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 (Replaces 8M0205803, 8M0142980) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
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Water Pump Repair Kit – Fits Mercury 175-300HP & 450R V6/V8 4-S...
Water Pump Repair Kit – Fits Mercury 175-300HP & 450R V6/V8 4-Stroke Outboards (Replaces 8M0205803, 8M0142980) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit is designed for Mercury Marine 175-300HP 3.4L V6 and 4.6L V8 4-stroke outboards, including 450R models, from 2019 and newer (serial number 2B529482 and above).
It serves as a direct replacement for Mercury part numbers 8M0205803, 8M0142980, 47-8M0205803, and 98-8M0142980.
- Engineered for direct-fit installation.
- Complete kit includes all necessary gaskets, seals, and a new impeller.
- Restores cooling system performance to prevent engine overheating.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 8M0205803 |
| Mercury | 8M0142980 |
| Mercury | 47-8M0205803 |
| Mercury | 98-8M0142980 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 3.4L V6 | 175 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 3.4L V6 | 200 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 3.4L V6 | 225 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 4.6L V8 | 200 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 4.6L V8 | 225 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 4.6L V8 | 250 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | 4.6L V8 | 300 | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
| Mercury | Racing | 450R | 4-Stroke | 2019 and newer | 8M0205803 | Serial no. 2B529482 and above |
Technical Specs
- Product Type
- Water Pump Repair Kit
- Installation
- Direct replacement
- Fitment Requirement
- For Mercury V6/V8 4-stroke outboards with serial number 2B529482 and above
What’s in the Box
- 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 Notes
- Disconnect the battery and remove the lower unit from the outboard motor.
- Remove the old water pump housing, impeller, gaskets, and seals.
- Clean all mating surfaces thoroughly, ensuring they are free of old gasket material and corrosion.
- Install the new gaskets, face plate, impeller (with key), and seals from the kit.
- Lubricate the inside of the housing and the impeller with marine grease before assembling.
- Reinstall the water pump housing and torque bolts to manufacturer specifications.
- Reattach the lower unit to the outboard and test the engine in the water to verify proper cooling function.
Troubleshooting & FAQ
How do I know if this kit fits my Mercury outboard?
This kit is for Mercury 3.4L V6 and 4.6L V8 four-stroke outboards (175–450HP) made in 2019 or later, specifically with a serial number of 2B529482 and above. Always check your serial number before ordering.
What are the signs of a failing water pump?
Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent "telltale" water stream, or an audible alarm from the engine's warning system.
How often should the water pump impeller be replaced?
As a preventative maintenance item, it's recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).
Is this kit difficult to install?
Installation requires basic mechanical skills and tools to drop the lower unit. If you are not comfortable with this process, we highly recommend professional installation to ensure proper function and avoid engine damage.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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