Water Pump Impeller Repair Kit – Fits Mercury Marine 6-15 HP Outboards (Replaces 46-42089A5, 46-42040A5)
Water Pump Impeller Repair Kit – Fits Mercury Marine 6-15 HP Outboards (Replaces 46-42089A5, 46-42040A5) is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Repair Kit – Fits Mercury Marine 6-15 HP Outboa...
Product Details
This Water Pump Impeller Repair Kit provides the essential components for servicing the lower unit water pump on Mercury and Mariner 6–15 HP outboard engines manufactured between 1986 and 2005. It is designed for both 2-stroke and 4-stroke models and also fits select 1998 Force and Sears 9.9–15 HP outboards.
It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 46-42089A5 and 46-42040A5, Sierra 18-3149, and GLM 12305.
- Designed for direct installation in the lower unit water pump housing.
- Includes all necessary gaskets, seals, and hardware for a complete impeller service.
- 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 | 46-42089A5 |
| Mercury | 46-42089A4 |
| Mercury | 46-42089A3 |
| Mercury | 46-42040A5 |
| Mercury | 46-42040A3 |
| Mercury | 46-42040A1 |
| Mercury | 46-42040T5 |
| Sierra | 18-3149 |
| Sierra | 18-3149-2 |
| GLM | 12305 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Compatibility for Mercury, Mariner, Force, and Sears models is detailed below. Please check your specific model, year, and serial number (SN) range to ensure a correct fit.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 2-Stroke | 6 | 2-Stroke | 1986–Up (SN 0A197112 and Up) | 46-42089A5 | |
| Mercury | 2-Stroke | 8 | 2-Stroke | 1986–Up (SN 0A197112 and Up) | 46-42089A5 | |
| Mercury | 2-Stroke | 9.9 | 2-Stroke | 1986–Up (SN 0A197112 and Up) | 46-42089A5 | |
| Mercury | 2-Stroke | 10 | 2-Stroke | 1986–Up | 46-42089A5 | Includes Magnum/Marathon/SeaPro/Viking models |
| Mercury | 2-Stroke | 15 | 2-Stroke | 1988–Up (SN 0B292414 and Up) | 46-42089A5 | Includes Marathon/SeaPro models |
| Mercury | 4-Stroke (232cc) | 8 | 4-Stroke | 1995–2004 (SN 0G760300-0T178499) | 46-42089A5 | Includes Bodensee (International) models |
| Mercury | 4-Stroke (Non-Bigfoot) | 9.9 | 4-Stroke | 1999–2004 (SN 0G760300-0T979999) | 46-42089A5 | |
| Mercury | 4-Stroke (323cc Non-Bigfoot) | 13.5 | 4-Stroke | 1998–2004 | 46-42089A5 | International models |
| Mercury | 4-Stroke (323cc Non-Bigfoot) | 15 | 4-Stroke | 1998–2004 (SN 0G590000-1B727495) | 46-42089A5 | |
| Force | Outboard | 9.9 | 2-Stroke | 1998 | 46-42089A5 | |
| Force | Outboard | 15 | 2-Stroke | 1998 | 46-42089A5 | |
| Sears | Outboard | 9.9 | 2-Stroke | 1998 | 46-42089A5 | |
| Sears | Outboard | 15 | 2-Stroke | 1998 | 46-42089A5 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct replacement for lower unit water pump
- Housing Material
- Plastic/Metal composite
- Housing Color
- Black
- Fitting Type
- Direct OEM replacement
- Other Technical Attributes
- Complete repair kit with all components needed for impeller replacement
What’s in the Box
- 1 x Water pump impeller (47-42038Q02/420382/47-42038-2)
- 1 x Impeller Key
- 1 x Housing assembly (42089A2)
- 1 x Face Plate (42200)
- 1 x Gasket (19202/192043)
- 1 x Water pump base assembly (42040T5)
- 2 x Oil seal (413651)
- 2 x Washers
- 1 x Quad ring (822236)
- 1 x Screw
Installation Notes
- Disconnect the battery and spark plug wires for safety.
- Place the outboard in neutral and remove the lower unit (gearcase) bolts.
- Carefully separate the lower unit from the upper engine housing.
- Locate and unbolt the water pump housing on top of the lower unit.
- Remove the old impeller, gaskets, wear plate, and seals. Clean all surfaces thoroughly.
- Install the new seals, gaskets, wear plate, and impeller key.
- Install the new impeller, turning the driveshaft clockwise to set the vanes correctly.
- Bolt the new housing assembly back into place, ensuring proper alignment.
- Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Securely tighten all bolts to the manufacturer's torque specifications.
- Reconnect the battery and spark plugs, and test the engine in water to verify proper cooling.
Troubleshooting & FAQ
How do I know if this impeller kit fits my specific engine?
This kit is designed for a wide range of Mercury, Mariner, Force, and Sears outboards. The best way to confirm fitment is to check your engine's model, year, and serial number (SN) against the compatibility table provided on this page. If your engine is listed, the kit is a direct replacement.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, and in severe cases, steam coming from the exhaust. It's crucial to address these signs immediately to prevent engine damage.
How often should the water pump impeller be replaced?
As a preventative maintenance item, it is recommended to replace the water pump impeller every 1–2 years or every 100–200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater). Always consult your engine's service manual for specific intervals.
Is this kit compatible with both 2-stroke and 4-stroke models?
Yes, this kit fits a variety of both 2-stroke and 4-stroke engines within the specified horsepower and year ranges. Please refer to the detailed "Engine & Model Compatibility" table to verify your exact model.
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.
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