Water Pump Repair Kit – Fits Mercury & Mariner 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP (Replaces 99157T2, 85098A2, 99157A2)
Water Pump Repair Kit – Fits Mercury & Mariner 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP (Replaces 99157T2, 85098A2, 99157A2) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
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Water Pump Repair Kit – Fits Mercury & Mariner 2-Stroke 15-25 H...
Water Pump Repair Kit – Fits Mercury & Mariner 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP (Replaces 99157T2, 85098A2, 99157A2) is backordered and will ship as soon as it is back in stock.
Product Details
This upper Water Pump Repair Kit – Fits Mercury & Mariner 2-Stroke 15-25 HP & 4-Stroke 9.9-15 HP provides all necessary components to restore your outboard's cooling system. It is designed for various Mercury and Mariner 2-stroke 15–25 HP models (1980–1998) and 4-stroke Bigfoot 9.9–15 HP models (1998).
It serves as a direct replacement for Mercury OEM part numbers 46-99157T2, 46-99157A2, and 46-85098A2, as well as aftermarket equivalents like Marinepro 99157T2, GHmarine 99157T2, and UanofCn 99157T2.
- Engineered for a direct OEM fit and easy installation.
- Features a durable Stainless Steel 316 housing and a high-performance neoprene impeller.
- Includes all required gaskets, seals, and O-rings for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By |
|---|---|---|
| Mercury | 46-85098A2 | 99157A2 |
| Mercury | 46-99157A2 | 99157T2 |
| Mercury | 46-99157T2 | |
| Marinepro | 99157T2 | |
| GHmarine | 99157T2 | |
| UanofCn | 99157T2 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury outboards, this kit fits a range of 2-stroke and 4-stroke Bigfoot models. Verify your serial number for precise compatibility, especially for models spanning multiple ranges.
For Mariner outboards, this kit covers various 2-stroke and 4-stroke Bigfoot models from the 1980s and 1990s. Check model codes where noted.
Select Force and Sears Gamefisher models from the late 1990s are also compatible. Ensure your model and serial number match the listed ranges.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 15 (E, EH, EL, ELH) 4 | 15 | 4-Stroke | 1998 | 99157T2 | Bigfoot models |
| Mercury | 15 (MH, MLH, MLH/ALT, MLH/BF) 4 | 15 | 4-Stroke | 1998 | 99157T2 | Bigfoot models |
| Mercury | 9.9 Bigfoot | 9.9 | 4-Stroke | 1998 | 99157T2 | USA ser# 0G760300-0T979999, BEL ser# 0P075166-0P325499 |
| Mercury | 15 XD Bigfoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | BEL ser# 9927000 & Up |
| Mercury | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 85098A2/99157A2/99157T2 | USA ser# 5837437 & Up, AUS ser# 8071973 & Up, BEL ser# 9308306 & Up |
| Mercury | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157A2/99157T2 | USA ser# 6443973-0T800749, BEL ser# 9415101 & Up, CAN ser# 7209533 & Up |
| Mercury | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 85098A2/99157A2/99157T2 | 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 | 15 (E, EH, EL, EL/BF, ELH, MH, MLH) 4 | 15 | 4-Stroke | 1998 | 99157T2 | Bigfoot models |
| Mariner | 15 MLA | 15 | 2-Stroke | 1994 | 99157T2 | Model code 70152374D |
| Mariner | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 85098A2/99157A2/99157T2 | |
| Mariner | 20 (E, EH, EL, M, MH, ML, MLH) | 20 | 2-Stroke | 1984–1998 | 85098A2/99157A2/99157T2 | Multiple model codes |
| Mariner | 25 (E, EH, EL, ELH, MH, ML, MLH) | 25 | 2-Stroke | 1980–1998 | 85098A2/99157A2/99157T2 | Multiple model codes |
| Mariner | 25 JET 20 | 25 | 2-Stroke | 1994–1998 | 99157T2 | |
| Mariner | 25 MH/ALT, MLH/ALT | 25 | 2-Stroke | 1994–1998 | 99157T2 | |
| Force | 25 | 25 | 2-Stroke | 1995–1998 | 99157T2 | Various serial ranges |
| Sears | Gamefisher | 25 | 2-Stroke | 1997–1998 | 99157T2 | Models 225.582500, 225.582501, 225.582591, 225.592500, 225.592590 |
Technical Specs
- Product Type
- Upper Water Pump Repair Kit
- Installation
- OEM Direct Fit Replacement
- Housing Material
- Stainless Steel 316
- Housing Color
- Silver/Metallic
- Dimensions
- Approx. 6.2 × 4.3 × 1.9 inches (157.5 × 109.2 × 48.3 mm)
- Weight
- 0.5 lb (0.23 kg)
- Fitting Type
- Direct OEM Fit
- Other Technical Attributes
- Neoprene impeller, rubber O-rings, stainless steel housing
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
- 1 x Impeller (47-85089/8M0024502/8508910)
- 1 x Water Tube Guide Sleeve
- 2 x Gear Lube Fill and Vent Screw O-rings
Installation Notes
- Disconnect the negative battery cable and remove the engine cowling. Shift the outboard into neutral.
- Remove the bolts securing the lower unit (gearcase) to the upper leg and carefully lower it.
- Unbolt and remove the old water pump housing. Note the orientation of the old impeller vanes.
- Thoroughly clean the driveshaft and mating surfaces, removing any old gasket material or sealant.
- Install the new gasket, wear plate, and woodruff key. Slide the new impeller onto the driveshaft, turning the shaft clockwise to bed the vanes correctly.
- Apply a light coat of marine grease to the inside of the new pump housing and install it over the impeller.
- Reinstall the lower unit, ensuring the water tube, driveshaft, and shift shaft align correctly. Bolt it securely.
- Reconnect the battery, start the engine in a water supply, and verify a strong, steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine model?
The most reliable method is to check your engine's model, year, and serial number against the Engine & Model Compatibility table. While this kit fits a wide range of engines, cross-referencing these details ensures a correct fit.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating at idle or low speeds, a weak or intermittent water stream from the tell-tale outlet, or a complete lack of water flow. A brittle, cracked, or deformed impeller is a clear sign it needs replacement.
How often should I replace my outboard's water pump impeller?
As a general maintenance rule, it is recommended to inspect and/or replace the water pump impeller annually or every 100 hours of operation, whichever comes first. This is especially important if you operate in saltwater or sandy/silty conditions.
Is there a difference in quality between this kit and an OEM part?
This is an aftermarket part designed to meet or exceed OEM specifications. It is manufactured using comparable materials, such as a neoprene impeller and stainless steel housing, to ensure reliable performance and durability without the OEM price.
Do I need any special sealants for the gaskets?
Generally, the included gaskets are designed to seal without additional sealant. However, a light, non-hardening sealant (like Permatex Aviation Form-A-Gasket) can be applied to the housing gaskets as a precaution against leaks, but avoid getting any on the impeller.
The kit includes multiple O-rings. Where do they all go?
This kit is designed for multiple engine variations, so you may have leftover parts. The main O-rings are for the pump housing and driveshaft seals. The two smallest O-rings are typically for the gear lube fill and vent screws on the lower unit.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. All our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available for your location.
Warranty & returns
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and 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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