Water Pump Impeller Replacement for Mercury 175–300 HP and 450R V6/V8 4-Stroke Outboards
Water Pump Impeller Replacement for Mercury 175–300 HP and 450R V6/V8 4-Stroke Outboards is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Replacement for Mercury 175–300 HP and 450R V6/...
Water Pump Impeller Replacement for Mercury 175–300 HP and 450R V6/V8 4-Stroke Outboards is backordered and will ship as soon as it is back in stock.
Product Details
This water pump impeller replacement is intended for selected Mercury Marine 4-stroke outboards, including V6 3.4L and V8 4.6L models rated from 175 to 300 HP, as well as selected 450R racing outboards. The impeller is a service replacement for the water pump and helps maintain the cooling-water flow required for normal engine operation.
The listed application range includes 2019 and newer engines with serial numbers beginning at 2B529482, but fitment can vary by exact model, shaft configuration, and serial-number range. Confirm the complete engine identification and the original impeller before ordering.
Reference numbers associated with this application include Mercury 47-8M0142980, 8M0205803, and 98-8M0142980. These numbers are provided for identification and cross-reference purposes; verify the number against your engine before installation.
- Replacement water-pump impeller for selected Mercury 4-stroke outboards.
- Neoprene impeller construction for marine cooling-system service.
- Designed as a direct replacement when the application and dimensions match the original component.
Part Number Matrix
Use these reference numbers to compare the replacement with the component removed from your outboard.
| Brand | Reference Part Number |
|---|---|
| Mercury | 47-8M0142980 |
| Mercury | 8M0205803 |
| Mercury | 98-8M0142980 |
Engine & Model Compatibility
The following applications represent the listed fitment range. Always confirm the engine model, year, serial number, and original impeller dimensions before purchase.
| Brand | Model Group | Rated HP | Stroke | Listed Year and Serial Range | Reference Part No. | Application Notes |
|---|---|---|---|---|---|---|
| Mercury | V6 Outboards | 175 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 3.4L V6 application group |
| Mercury | V6 Outboards | 200 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 3.4L V6 application group |
| Mercury | V6 Outboards | 225 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 3.4L V6 application group |
| Mercury | V6 Outboards | 250 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 3.4L V6 application group |
| Mercury | V8 Outboards | 250 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 4.6L V8 application group |
| Mercury | V8 Outboards | 300 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | 4.6L V8 application group |
| Mercury | 450R Racing | 450 | 4-Stroke | 2019 and newer; S/N 2B529482+ | 47-8M0142980 / 8M0205803 | Verify the exact racing-engine serial range before ordering |
Technical Specs
- Product Type
- Water pump impeller replacement
- Application
- Selected Mercury V6 and V8 4-stroke outboards
- Installation
- Replacement component for the water-pump assembly
- Impeller Material
- Neoprene rubber
- Included Components
- Impeller only; confirm the package contents and reuse or replacement requirements for gaskets, seals, keys, and other water-pump components before installation
What's in the Box
- 1 x Water pump impeller
This listing is for the replacement impeller. A drive key, gaskets, seals, wear plate, housing, installation tool, or other water-pump components are not confirmed as included unless specifically shown in the order or package details.
Installation Notes
- Disconnect the negative battery cable and follow the service manual's safety instructions.
- Remove the lower unit or gearcase according to the manufacturer's procedure.
- Remove the water-pump cover and inspect the housing, wear plate, key, seals, and gaskets for wear or damage.
- Remove the old impeller and note the vane direction before installation.
- Clean the mating surfaces and remove old gasket material, debris, and corrosion.
- Install the replacement impeller using the correct key and any required new gaskets or seals for your engine. Turn the driveshaft in the specified direction while seating the vanes in the housing.
- Reassemble the water-pump cover and lower unit, tightening fasteners to the manufacturer's service-manual specifications.
- Restore the battery connection, start the engine only in an appropriate test environment, and verify a steady tell-tale water stream and normal operating temperature.
Troubleshooting & FAQ
How do I confirm that this impeller fits my Mercury outboard?
Compare the engine brand, model, horsepower, stroke, year, serial number, original impeller dimensions, and reference number. The listed application covers selected Mercury V6 3.4L and V8 4.6L 4-stroke outboards from 175 to 300 HP and selected 450R models, but not every engine in those horsepower groups is necessarily identical.
What are the signs of a worn water-pump impeller?
Possible symptoms include overheating, a weak or missing tell-tale stream, reduced cooling-water flow, or damaged, cracked, brittle, or permanently deformed impeller vanes. Inspect the pump housing and related components whenever the impeller is replaced.
How often should the impeller be replaced?
Replacement intervals depend on the engine manufacturer's maintenance schedule and operating conditions. Inspect the impeller at the recommended service interval and replace it sooner if the engine is used in saltwater, sandy, silty, or debris-filled water.
Is this an OEM Mercury component?
This listing is for an aftermarket replacement impeller. It is not represented as a genuine Mercury-branded component. Confirm dimensions and application details before installation.
Does this listing include a complete repair kit?
No complete kit contents are confirmed for this listing. The product is described as a replacement water-pump impeller; verify whether additional gaskets, seals, a key, or other service parts are required for your particular engine.
Safety & Important Info
- Confirm the full engine model, year, serial number, stroke, and original component before ordering.
- Do not rely on horsepower alone to determine fitment.
- Inspect the water-pump housing, wear plate, key, gaskets, and seals during installation.
- Use the manufacturer's service manual for removal procedures, torque values, cooling-system checks, and maintenance intervals.
- This is an aftermarket replacement component, not a genuine OEM Mercury part.
- Professional installation is recommended when the required service procedure is unfamiliar.
About Sea Sierra
- Marine Replacement Parts — Replacement components for routine outboard service and repair.
- Application-Focused Listings — Product information is organized around engine model, horsepower, stroke, year, and serial-number conditions.
- Fitment Verification — Compare the original component and complete engine identification before ordering.
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