Water Pump Impeller Kit – Fits Mercury 135/150 HP EFI 4-Stroke (Replaces 46-8M0061040)

Water Pump Impeller Kit – Fits Mercury 135/150 HP EFI 4-Stroke (Replaces 46-8M0061040)

This water pump impeller service kit is designed for Mercury/Mariner 135–150 HP 4-Stroke outboard engines. It provides a reliable solution for maintaining your engine’s cooling system, ensuring optimal performance and preventing overheating.

This kit is a direct replacement for Mercury part number 46-8M0061040.

• Engineered for Mercury and Mariner FourStroke EFI models.
• Includes all essential components for a standard water pump rebuild.
• Installation is a direct replacement for the original housing.

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

This kit includes the following components:

• Impeller
• Gaskets
• Wear Plate
• Key Way
• Shaft Seal

Installation Guide

1. Disconnect Power: Disconnect the battery and shift the outboard into neutral.
2. Access Lower Unit: Remove the bolts securing the lower unit (gearcase) to the upper driveshaft housing.
3. Remove Lower Unit: Carefully lower the gearcase away from the engine.
4. Open Pump Housing: Unscrew the bolts on the water pump housing cover to access the impeller.
5. Inspect and Remove Old Parts: Take note of the old parts' orientation. Remove the old impeller, wear plate, and gaskets.
6. Clean Surfaces: Thoroughly clean the housing interior and mating surfaces, removing any old gasket material or debris.
7. Install New Components: Install the new wear plate, gaskets, and key way. Slide the new impeller onto the driveshaft, rotating it in the correct direction to bend the vanes.
8. Reassemble Housing: Secure the water pump cover, applying a light coat of marine grease to the bolts if necessary.
9. Reattach Lower Unit: Carefully align the driveshaft and water tube, then bolt the lower unit back into place.
10. Test Operation: Reconnect the battery, start the engine in the water or with a flush attachment, and verify a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?

Check the 'Compatible Engine Models' table and verify your model and horsepower. For Mercury engines, you can use the provided serial number guide to find your exact model details. Always verify that your existing part number matches one of the cross-reference numbers, such as 46-8M0061040.

What are the signs of a failing water pump impeller?

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

How often should I replace the water pump impeller?

To prevent engine damage from overheating, it is recommended to inspect the impeller annually and replace it every 1 to 2 years or every 100-200 hours of use. This interval should be shorter if operating frequently in saltwater or silty/sandy conditions.

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.