Water Pump Impeller Kit – Fits Mercury Marine 40-300 HP (Replaces 47-43026T06, 8M0100526)

Water Pump Impeller Kit – Fits Mercury Marine 40-300 HP (Replaces 47-43026T06, 8M0100526)

This water pump impeller service kit provides a reliable solution for maintaining the cooling system on a wide range of Mercury Marine outboard engines. It is designed for various 4-stroke and 2-stroke models from 40 HP to 300 HP, as well as Alpha I Gen II sterndrive applications.

As a direct replacement for multiple OEM and aftermarket part numbers, this kit ensures broad compatibility and restores performance for proper engine cooling.

• Complete Assembly: The kit includes the impeller, housing, face plate, gaskets, and seals required for a comprehensive service.
• Installation: Designed as a direct-fit replacement for the original OEM components, facilitating a straightforward installation.
• Function: Restores the water circulation system to prevent engine overheating and ensure optimal performance.

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 Impeller
• 1 x Impeller Key
• 1 x Face Plate
• 1 x Face Seal (26-816575A2)
• 2 x Impeller Gasket (27-817277)
• 1 x Impeller Gasket (27-430331)
• 1 x Seal Ring Gasket (26-45577)
• 2 x O-Ring (25-21836)
• 1 x Housing

Installation Guide

1. Secure the engine and disconnect the battery. Place the lower unit in a suitable position for service.
2. Remove the gearcase (lower unit) from the outboard motor by unfastening the mounting bolts.
3. Unscrew the bolts securing the water pump housing and lift it off the driveshaft.
4. Remove the old impeller, wear plate, gaskets, and seals. Take note of the original parts' orientation.
5. Thoroughly clean the mating surfaces to ensure a proper seal with the new gaskets.
6. Install the new gaskets and wear plate. Slide the new impeller onto the driveshaft, turning it clockwise to seat the vanes.
7. Apply a light coat of marine grease to the inside of the new housing and install it over the impeller.
8. Secure the housing with the bolts, tightening them to the torque specified in your service manual.
9. Reinstall the lower unit, ensuring the driveshaft and water tube are correctly aligned.
10. Once assembled, start the engine using a water supply (flushing muffs) to verify proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I know if this kit fits my Mercury engine?
This kit is designed for a wide array of Mercury outboards (40-300 HP) and Alpha I Gen II sterndrives. To confirm fitment, please refer to the "Compatible Engine Models" table and match your engine's model and serial number range. The most reliable method is to cross-reference the OEM part number (e.g., 47-43026T06) with the one listed in your engine's service manual.

What are the signs of a failing water pump impeller?
Common symptoms include a weak or intermittent water stream from the "telltale" cooling outlet, engine overheating alarms, or steam from the exhaust. A damaged impeller cannot provide sufficient water flow to cool the engine, leading to poor performance and potential damage.

How often should the water pump impeller be replaced?
As a critical maintenance component, the impeller should be inspected annually. It is recommended to replace it every 1-2 years or every 100-200 hours of operation, whichever comes first. More frequent replacement may be necessary if operating in saltwater or sandy/murky conditions.

Does this kit include the housing?
Yes, this is a complete service kit. It includes the water pump housing, impeller, wear plate, key, gaskets, o-rings, and seals necessary for a full replacement.

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.