Water Pump Impeller Repair Kit – Fits Mercury Marine 13.5-25 HP Outboards (Replaces Mercury 47-85089T7, 47-85089Q4)
Water Pump Impeller Repair Kit – Fits Mercury Marine 13.5-25 HP Outboards (Replaces Mercury 47-85089T7, 47-85089Q4) is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller Repair Kit – Fits Mercury Marine 13.5-25 HP Out...
Water Pump Impeller Repair Kit – Fits Mercury Marine 13.5-25 HP Outboards (Replaces Mercury 47-85089T7, 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 a range of Mercury Marine and Force outboard engines. It provides a reliable solution for servicing the lower unit cooling system on Mercury 4-stroke and 2-stroke 13.5 HP, 15 HP, 18 HP, and 25 HP models from 1984–2005, as well as Force 25 HP engines manufactured between 1996–1998 (serial numbers E127700-E344999).
It serves as a direct replacement for Mercury part numbers 47-85089T7 and 47-85089Q4, and interchanges with Sierra 18-3215 and GLM 12107.
- Installation Location: Mounts in the lower unit gearcase to restore water circulation.
- Durable Materials: Features a marine-grade CR-Neoprene water pump impeller and a stainless steel (SS316) wear plate for corrosion resistance and longevity.
- Aftermarket Kit: This kit is designed to meet or exceed OEM specifications for reliable performance in marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury | 47-85089T7 |
| Mercury | 47-85089Q4 |
| Sierra | 18-3215 |
| GLM | 12107 |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure accurate fitment.
For Mercury Marine Owners: This kit fits specific 4-stroke and 2-stroke models from 13.5 HP to 25 HP manufactured between 1984 and 2005. Pay close attention to serial numbers where noted.
For Force Owners: Compatibility is confirmed for 25 HP models within the serial number range E127700 to E344999 (1996–1998).
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | Various | 13.5 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | Various | 15 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | Various | 18 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | Various | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | 25 XD | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | 25 SeaPro | 25 | 4-Stroke | 1984–2005 | 47-85089T7 | |
| Mercury | 3 Cylinder | 25 | 4-Stroke | Up to 2005 | 47-85089T7 | Serial #E268781-UP |
| Force | Various | 25 | 1996–1998 | 47-85089T7 | Serial #E127700-E344999 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Lower Unit Gearcase
- Impeller Material
- Marine Grade CR-Neoprene
- Wear Plate Material
- Marine Grade SS316
- Other Technical Attributes
- Aftermarket replacement kit designed for Mercury Marine outboard lower units
What’s in the Box
- 1 x Impeller (47-85089-3/47-85089-10)
- 1 x Wear Plate (85083)
- 2 x Gaskets (27-993261)
Installation Notes
- Disconnect the battery and shift the outboard into neutral.
- Remove the lower unit (gearcase) by unbolting it from the engine's midsection. Be prepared for it to be heavy.
- Place the lower unit on a workbench. Locate and remove the bolts securing the water pump housing.
- Carefully lift the housing off, noting the position of the old impeller, key, gaskets, and wear plate.
- Clean all mating surfaces thoroughly, removing any old gasket material or sealant residue.
- Install the new wear plate and gaskets. Lightly lubricate the inside of the housing and the new impeller with marine grease.
- Insert the impeller key into the driveshaft and slide the new impeller down over it, turning the shaft clockwise to seat the vanes correctly inside the housing.
- Reinstall the water pump housing and torque the bolts to the manufacturer's specified value.
- Re-attach the lower unit to the midsection, ensuring the driveshaft and shift shaft align properly.
- Once assembled, test the engine using a water supply (flushing attachment or test tank) to confirm water is pumping correctly from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my engine?
This kit is for specific Mercury and Force outboards. For Mercury, it generally fits 13.5 HP to 25 HP models from 1984–2005. For Force, it fits 25 HP models from 1996–1998 with serial numbers E127700 to E344999. Always cross-reference your engine's OEM part number with the ones provided in our Part Number Matrix and check the detailed compatibility table.
What are the signs of a failing water pump impeller?
Common signs include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and a noticeable decrease in engine performance. A damaged impeller can also produce a faint rattling or grinding noise from the lower unit.
How often should I replace my water pump impeller?
As a general maintenance rule, it's recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use, whichever comes first. This interval can be shorter if you frequently operate in sandy, silty, or saltwater conditions.
My 20 HP Mercury isn't listed, is it compatible?
Some sources suggest compatibility with 20 HP models, but our data is inconclusive. We have omitted it from the official list to prevent incorrect orders. Do not purchase this kit for a 20 HP model unless you can confirm your existing part is an exact match to OEM number 47-85089T7 or 47-85089Q4.
What's the difference between this and an OEM part?
This listing is for an aftermarket replacement part, not an original equipment manufacturer (OEM) component. It has been engineered to meet or exceed OEM-level specifications using comparable high-quality materials. Our products are manufactured in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.
How fast is shipping and what does it cost?
We ship worldwide quickly, with a typical transit time of 5–15 days for most regions. Standard shipping is free. If available for your location, expedited shipping options and their costs will be presented at checkout.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal marine use. Should an issue arise, please contact our support team with your order details for assistance. Returns are accepted within our standard window for items that are unused and in their original condition. You can see our full policy page or reach out for specific instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears on the compatibility list—do not purchase.
- This is an aftermarket replacement component, not an OEM part.
- Professional installation is highly recommended for safety and optimal 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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
