Water Pump Impeller for Mercury/Mariner 2-Stroke 3.5–6 HP – Replaces 47-22748
Water Pump Impeller for Mercury/Mariner 2-Stroke 3.5–6 HP – Replaces 47-22748 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller for Mercury/Mariner 2-Stroke 3.5–6 HP – Replace...
Water Pump Impeller for Mercury/Mariner 2-Stroke 3.5–6 HP – Replaces 47-22748 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller is designed for selected Mercury and Mariner 2-stroke outboards rated 3.5, 3.9, 5, and 6 HP. It replaces Mercury OEM part number 47-22748 and aftermarket reference Sierra 18-3012. Replace a worn or damaged impeller to help restore proper water-pump circulation and cooling-system performance.
This listing is for one replacement impeller only. It is not an OEM Mercury component and does not include a water-pump housing, gasket, wear plate, drive key, or other installation hardware unless separately specified.
- Replacement water pump impeller for selected Mercury and Mariner 2-stroke outboards.
- Company-specified fitment: 3.5 HP, 3.9 HP, 5 HP, and 6 HP models.
- Replaces Mercury OEM reference 47-22748.
- Single impeller supplied; verify the original part and engine identification before ordering.
Part Number Matrix
These are customer-facing manufacturer and aftermarket reference numbers associated with this impeller. Cross-reference numbers are provided for identification; always confirm the complete engine model and serial number before installation.
| Brand | Part Number | Reference Type |
|---|---|---|
| Mercury | 47-22748 | OEM replacement reference |
| Sierra | 18-3012 | Aftermarket reference |
Engine & Model Compatibility
The company catalog specifies compatibility with Mercury and Mariner 2-stroke outboards in the 3.5, 3.9, 5, and 6 HP ranges. Horsepower alone is not sufficient to confirm fitment, so compare the complete model and serial number with your engine parts diagram before ordering.
| Brand | Rated HP | Stroke | OEM Part No. | Fitment Notes |
|---|---|---|---|---|
| Mercury / Mariner | 3.5 | 2-Stroke | 47-22748 | Confirm the exact model and serial number. |
| Mercury / Mariner | 3.9 | 2-Stroke | 47-22748 | Confirm the exact model and serial number. |
| Mercury / Mariner | 5 | 2-Stroke | 47-22748 | Confirm the exact model and serial number. |
| Mercury / Mariner | 6 | 2-Stroke | 47-22748 | Catalog records include a Mercury 6 HP model 60 application with serial range 1408611 through 1916138. |
Important: Do not assume compatibility with 9.8 HP, 9.9 HP, or other models solely because they use a similar-looking impeller. Confirm the application against the engine's model and serial number.
Technical Specs
- Product Type
- Water pump impeller
- Application
- Selected Mercury and Mariner 2-stroke outboards
- Rated HP Range
- 3.5, 3.9, 5, and 6 HP
- OEM Replacement Reference
- Mercury 47-22748
- Aftermarket Reference
- Sierra 18-3012
- Product Configuration
- Single replacement impeller
- Installation
- Install according to the applicable engine service manual and water-pump assembly requirements.
What’s in the Box
- 1 × Water pump impeller
Water-pump housing components, gaskets, wear plates, keys, pins, and other hardware are not included unless separately listed.
Installation Notes
- Disconnect the battery, remove the emergency-stop lanyard, and follow the safety procedures in the applicable service manual.
- Place the outboard in neutral and remove the lower unit according to the manufacturer's procedure.
- Locate the water-pump housing and remove the cover and related components as specified by the service manual.
- Remove the old impeller and inspect the housing, wear plate, drive shaft, pin or key arrangement, and associated seals for wear or damage.
- Clean debris and corrosion from the water-pump area before installing the replacement.
- Install the impeller in the correct orientation for your engine's water-pump design. Do not force the impeller or omit any required pin, key, gasket, or seal.
- Reassemble the water pump and lower unit using the manufacturer's torque specifications.
- Test the cooling-water flow with an appropriate flush attachment before operating the outboard on the water.
Installation should be performed by a qualified technician when the correct water-pump configuration or engine serial range is uncertain.
Troubleshooting & FAQ
How do I confirm this impeller fits my engine?
Confirm that your engine is a Mercury or Mariner 2-stroke model rated 3.5, 3.9, 5, or 6 HP, then verify the complete model and serial number against the engine parts diagram. Also compare the old impeller's dimensions, hub, and drive-pin or key arrangement before ordering.
Does this impeller fit a 9.8 or 9.9 HP outboard?
The company fitment for this product is limited to 3.5, 3.9, 5, and 6 HP 2-stroke applications. Do not use this listing for a 9.8 or 9.9 HP engine unless the exact engine parts catalog confirms the same replacement reference and application.
What are the signs of a failing water-pump impeller?
Common signs include weak or absent cooling-water flow, overheating, an overheat warning, or visible cracking, brittleness, deformation, or missing vanes when the impeller is inspected.
How often should I replace the impeller?
Replacement intervals depend on the engine manufacturer's maintenance schedule and operating conditions. Inspect the impeller during scheduled service and replace it when it is worn, damaged, hardened, or when cooling-water flow is inadequate.
Is this an OEM Mercury part?
No. This is an aftermarket replacement impeller identified for use in applications that reference Mercury OEM part number 47-22748 and Sierra reference 18-3012.
Does the package include a key, gasket, or water-pump kit?
No. This listing is for one impeller only. Confirm and purchase any required key, pin, gasket, seal, housing, or other water-pump components separately if they are not already serviceable on your engine.
Safety & Important Info
- Verify the engine brand, model, horsepower, stroke, and serial number before purchase.
- Compare the old impeller and the water-pump assembly, including the hub and drive-pin or key arrangement.
- This is an aftermarket replacement, not an OEM Mercury component.
- Never operate an outboard without adequate cooling-water flow. Stop the engine immediately if overheating or a loss of telltale flow occurs.
- Professional installation is recommended when the application or installation procedure is uncertain.
About Sea Sierra
- Marine Replacement Parts — Replacement components for selected outboard and marine applications.
- Application-Focused Listings — Product references and fitment information are provided to help customers compare parts before ordering.
- Customer Support — Contact support with your engine model and serial number if you need help checking an application.
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