Heavy Duty Sea Water Pump Impeller Kit – Fits Mercury/MerCruiser V6 & V8 (Replaces 47-8M0137219)

Heavy Duty Sea Water Pump Impeller Kit – Fits Mercury/MerCruiser V6 & V8 (Replaces 47-8M0137219)

This heavy-duty sea water pump impeller kit is engineered for specific Mercury/MerCruiser V6 & V8 engines (305, 350, 496 & 502 CID) manufactured from 2000 onwards. It is designed exclusively for models equipped with brass sea water pumps and is not suitable for 4.5L & 6.2L engines.

This kit serves as a direct replacement for Mercury part numbers 47-8M0137219 and 47-8M0120891, providing a reliable solution for maintaining your engine's cooling system.

• Engineered as a heavy-duty replacement for worn original pump housings.
• The kit includes a precision-formed O-ring, a heavy-duty impeller, and an overmolded inner wear plate.
• Features a durable 8-blade impeller design for consistent cooling 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 Formed O-Ring (8M2021987)
• 1 x 0.030 inch Shorter Heavy Duty Impeller (8M0103389)
• 1 x Overmolded Inner Wear Plate (8M0072979)

Installation Guide

1. Shut off the engine, allow it to cool completely, and disconnect the negative battery terminal.
2. Close the sea cock (water intake valve) to prevent water from entering the vessel.
3. Locate the sea water pump, which is typically mounted on the engine.
4. Place a drain pan under the pump and carefully remove the intake and outlet hoses.
5. Unscrew the bolts securing the pump cover and gently pry the cover off.
6. Take note of the blade direction of the old impeller before removing it from the housing.
7. Remove the old gasket or O-ring and thoroughly clean the interior surfaces of the housing and cover.
8. Install the new impeller by squeezing the blades together and pushing it into the housing, ensuring the blades are oriented correctly for your engine's rotation.
9. Seat the new O-ring in its groove and reinstall the pump cover, tightening the bolts evenly in a crisscross pattern.
10. Reconnect the hoses, open the sea cock, and reconnect the battery.
11. After starting the engine, check for proper water flow and inspect for any leaks.

Troubleshooting & FAQ

Q: How do I confirm this impeller kit fits my MerCruiser engine?

A: This kit is designed for MerCruiser V6 & V8 engines (305, 350, 496, 502 CID) from 2000 and newer that use a brass sea water pump. It is not compatible with 4.5L or 6.2L models. Please verify your engine model and year against the "Compatible Engine Models" table and ensure your pump housing is brass.

Q: What's the difference between this impeller and the standard OEM one?

A: This is a heavy-duty replacement featuring an impeller that is 0.030 inches shorter and an overmolded inner wear plate. These design enhancements are intended to provide a better seal and increased durability, especially in housings that may have minor wear.

Q: What are the signs that my sea water pump impeller needs to be replaced?

A: Common signs of a failing impeller include the engine overheating at idle or low speeds, a reduced flow of water from the exhaust, or visible cracks and missing blades on the old impeller upon inspection.

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

A: For preventative maintenance, it is recommended to inspect your impeller annually and replace it every 1-2 years, or more frequently if you 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.