Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 15-25HP & 4-Stroke 9.9-15HP (Replaces 99157T2, 46-99157T2)
Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 15-25HP & 4-Stroke 9.9-15HP (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/Mariner 2-Stroke 15-25HP &...
Product Details
This Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 15-25HP & 4-Stroke 9.9-15HP (Replaces 99157T2, 46-99157T2) is a complete assembly designed to restore your outboard's cooling system performance. It is engineered for a wide range of Mercury/Mariner 2-stroke (15-25 HP) and 4-stroke (9.9-15 HP Bigfoot) models from 1980–1998, as well as select Force 25 HP engines from 1995–1998.
This kit serves as a direct replacement for multiple part numbers, including Mercury 99157T2, 99157A2, 85098A2, Sierra 18-3215, and GLM 12014, ensuring broad interchange compatibility.
- Installs as a direct-fit replacement for the original pump.
- Features a durable Stainless Steel 316 housing for superior corrosion resistance.
- Includes all necessary gaskets, seals, and hardware for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 99157T2 |
| Mercury | 99157A2 |
| Mercury | 85098A2 |
| Sierra | 18-3215 |
| GLM | 12014 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit fits specific serial number ranges for Mercury, Mariner, and Force outboards. Always verify your engine's serial number to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2/99157A2/85098A2 | USA Serial #5837437 & Up |
| Mercury | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2/99157A2/85098A2 | USA Serial #6443973-0T800749 |
| Mercury | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 99157T2/99157A2/85098A2 | USA Serial #5705532 & Up |
| Mercury | 25 (3-Cyl.) | 25 | 2-Stroke | 1997 & Up | 99157T2/99157A2/85098A2 | USA Serial #0E268781 & Up |
| Mercury | 25 Sea Pro/Marathon/Super 15 | 25 | 2-Stroke | 1988–1998 | 99157T2/99157A2/85098A2 | USA Serial #0B238464 & Up |
| Mercury | 9.9 Bigfoot (323cc) | 9.9 | 4-Stroke | 1998 | 99157T2/99157A2/85098A2 | USA Serial #0G760300-0T979999 |
| Mercury | 15 Bigfoot (323cc) | 15 | 4-Stroke | 1998 | 99157T2/99157A2/85098A2 | USA Serial #0G590000 & Up |
| Mariner | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2/99157A2/85098A2 | AUS Serial #8071973 & Up |
| Mariner | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2/99157A2/85098A2 | CAN Serial #7209533 & Up |
| Mariner | 25, 25XD | 25 | 2-Stroke | 1980–1983 | 99157T2/99157A2/85098A2 | AUS Serial #8073158 & Up |
| Mariner | 15 XD Bigfoot | 15 | 2-Stroke | 1997–1998 | 99157T2/99157A2/85098A2 | BEL Serial #9927000 & Up |
| Mariner | 9.9 Bigfoot (323cc) | 9.9 | 4-Stroke | 1998 | 99157T2/99157A2/85098A2 | BEL Serial #0P075166-0P325499 |
| Mariner | 15 Bigfoot (323cc) | 15 | 4-Stroke | 1998 | 99157T2/99157A2/85098A2 | BEL Serial #9973100 & Up |
| Force | 25 | 25 | 2-Stroke | 1996–1998 | 99157T2/99157A2/85098A2 | Serial #0E127700-0E344999 |
Technical Specs
- Product Type
- Water Pump Repair Kit with Housing
- Installation
- Direct Replacement
- Housing Material
- Stainless Steel 316
- Housing Color
- Metallic
- Dimensions
- Package: 151 × 103 × 52 mm (5.94 × 4.06 × 2.05 inches)
- Weight
- 0.29 kg (10.2 ounces)
- Warranty
- 1 Year Limited Warranty
What’s in the Box
- 1 x Housing, Pump Assembly (99157A02, 99157A1)
- 1 x Face Plate (85083)
- 1 x Gasket (993261)
- 1 x Key (8M0032838)
- 1 x Seal (85090001, 85090)
- 2 x Washer transparent (12-86645-1)
- 4 x Insulator (23-85095)
- 3 x O-ring
Installation Notes
- Disconnect the spark plug wires and secure the propeller.
- Place a drain pan under the gearcase and remove the drain screw to empty the gear oil.
- Remove the bolts connecting the lower unit (gearcase) to the upper driveshaft housing.
- Carefully lower the gearcase to expose the water pump assembly. You may need to disconnect a speedometer tube.
- Unbolt and remove the old water pump housing and impeller. Note the orientation of the old parts.
- Thoroughly clean the mounting surfaces, removing any old gasket material or debris.
- Install the new gasket, face plate, impeller (with key), and housing from the kit. Lubricate the new impeller with a small amount of soap or grease.
- Reassemble the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Tighten all bolts to the manufacturer's specified torque. Refill the gearcase with fresh oil.
- Reconnect spark plug wires and test the engine in a suitable water supply, confirming a steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine?
The most reliable way is to match your engine's serial number to the ranges listed in the compatibility table. While model, HP, and year are helpful, the serial number is the definitive identifier for ensuring correct part fitment.
What are the signs of a failing water pump?
Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet, or an audible alarm if your engine is equipped with one. Visible damage to the old impeller, such as cracked or missing vanes, also indicates failure.
How often should I replace my water pump impeller?
As a general maintenance guideline, impellers should be inspected annually and replaced every 1-2 years (or every 100-200 hours of use), regardless of visible wear. Proactive replacement prevents unexpected overheating and potential engine damage.
What is the difference between this aftermarket kit and an OEM one?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials like a Stainless Steel 316 housing for durability. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
What if my engine overheats after installing the new kit?
First, ensure the impeller was installed with the vanes pointing in the correct rotational direction and that the woodruff key is properly seated. Check for blockages in the cooling water intake ports and the outlet tube. Ensure all gaskets and seals are correctly seated to prevent air leaks.
Is everything needed for the job included in this kit?
This kit includes the water pump housing, impeller, face plate, key, gaskets, seals, and related hardware for a standard pump replacement. You will need your own tools and fresh gearcase oil.
How is shipping handled?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most regions, with expedited options available at checkout where applicable.
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 parts in their original packaging. 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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