Water Pump Repair Kit – Fits Mercury 175-300HP & 450R V6/V8 4-Stroke Outboards (Replaces 8M0205803, 8M0142980)

Water Pump Repair Kit – Fits Mercury 175-300HP & 450R V6/V8 4-Stroke Outboards

This water pump repair kit is designed for Mercury Marine 175-300HP 3.4L V6 and 4.6L V8 4-stroke outboards (2019 and newer, serial number 2B529482 and above), including 450R models.

It serves as a direct replacement for multiple OEM part numbers, ensuring a precise fit and reliable performance for your engine's cooling system.

• Installation Method: Direct replacement for a straightforward installation.
• Engine Compatibility: Specifically fits Mercury V6/V8 4-stroke outboards with serial number 2B529482 and above.
• Complete Kit: Includes the impeller, face plate, gaskets, seals, and installation tool for a comprehensive 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.

Technical Specifications

Package Contents

• 1 x Water Pump Gasket (8M0205803)
• 1 x Face Plate (8M0205803)
• 1 x Face Plate Gasket (8M0205803)
• 1 x Impeller Key (8M0205803)
• 1 x Impeller (8M0205803)
• 1 x Face Seal (8M0205803)
• 1 x Drain Plug Seal (8M0205803)
• 1 x Water Pump Gasket (8M0205803)
• 1 x O-Ring (8M0205803)
• 1 x Actuator Seal (8M0205803)
• 1 x Face Seal Tool (8M0205803)

Installation Guide

1. Disconnect the negative battery cable to prevent accidental starting. Place the engine in neutral.
2. Remove the lower unit (gearcase) from the outboard by unbolting it from the midsection. This may require an assistant.
3. Place the lower unit on a workbench and remove the bolts securing the water pump housing.
4. Slide the old housing, impeller, gaskets, and wear plate off the driveshaft. Note the orientation of the old impeller blades.
5. Clean all mating surfaces of any old gasket material or debris.
6. Install the new components in reverse order: gaskets, wear plate, impeller key, and impeller. Lightly grease the new impeller and slide it on while turning the driveshaft clockwise.
7. Install the new face seal, tool, plate gaskets, and housing. Ensure all seals are properly seated.
8. Torque the housing bolts to the manufacturer's recommended specification.
9. Reinstall the lower unit onto the outboard, making sure the driveshaft and water tube align correctly.
10. Reconnect the battery. Start the engine using a water source (flushing muffs or in water) and immediately check for a steady stream from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific Mercury outboard?
A: This kit is designed for Mercury 3.4L V6 and 4.6L V8 4-stroke outboards from 2019 and newer, specifically with a serial number of 2B529482 and above. Please check your engine's serial number plate to confirm compatibility before ordering.

Q: What are the signs my water pump is failing and needs replacement?
A: Common signs of a failing water pump include a weak or no water stream from the "tell-tale" outlet, engine overheating alarms, or steam from the exhaust. Reduced engine performance at high RPMs can also indicate a cooling issue.

Q: How often should I replace my outboard's water pump kit?
A: As a crucial part of preventative maintenance, it is recommended to inspect the impeller annually and replace the entire water pump kit every two to three years or every 200-300 hours of use. This interval may be shorter if you frequently operate in sandy, silty, or saltwater conditions.

Q: Does this kit include the plastic water pump housing?
A: No, this is a repair kit containing the primary wear components like the impeller, gaskets, seals, and face plate. The upper housing is not included and should be inspected for warping or damage before installing this kit.

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.