Water Pump Repair Kit – Fits Mercury Marine 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP (Replaces 99157T2, 46-99157T2)
Water Pump Repair Kit – Fits Mercury Marine 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP (Replaces 99157T2, 46-99157T2) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Repair Kit – Fits Mercury Marine 2-Stroke 15-25 HP &...
Product Details
This Water Pump Repair Kit is an aftermarket replacement designed for a wide range of Mercury and Mariner outboards, including 2-stroke 15-25 HP models (1980–2005) and 4-stroke 9.9-15 HP BigFoot models (1998–2005). It also provides coverage for select Force 25 HP (1994-1998) and Sears Gamefisher 25 HP (1994-1998) engines, ensuring broad compatibility for lower unit maintenance.
This kit serves as a direct cross-reference for Mercury part numbers 99157T2, 46-99157T2, 85098A2, 99157A2, 46-85098A2; Quicksilver 85089Q4; and Sierra 18-3549.
- Engineered for a direct OEM-replacement fit for straightforward installation.
- Constructed with a durable neoprene impeller and stainless steel housing components for saltwater and freshwater use.
- Includes all necessary seals, gaskets, and hardware for a complete upper water pump service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Mercury | 99157T2 / 46-99157T2 |
| Mercury | 85098A2 / 99157A2 / 46-85098A2 |
| Quicksilver | 85089Q4 |
| Sierra | 18-3549 |
Engine & Model Compatibility
Confirm your engine model/year in the table below. Verifying serial numbers is crucial for precise fitment.
For Mercury and Mariner models, check that your engine's serial number falls within the specified range to ensure a correct match.
For Force and Sears models, compatibility is determined by the model year and horsepower rating.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | BigFoot | 9.9 (323cc) | 4-Stroke | 1998–2005 | 99157T2 | USA ser# 0G760300-0T979999, BEL ser# 0P075166-0P325499 |
| Mercury | BigFoot | 15 (323cc) | 4-Stroke | 1998 | 99157T2 | USA ser# 0G590000 & Up, BEL ser# 9973100 & Up |
| Mercury | XD, BigFoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | BEL ser# 9927000 & Up |
| Mercury | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2 | USA ser# 5837437 & Up, AUS ser# 8071973 & Up, BEL ser# 9308306 & Up |
| Mercury | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2 | USA ser# 6443973-0T800749, BEL ser# 9415101 & Up, CAN ser# 7209533 & Up |
| Mercury | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 99157T2 | USA ser# 5705532 & Up, AUS ser# 8073158 & Up |
| Mercury | 25 (3-Cyl) | 25 | 2-Stroke | 1997 & Up | 99157T2 | USA ser# 0E268781 & Up |
| Mercury | 25 Sea Pro, Marathon, Super 15 | 25 | 2-Stroke | 1988–1998 | 99157T2 | USA ser# 0B238464 & Up, BEL ser# 9507381 & Up, CAN ser# 0A730007 & Up |
| Mariner | BigFoot | 9.9 (323cc) | 4-Stroke | 1998–2005 | 99157T2 | Similar to Mercury applications |
| Mariner | BigFoot | 15 (323cc) | 4-Stroke | 1998 | 99157T2 | Similar to Mercury applications |
| Mariner | 15 XD, BigFoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | Similar to Mercury applications |
| Mariner | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2 | Similar to Mercury applications |
| Mariner | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2 | Similar to Mercury applications |
| Mariner | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 99157T2 | Similar to Mercury applications |
| Mariner | 25 (3-Cyl) | 25 | 2-Stroke | 1997 & Up | 99157T2 | Similar to Mercury applications |
| Mariner | 25 Sea Pro, Marathon, Super 15 | 25 | 2-Stroke | 1988–1998 | 99157T2 | Similar to Mercury applications |
| Force | 25 | 25 | 2-Stroke | 1994–1998 | 99157T2 | Multiple model codes including H025201RD [MH], H025211RD [MLH] |
| Sears | Gamefisher 25 | 25 | 2-Stroke | 1994–1998 | 99157T2 | Models include 225.582500, 225.592500 |
Technical Specs
- Product Type
- Upper Water Pump Repair Kit
- Installation
- Direct OEM replacement
- Fuel Type
- Gasoline
- Housing Material
- Stainless Steel 316, Plastic
- Impeller Material
- Neoprene Rubber
- Package Dimensions
- 151 × 108 × 52 mm (5.94 × 4.06 × 2.05 inches)
- Package Weight
- 0.289 kg (10.2 ounces)
- Additional Components
- Includes key plate, cup bolts, housing, impeller seals
What’s in the Box
- 1 x Water Pump Impeller (47-85089-3, 47-85089-10, 8508910)
- 1 x Housing, Pump Assembly (99157A02, 99157A1)
- 1 x Face Plate (85083)
- 1 x Gasket (993261)
- 1 x Key (8M0032838)
- 1 x Seal (85090, 85090001)
- 2 x Washer (12-86645-1)
- 4 x Insulator/Grommet (23-85095)
- 3 x O-ring
Installation Notes
- Disconnect the negative battery cable and remove the engine cowling.
- Place a drain pan under the lower unit and remove the gearcase oil drain/fill screw to empty the oil.
- Remove the bolts securing the lower unit (gearcase) to the driveshaft housing.
- Carefully lower and separate the gearcase from the upper housing, minding the shift shaft.
- Unbolt and remove the old water pump housing, impeller, face plate, and gaskets.
- Thoroughly clean the driveshaft and all mating surfaces of any old gasket residue or corrosion.
- Slide the new key and impeller onto the driveshaft. Install the new gaskets, face plate, and pump housing.
- Lightly grease the inside of the pump cup and the new O-rings before assembly.
- Tighten the pump housing bolts to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Refill the gearcase with the correct type and amount of marine gear lubricant.
- Once fully assembled, start the engine in water and verify a strong, consistent stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump is failing?
The most common signs of a failing water pump are a weak or non-existent water stream from the engine's tell-tale outlet, frequent engine overheating alarms, and visible damage (cracks, brittleness) to the impeller upon inspection.
How often should I replace my engine's water pump impeller?
For preventative maintenance, it is recommended to replace the water pump impeller every 100-200 hours of use or once every one to two years, whichever comes first, especially if you operate in saltwater or debris-heavy water.
Will this kit fit my engine if the serial number isn't listed?
The serial number ranges provided are critical for ensuring proper fitment. If your engine's serial number is outside the specified range, this kit is likely not compatible. Always verify by cross-referencing your engine's original part number.
What is the difference between this kit and the OEM version?
This is an aftermarket replacement kit, not an original equipment manufacturer (OEM) part. It has been designed and manufactured to meet or exceed OEM specifications for fit, form, and function, using comparable high-quality materials.
Do I need special tools for installation?
Basic hand tools such as a socket/ratchet set, wrenches, and a screwdriver are typically sufficient. A torque wrench is highly recommended to ensure all bolts are tightened to the proper manufacturer specifications to prevent leaks and damage.
Is grease required for installation?
Yes, applying a light coat of marine-grade grease to the impeller, O-rings, and inside the pump housing will aid in assembly and improve the initial priming of the pump upon first start-up.
How fast do you ship?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
Our parts are covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not order.
- This product is an aftermarket replacement part, not an OEM component. Brand names and part numbers are used for reference purposes only.
- Professional installation is highly recommended to ensure safety and proper performance. Incorrect installation can lead to engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with an average transit time of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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