Water Pump Impeller Repair Kit for Mercury and Force 13.5–25 HP Outboards – Replaces Mercury 47-85089T7 and 47-85089Q4
Water Pump Impeller Repair Kit for Mercury and Force 13.5–25 HP Outboards – Replaces Mercury 47-85089T7 and 47-85089Q4 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Impeller Repair Kit for Mercury and Force 13.5–25 HP Out...
Water Pump Impeller Repair Kit for Mercury and Force 13.5–25 HP Outboards – Replaces Mercury 47-85089T7 and 47-85089Q4 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller repair kit is designed for selected Mercury Marine and Force outboard engines. It provides replacement components for servicing the lower-unit cooling system on specified Mercury 4-stroke and 2-stroke 13.5 HP, 15 HP, 18 HP, and 25 HP models from 1984–2005, as well as selected Force 25 HP engines manufactured between 1996 and 1998. Always confirm the exact engine model, year, serial number, and original component before ordering.
The kit is listed as a replacement for Mercury part numbers 47-85089T7 and 47-85089Q4, with aftermarket reference numbers Sierra 18-3215 and GLM 12107.
- Installation Location: Water pump assembly in the lower-unit gearcase.
- Impeller Material: Marine-grade CR-neoprene for water-pump service.
- Wear Plate Material: Stainless steel SS316 for corrosion resistance.
- Replacement Kit: Includes an impeller, wear plate, and gaskets for the listed applications.
Part Number Matrix
Use the following references together with your original part and engine identification to check compatibility.
| Brand | Part Number |
|---|---|
| Mercury | 47-85089T7 |
| Mercury | 47-85089Q4 |
| Sierra | 18-3215 |
| GLM | 12107 |
Engine & Model Compatibility
Compatibility depends on the complete engine configuration. Confirm the brand, model, horsepower, stroke, production year, and serial-number range before purchase.
Mercury Marine: Listed applications include selected 4-stroke and 2-stroke 13.5 HP, 15 HP, 18 HP, and 25 HP outboards manufactured from 1984–2005. Some applications require a specific serial-number range.
Force: Listed compatibility includes selected 25 HP models manufactured from 1996–1998 with serial numbers E127700–E344999.
| Brand | Model | Rated HP | Stroke | Years | Reference Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | Various | 13.5 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | Various | 15 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | Various | 18 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | Various | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | 25 XD | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | 25 SeaPro | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | Verify exact model and serial number. |
| Mercury | 3 Cylinder | 25 | 4-Stroke | Up to 2005 | 47-85089T7 | Serial number E268781 and later. |
| Force | Various | 25 | Not specified | 1996–1998 | 47-85089T7 | Serial numbers E127700–E344999. |
Technical Specifications
- Product Type
- Water pump impeller repair kit
- Installation
- Lower-unit gearcase water pump assembly
- Impeller Material
- Marine-grade CR-neoprene
- Wear Plate Material
- Marine-grade SS316 stainless steel
- Application
- Aftermarket replacement kit for selected Mercury Marine and Force outboard applications
What’s in the Box
- 1 × Impeller, references 47-85089-3 / 47-85089-10
- 1 × Wear plate, reference 85083
- 2 × Gaskets, reference 27-993261
Installation Notes
- Disconnect the battery and place the outboard in neutral.
- Remove the lower unit from the engine midsection according to the manufacturer's service procedure.
- Place the lower unit on a stable workbench and remove the water-pump housing fasteners.
- Lift off the housing and note the orientation of the old impeller, key, gaskets, and wear plate.
- Clean all mating surfaces and remove old gasket material and sealant residue.
- Install the new wear plate and gaskets. Lightly lubricate the housing and impeller with a suitable marine lubricant.
- Install the impeller key on the driveshaft and slide the impeller into position while turning the shaft clockwise so the vanes seat correctly.
- Reinstall the water-pump housing and tighten the fasteners to the manufacturer's specified torque.
- Reattach the lower unit, ensuring the driveshaft and shift shaft align correctly.
- Test the engine with an appropriate flushing attachment or test tank and confirm a steady tell-tale water stream.
Follow the engine manufacturer's service manual for model-specific removal, installation, torque, and safety procedures. Professional installation is recommended when the correct procedure is not familiar.
Troubleshooting & FAQ
How do I know if this kit fits my engine?
This kit is intended for selected Mercury and Force outboards. Compare your existing component with the listed Mercury, Sierra, and GLM references, then verify the complete engine model, year, horsepower, stroke, and serial-number requirements. For Force 25 HP applications, verify serial numbers E127700–E344999. Do not rely on horsepower alone.
What are the signs of a failing water-pump impeller?
Common signs include a weak or absent tell-tale water stream, an overheating warning, or rising engine temperature. A damaged impeller may also cause abnormal noise from the lower unit. Stop operating the engine if it overheats and inspect the cooling system.
How often should I replace a water-pump impeller?
Inspect the impeller as part of regular maintenance and replace it according to the engine manufacturer's service schedule. Frequent operation in sandy, silty, or saltwater conditions may require more frequent inspection and replacement.
My 20 HP Mercury is not listed. Is it compatible?
20 HP compatibility is not confirmed by the listed application information. Do not purchase this kit for a 20 HP model unless the original component and application data confirm an exact match to 47-85089T7 or 47-85089Q4.
What is the difference between this and an OEM part?
This listing is for an aftermarket replacement kit, not an original-equipment Mercury component. It is intended to provide comparable service for the listed applications. Confirm dimensions, component shape, and part-number references before installation.
How fast is shipping and what does it cost?
Standard shipping is free where offered. Typical transit time is 5–15 days for many regions. Available expedited shipping methods and costs are shown at checkout based on destination and service availability.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal marine use. Returns are accepted within the applicable return period for unused items in their original condition. Contact support with your order details for warranty or return instructions.
Safety & Important Information
- Verify the original part number, dimensions, engine model, year, horsepower, stroke, and serial number before ordering.
- Do not operate an outboard without an adequate water supply for cooling.
- This is an aftermarket replacement kit, not an OEM Mercury component.
- Professional installation is recommended for safe and reliable operation.
About Sea Sierra
- Pro-Grade Standards — Marine replacement parts designed for demanding real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions where available, with typical transit times of 5–15 days.
- Manufacturer-Direct Value — Practical replacement solutions with attention to materials and quality control.
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