Water Pump Kit – Fits Mercury/Mariner 15-25 HP 2-Stroke & 9.9-15 HP 4-Stroke (Replaces 99157T2, 46-99157T2)
Water Pump Kit – Fits Mercury/Mariner 15-25 HP 2-Stroke & 9.9-15 HP 4-Stroke (Replaces 99157T2, 46-99157T2) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Kit – Fits Mercury/Mariner 15-25 HP 2-Stroke & 9.9-1...
Product Details
This Water Pump Kit – Fits Mercury/Mariner 15-25 HP 2-Stroke & 9.9-15 HP 4-Stroke (Replaces 99157T2, 46-99157T2) is a direct-fit upper housing repair assembly for a range of outboard engines. It is designed for Mercury/Mariner 2-Stroke models from 15–25 HP (1980–1998), 4-Stroke 9.9–15 HP Bigfoot models (1998 and newer), and Force 25 HP 2-Stroke outboards (1995–1998).
This kit serves as a direct interchange for Mercury part numbers 99157T2, 85098A2, 99157A2, 46-99157T2, 46-85098A2, and 46-99157A2.
- Engineered as a direct replacement for the original upper pump housing.
- Constructed with a durable plastic housing and stainless steel internal components.
- Includes all essential marine-grade hardware for a complete upper housing refresh.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 99157T2 |
| Mercury | 85098A2 |
| Mercury | 99157A2 |
| Mercury | 46-99157T2 |
| Mercury | 46-85098A2 |
| Mercury | 46-99157A2 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury and Mariner outboards, verify your engine's serial number falls within the specified range for an exact match.
For Force outboards, this kit fits specific 25 HP models from 1995–1998 based on the serial number.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 15 (E/EH/EL/ELH/MH/MLH) 4-Stroke | 15 | 4-Stroke | 1998+ | 99157T2 | 4-Stroke models |
| Mercury | 15 (XD) Bigfoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | Serial #9927000 & Up |
| Mercury | 18/18XD | 18 | 2-Stroke | 1980–1985 | 99157T2 | Serial #5837437 & Up |
| Mercury | 20/20XD | 20 | 2-Stroke | 1986–1987 | 99157T2 | Serial #6443973-0T800749 |
| Mercury | 25/25XD | 25 | 2-Stroke | 1980–1987 | 99157T2 | Serial #5705532 & Up |
| Mercury | 25 Sea Pro/Super 15 | 25/15 | 2-Stroke | 1988–1998 | 99157T2 | Serial #0B238464 & Up |
| Mercury | 25 (3-Cylinder) | 25 | 2-Stroke | 1997+ | 99157T2 | Serial #0E268781 & Up |
| Mercury | 9.9 Bigfoot (323cc) | 9.9 | 4-Stroke | 1998+ | 99157T2 | Serial #0G760300-0T979999 |
| Mariner | 15 (Various) | 15 | 2-Stroke | 1988–1994 | 99157T2 | Multiple models |
| Mariner | 20 (Various) | 20 | 2-Stroke | 1984–1998 | 99157T2 | Multiple models |
| Mariner | 25 (Various) | 25 | 2-Stroke | 1984–1998 | 99157T2 | Multiple models |
| Mariner | 9.9 Bigfoot/15 Bigfoot | 9.9/15 | 4-Stroke | 1998+ | 99157T2 | 323cc 4-Stroke models |
| Force | 25 | 25 | 2-Stroke | 1995–1996 | 99157T2 | Serial #0E127700 & Up |
| Force | 25 | 25 | 2-Stroke | 1997–1998 | 99157T2 | Serial #0E288000-0E344999 |
Technical Specs
- Product Type
- Water Pump Repair Kit (Upper Housing)
- Fitment
- Direct replacement
- Housing Material
- Plastic with stainless steel housing components
- Package Dimensions
- 11.0 × 11.0 × 11.0 in
- Product Weight
- 0.29 kg (10.2 oz)
- Hardware
- Marine-grade components with stainless steel hardware
What’s in the Box
- 1 x Water Pump Housing Assembly (99157T2)
Installation Notes
- Disconnect the battery and shift the outboard into neutral.
- Remove the lower unit (gearcase) by unbolting it from the engine's midsection.
- Locate and unbolt the existing water pump housing. Carefully lift it off the driveshaft.
- Clean the mounting surface and driveshaft spline area thoroughly, removing any old gasket material or debris.
- Slide the new water pump housing assembly down the driveshaft, ensuring the impeller key is aligned.
- Fasten the new housing with the provided hardware, tightening bolts to the manufacturer's recommended torque specification.
- Reinstall the lower unit, ensuring the driveshaft and shift shaft align correctly.
- Reconnect the battery and test the engine with a water supply to verify proper pump operation.
Troubleshooting & FAQ
How do I know if this kit is correct for my engine?
This kit is designed for specific Mercury, Mariner, and Force models. The most reliable way to confirm fitment is by checking your engine's serial number against the ranges listed in the compatibility table. Do not rely on HP or year alone.
What are the signs of a failing water pump?
Common symptoms include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, and in severe cases, steam from the exhaust. Reduced cooling performance can cause significant engine damage if ignored.
How often should the water pump assembly be replaced?
As a general maintenance guideline, the entire water pump assembly, including the impeller and housing, should be inspected annually and replaced every 2-3 years or 200-300 hours of use, whichever comes first. This interval can be shorter if you operate frequently in sandy or silty water.
Is this the complete water pump kit or just the upper housing?
This kit contains the upper water pump housing assembly as pictured. It is not a complete kit with an impeller, gaskets, and wear plates, which may need to be sourced separately depending on your repair needs.
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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