 hours of use. More frequent changes may be necessary if you operate in silty, sandy, 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.