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

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

This water pump impeller repair kit is designed for a wide range of Mercury/Mariner outboards from 40 to 250 HP (both 2-stroke and 4-stroke models, from the 1990s to present) and MerCruiser Alpha One Generation II stern drives with serial numbers 0D469859 and above. It provides all necessary components for a complete and reliable water pump service.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury/Quicksilver 8M0100526 and 47-43026Q06, ensuring compatibility and performance.

• Installation: Direct replacement for a straightforward installation.
• Complete Kit: Includes a new impeller, wear plate, gaskets, seals, and o-rings for a full rebuild.
• Performance: Designed for durability to provide higher flow rates and restore cooling efficiency.

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

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (8M0025709)
• 1 x Impeller Drive Key (8M0032833)
• 1 x Water Pump Faceplate (8172761)
• 1 x Faceplate Gasket (8M0050720)
• 1 x Water Pump Gasket (8172771)
• 1 x Face Seal (8M2014338)
• 1 x Quad Ring (455771)
• 1 x O-ring (0.921 in. x 0.139 in.) (90196)
• 2 x O-ring (0.796 in. x 0.139 in.) (21836)
• 2 x Drain Plug Seal (830749)
• 1 x Face Seal Setting Tool (818769)

Installation Guide

For a successful installation, please follow these general steps. Professional installation is highly recommended.

1. Disconnect Power: Disconnect the battery cables to prevent any electrical accidents.
2. Position the Engine: Trim the outboard to the full-down (vertical) position.
3. Drain Gearcase Lube: Place a drain pan under the lower unit and remove the upper and lower gear lube drain screws to drain the lubricant.
4. Remove Lower Unit: Remove the bolts securing the lower unit (gearcase) to the engine. The unit should slide down and off. You may need to disconnect the speedometer tube.
5. Access the Water Pump: With the lower unit removed, locate the water pump housing on top of the gearcase. Remove the bolts securing the pump cover.
6. Inspect and Remove Old Parts: Remove the old cover, gaskets, wear plate, and impeller. Note the rotational direction of the old impeller fins. Clean all gasket surfaces thoroughly.
7. Install New Impeller: Slide the new wear plate and gasket into place. Install the new impeller drive key. Apply a light coat of lubricant to the inside of the pump housing and install the new impeller by pushing down while turning the driveshaft in the direction of engine rotation.
8. Install New Seals: Use the included gaskets and seals to reassemble the housing. The included tool helps properly set the face seal.
9. Reassemble Housing: Securely tighten the water pump housing bolts to the manufacturer's specified torque.
10. Reinstall Lower Unit: Carefully guide the lower unit back into position, ensuring the driveshaft, water tube, and shift shaft align correctly. Secure it with the bolts, tightening to the proper torque.
11. Refill Gearcase Lube: Fill the gearcase with fresh lubricant from the bottom hole until it seeps out the top vent hole. Reinstall both drain screws with new gaskets.
12. Test Operation: With the engine in water or a test tank, start it and check for a steady stream of water from the tell-tale outlet to confirm the pump is working correctly.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my engine?
A: The best way is to match your engine's serial number to the ranges listed in the "Compatible Engine Models" table above. If your serial number is not available, you can cross-reference the part number from your old water pump or service manual with our "Part Number Cross-Reference" table.

Q: What are the signs my water pump impeller needs to be replaced?
A: Common signs include the engine running hotter than normal, a weak or non-existent water stream from the tell-tale outlet, or a high-temperature alarm. Brittle, cracked, or discolored impeller vanes found during inspection also indicate it's time for a replacement.

Q: How often should I replace my water pump impeller?
A: For preventative maintenance, we recommend replacing the impeller every 1-2 years or every 100-200 hours of operation. Service intervals should be shorter if you frequently operate in saltwater or sandy/silty water.

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.