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

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

This water pump impeller repair kit is designed for a wide range of Mercury/Mariner 2-stroke and 4-stroke outboards from 40 to 250 HP, including Verado models with 4.80" diameter torpedo gearcases. It is also compatible with MerCruiser Alpha One Generation 2 stern drives (serial number 0D469859 and above).

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 8M0100526, 47-43026Q06, Sierra 18-3265, and others, ensuring a precise fit and restoring cooling system performance.

• Engineered for direct replacement, simplifying installation.
• Features a high-performance neoprene rubber impeller and a durable, corrosion-resistant metal alloy housing.
• This complete kit contains the impeller, wear plate, gaskets, seals, and all necessary hardware for a full service.

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 Neoprene Impeller
• 1 x Wear Plate
• 1 x Gasket (impeller plate to cover)
• 1 x Gasket (gearcase cover)
• 1 x Key
• 1 x Oil Seal
• 2 x O-ring
• 1 x Grommet
• 2 x Washer

Installation Guide

Professional installation is recommended. The following are general steps for reference:

1. Prepare the Engine: Disconnect the battery and shift the outboard into the neutral position.
2. Remove Lower Unit: Unbolt and remove the lower unit (gearcase) from the engine's midsection. Be prepared for it to be heavy.
3. Access the Water Pump: With the lower unit on a workbench, locate and remove the screws holding the water pump housing cover.
4. Remove Old Components: Carefully lift off the housing to expose the old impeller. Take note of the blade orientation before removing the impeller, key, wear plate, gaskets, and seals.
5. Clean Surfaces: Thoroughly clean all mating surfaces. Remove any old gasket material, sealant, or corrosion to ensure a proper seal.
6. Install New Components: Install the new gaskets and the wear plate. Apply a light coat of marine grease to the inside of the new housing.
7. Install New Impeller: Slide the new key into the driveshaft and then install the new impeller. Turn the driveshaft clockwise while pushing down on the housing to correctly seat the impeller blades.
8. Secure Housing: Fasten the water pump housing with the original screws, tightening them to the torque specified by the manufacturer.
9. Reinstall Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube align correctly. Secure it with the mounting bolts.
10. Final Check: Reconnect the battery. Start the engine using a water supply (flushing muffs) and check for a strong, steady stream from the telltale port and for any leaks around the gearcase.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific engine model?

A: Check the "Compatible Engine Models" table and the "Part Number Cross-Reference" on this page. For Mercury and MerCruiser engines, it is crucial to verify your engine's serial number against the listed ranges. The guide linked in the compatibility section can help you locate your serial number.

Q: What are the signs of a failing water pump impeller?

A: Common signs include a weak or non-existent water stream from the "telltale" port, engine overheating alarms, and reduced engine performance. A visible inspection of your old impeller may also reveal cracked, stiff, or worn-down rubber blades.

Q: How often should the water pump impeller be replaced?

A: For preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years. Replacement frequency depends on usage hours and operating conditions (e.g., saltwater and sandy/silty water cause more wear).

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.