Water Pump Impeller Kit – Fits MerCruiser Alpha One Gen II (Replaces 47-43026Q06, 47-8M0100526)

Water Pump Impeller Kit – Fits MerCruiser Alpha One Gen II (Replaces 47-43026Q06, 47-8M0100526)

This water pump impeller service kit is designed for MerCruiser Alpha One Gen II sterndrives (serial numbers D469859 and above, from 1991 and newer). It provides the necessary components to restore the engine's cooling system for optimal performance and reliability.

This kit is a direct replacement for MerCruiser parts 47-43026Q06 and 47-8M0100526, Quicksilver 47-43026Q06 and 47-8M0100526, and Sierra 18-3214.

• Installation Location: Lower Unit/Sterndrive
• Compatible with specific MerCruiser sterndrives and Mercury outboards.
• Includes impeller, gaskets, o-ring, plate, and seals for a comprehensive 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.

Note: This impeller kit is also compatible with certain Mercury outboards.

Package Contents

• 1 x Impeller
• 1 x Face Seal
• 1 x Face Seal Setting Tool
• 1 x O-Ring
• 1 x Water Pump Base Plate
• 2 x Gaskets

Installation Guide

1. Safety First: Disconnect the battery before starting any work.
2. Drain Gear Lube: Place a drain pan under the lower unit and remove the upper and lower drain/vent screws to drain the gear lube completely.
3. Remove Lower Unit: Remove the bolts securing the sterndrive's lower unit. Carefully separate the lower unit from the upper housing.
4. Access the Pump: With the lower unit removed, locate and remove the bolts holding the water pump housing in place.
5. Inspect and Replace Impeller: Lift the housing to expose the impeller. Note the rotational direction of the old impeller's vanes before removing it. Clean the housing interior and install the new impeller.
6. Replace Seals and Gaskets: Carefully replace the gaskets, wear plate, and any seals included in your kit. Ensure all surfaces are clean and properly aligned.
7. Reassemble Pump Housing: Reinstall the water pump housing, ensuring the new gaskets are seated correctly. Torque the bolts to the manufacturer's specification.
8. Reinstall Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, water tube, and shift shaft align. Secure it with the bolts.
9. Refill Gear Lube: Pump fresh, manufacturer-recommended gear lube into the lower drain hole until it flows out of the upper vent hole. Reinstall both screws.
10. Test Operation: Reconnect the battery. Start the engine using a water supply (flushing muffs) and check for a steady stream of water from the tell-tale outlet. Check for leaks around the gearcase.

Troubleshooting & FAQ

How do I confirm this fits my Alpha One Gen II sterndrive?

This kit is specifically for MerCruiser Alpha One Gen II sterndrives with a serial number of D469859 and above, which corresponds to models made in 1991 and newer. Please verify your serial number before purchasing.

What are the signs of a bad water pump impeller?

Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet, and a dry, cracked, or brittle appearance of the impeller vanes upon inspection.

How often should I replace the impeller?

For preventative maintenance, it is recommended to replace your impeller every 100-200 hours of operation or every 1-2 years, whichever comes first. Service intervals should be shorter if you frequently operate in sandy, silty, or saltwater conditions.

Is this an OEM part?

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.