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

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

This water pump impeller repair kit provides the necessary components to restore the cooling system on a wide range of Mercury/Mariner outboards and MerCruiser sterndrives. It is designed to fit 40–250HP, 2-Stroke & 4-Stroke outboards (1990–present) and MerCruiser Alpha One Generation 2 sterndrives (serial number 0D469859 and above).

Engineered as a direct replacement for multiple OEM part numbers, this kit ensures a precise fit and reliable performance. It is a cost-effective solution for routine maintenance or addressing cooling system failures.

• Installation Type: Direct replacement
• Housing Materials: Constructed with durable stainless steel and neoprene rubber
• Key Components: Includes impeller, gaskets, wear plate, and key for a complete 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.

Mercury/Mariner Outboards

MerCruiser Sterndrives

Technical Specifications

Package Contents

This kit includes the following components:

• 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)

Note: Some kit variations may also include a Wear Plate, O-Rings, a Grommet, and Washers.

Installation Guide

1. Safety First: Before starting, disconnect the battery and ensure the engine is turned off and cool.
2. Access the Lower Unit: Drain the gearcase oil. Remove the lower unit (gearcase) from the outboard by unbolting it from the engine leg.
3. Remove the Water Pump Housing: Locate the water pump assembly on top of the lower unit. Unscrew the bolts holding the pump cover in place and lift it off.
4. Inspect and Remove Old Parts: Take note of the old impeller's orientation. Remove the old impeller, gaskets, and wear plate, checking carefully for any debris or damage.
5. Clean Mating Surfaces: Thoroughly clean the surfaces of the pump housing and base to ensure a proper seal with the new gaskets.
6. Install New Components: Lightly lubricate the new impeller with a marine-safe lubricant. Install the new wear plate, gaskets, and impeller. Rotate the driveshaft clockwise while pushing down to seat the impeller blades correctly.
7. Reassemble the Pump: Reinstall the pump housing and torque the bolts to the manufacturer's specified value.
8. Reinstall Lower Unit: Reattach the lower unit to the outboard, ensuring the driveshaft and water tube align correctly. Refill the gearcase with fresh oil.
9. Test the System: Reconnect the battery. With the outboard in water, start the engine and verify that water is exiting the "tell-tale" outlet, indicating proper pump function.

Troubleshooting & FAQ

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

A: The best way is to match your engine's serial number and model year against the compatibility tables above. For Mercury/MerCruiser engines, use the provided serial number guide to find your details. Cross-referencing the OEM part number of your old impeller kit is also a reliable method.

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

A: The most common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the tell-tale outlet, and a melted or brittle appearance of the old impeller upon inspection.

Q: How often should I replace my water pump impeller?

A: For preventative maintenance, it is recommended to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can vary based on usage conditions (e.g., saltwater vs. freshwater).

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.