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

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

This water pump impeller kit is an aftermarket replacement compatible with a wide range of Mercury and Mariner outboards from 40 to 300 HP, covering both 2-Stroke and 4-Stroke models from 1996 to the present. It also fits MerCruiser Alpha One Gen II sterndrive units with serial numbers 0D469859 and higher.

This assembly is a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility and restoring proper engine cooling performance.

• Installation Type: Direct replacement for a straightforward installation.
• Performance: Designed for higher flow rates to deliver improved and reliable cooling.
• Complete Kit: Includes all necessary components for a full service, including the impeller, wear plate, housing, gaskets, and seals.

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 Sterndrive

Technical Specifications

Package Contents

• 1 x Impeller (47-43026T2)
• 1 x Impeller Key
• 2 x Impeller Gasket (27-817277)
• 1 x Face Seal (26-816575A2)
• 1 x Seal Ring Gasket (26-45577)
• 2 x O-Ring (25-21836)
• 1 x Face Plate
• 1 x Cover
• 1 x Washer
• 1 x Grommets

Installation Guide

1. Safety First: Disconnect the battery and remove the spark plug wires to prevent accidental starting.
2. Drop Lower Unit: Disconnect the shift linkage (if applicable) and remove the bolts securing the lower unit (gearcase). Carefully lower it from the outboard midsection.
3. Disassemble Pump: Place the lower unit on a workbench. Remove the bolts holding the water pump housing cover in place.
4. Remove Old Components: Lift off the housing and slide the old impeller off the driveshaft. Remove the impeller key, wear plate, and any old gaskets or seals.
5. Clean Surfaces: Thoroughly clean the mounting surfaces on the gearcase and the inside of the housing. Remove any old gasket material or corrosion.
6. Install New Parts: Place the new gaskets and wear plate onto the gearcase. Insert the new impeller key into the driveshaft.
7. Install New Impeller: Slide the new impeller onto the shaft while turning the driveshaft clockwise to bend the vanes in the correct direction. Apply a light coat of marine grease or soapy water to ease installation.
8. Reassemble Pump: Install the new housing and seals. Tighten the bolts to the manufacturer's recommended torque specifications.
9. Reinstall Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, water tube, and shift shaft align properly. Reinstall and tighten bolts.
10. Final Checks: Reconnect the shift linkage and battery. Start the engine using a water supply (flushing muffs) and confirm a steady stream from the tell-tale outlet.

Troubleshooting & FAQ

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

A: First, check the "Compatible Engine Models" table to see if your model, HP, and year range are listed. For Mercury/MerCruiser engines, it is critical to verify your serial number against the notes in the table. You can use the provided serial number guide to help locate it. Cross-referencing the OEM part number (e.g., 47-43026T06, 8M0100526) with your engine's service manual is the most reliable method.

Q: What are the signs that my water pump impeller is failing?

A: The most common symptoms are engine overheating, especially at idle or low speeds, a weak or intermittent water stream from the "tell-tale" outlet, or a low water pressure reading on your gauges. A brittle or cracked impeller discovered during inspection also requires immediate replacement.

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

A: As a general rule for preventative maintenance, it is highly recommended to replace the impeller every 1 to 2 years or every 100-200 hours of operation, whichever occurs first. This interval can be shorter if you frequently operate in sandy or 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.