Water Pump Impeller with Key – Fits Mercury/Mariner 6–15 HP 2-Stroke and Select 4-Stroke Models (Replaces 47-42038Q02, Sierra 18-3062)
Water Pump Impeller with Key – Fits Mercury/Mariner 6–15 HP 2-Stroke and Select 4-Stroke Models (Replaces 47-42038Q02, Sierra 18-3062) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Pump Impeller with Key – Fits Mercury/Mariner 6–15 HP 2-Strok...
Water Pump Impeller with Key – Fits Mercury/Mariner 6–15 HP 2-Stroke and Select 4-Stroke Models (Replaces 47-42038Q02, Sierra 18-3062) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller with drive key is designed for selected Mercury and Mariner outboards. The product is supplied as a single impeller-and-key replacement, not as a complete water-pump gasket kit. Company fitment information covers 2-stroke engines from 6 to 15 HP and selected 4-stroke models including 8 HP, 9.9 HP with 323cc displacement, 13.5 HP international models, and 15 HP models.
The impeller is listed as an aftermarket replacement for Mercury references 47-42038, 47-42038-2, 47-42038Q02, 47-42038-1, and 47-420382. Sierra 18-3062 is a corresponding aftermarket reference.
- High-volume, long-vane water pump impeller design for the specified applications.
- Includes the matching drive key for installation with the impeller.
- Suitable for routine water-pump service when the engine model and serial number match the applicable application information.
- Aftermarket replacement; Mercury and Mariner are manufacturer trademarks used only to identify compatibility.
Part Number Matrix
Use these references to compare the replacement impeller with the part being removed. Part-number references do not replace model, stroke, and serial-number verification.
| Brand or Source | Part Number | Reference Type |
|---|---|---|
| Mercury | 47-42038 | OEM reference |
| Mercury | 47-42038-2 | OEM reference |
| Mercury | 47-42038Q02 | OEM reference |
| Mercury | 47-42038-1 | OEM reference |
| Mercury | 47-420382 | OEM reference |
| Sierra | 18-3062 | Aftermarket reference |
Engine & Model Compatibility
Fitment depends on the complete engine application. Before ordering, compare the engine brand, model, horsepower, stroke, displacement where applicable, and serial number with your service information and the original impeller.
| Brand | Application | Rated HP | Stroke | Additional Conditions |
|---|---|---|---|---|
| Mercury/Mariner | Selected outboard models | 6–15 | 2-Stroke | Verify the exact model and serial number before installation. |
| Mercury/Mariner | Selected 8 HP models | 8 | 4-Stroke | Includes the company-listed Bodensee/international application; verify the exact engine identification. |
| Mercury/Mariner | Selected 9.9 HP models | 9.9 | 4-Stroke | 323cc application listed by the company; verify model and serial number. |
| Mercury/Mariner | Selected international models | 13.5 | 4-Stroke | International application listed by the company; verify the exact engine identification. |
| Mercury/Mariner | Selected 15 HP models | 15 | 4-Stroke | Verify the exact model and serial number before ordering. |
Important: The 2-stroke and 4-stroke applications are not interchangeable solely because the horsepower is similar. Do not use this part unless the engine application and original impeller reference match.
Technical Specs
- Product Type
- Water pump impeller with drive key
- Vane Design
- High-volume, long-vane impeller
- Approximate Outside Diameter
- 2.3125 in (58.74 mm)
- Approximate Inside Diameter
- 0.500 in (12.70 mm)
- Installation
- Direct replacement for compatible applications; follow the engine service manual.
- Brand Status
- Aftermarket replacement, not an OEM component.
What’s in the Box
- 1 x Water pump impeller
- 1 x Matching impeller drive key
Gaskets are not included. Inspect the water-pump housing, plate, and existing gaskets during service and purchase any required replacement gaskets separately for your specific engine.
Installation Notes
Follow the engine manufacturer’s service manual for the correct procedure, torque values, sealing requirements, and model-specific precautions. General service steps are:
- Disconnect the battery and place the outboard in neutral.
- Remove the lower unit according to the service manual.
- Remove the water-pump housing and take out the old impeller and key.
- Clean the housing, plate, and shaft area. Remove debris and inspect the housing and wear surfaces for damage.
- Install the supplied drive key and impeller in the same orientation as the original part.
- Install the water-pump housing, guiding the impeller vanes in the correct direction of rotation. Replace damaged or unsuitable gaskets separately.
- Reinstall the lower unit and confirm that the driveshaft, shift shaft, and water tube are correctly aligned.
- Run the engine in water or with the correct flushing equipment and confirm a steady cooling-water discharge before normal operation.
Troubleshooting & FAQ
How do I confirm that this impeller fits my engine?
Compare your engine brand, model, horsepower, stroke, displacement where applicable, and serial number with the application information. Also compare the original impeller’s dimensions and part-number reference. Horsepower alone is not sufficient to confirm fitment.
What are the signs of a failing water-pump impeller?
Common signs include a weak or irregular tell-tale stream, overheating warnings, elevated operating temperature, or reduced cooling-water discharge. Vanes may become brittle, damaged, or permanently deformed with use.
Does this product include a gasket kit?
No. This product includes one water-pump impeller and one matching drive key. Gaskets are not included and must be sourced separately if required for your engine.
Is this an OEM Mercury or Mariner part?
No. This is an aftermarket replacement that references Mercury and Mariner applications and part numbers for compatibility identification.
How often should an impeller be replaced?
Replacement timing depends on the engine manufacturer’s maintenance schedule, operating hours, storage conditions, and water quality. Inspect the impeller regularly and replace it whenever the vanes show cracking, wear, deformation, or damage.
Can I use it on any 6–15 HP outboard?
No. The listed 6–15 HP range applies to selected Mercury and Mariner applications, primarily the company-listed 2-stroke range. Selected 4-stroke applications are also listed separately. Confirm the exact model and serial number before purchase.
Safety & Important Information
- Verify the application and original part before ordering; similar horsepower ratings do not guarantee interchangeability.
- Do not operate an outboard without an adequate cooling-water supply.
- Stop the engine immediately if the tell-tale stream is weak or the engine overheats.
- Use the service manual for installation procedure and torque specifications. Professional installation is recommended when servicing the lower unit or water pump.
- This is an aftermarket replacement, not an OEM component.
About Sea Sierra
- Marine replacement parts selected for practical service and routine maintenance applications.
- Clear compatibility information to help match the part to the correct engine application.
- Aftermarket value for watercraft owners and marine technicians.
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