Water Pump Repair Kit for Mercury and Mariner Outboards – 2-Stroke 15–25 HP and 4-Stroke 9.9–15 HP
Water Pump Repair Kit for Mercury and Mariner Outboards – 2-Stroke 15–25 HP and 4-Stroke 9.9–15 HP 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.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Water Pump Repair Kit for Mercury and Mariner Outboards – 2-Stroke ...
Water Pump Repair Kit for Mercury and Mariner Outboards – 2-Stroke 15–25 HP and 4-Stroke 9.9–15 HP is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit is an aftermarket replacement for selected Mercury and Mariner outboards, including 2-stroke 15–25 HP models and 4-stroke 9.9–15 HP BigFoot models. It also covers selected Force 25 HP and Sears Gamefisher 25 HP 2-stroke applications. Always verify the complete engine model, year, stroke, and serial-number range before ordering.
This kit is listed as a replacement or cross-reference for Mercury part numbers 99157T2, 46-99157T2, 85098A2, 99157A2, and 46-85098A2, and Quicksilver part number 85089Q4.
- Complete upper water-pump service kit for applicable outboard lower units.
- Includes the impeller, pump housing, face plate, gaskets, seal, key, washers, insulators/grommets, and O-rings listed below.
- Aftermarket replacement components intended for freshwater and saltwater service when installed and maintained correctly.
Part Number Matrix
Use these manufacturer and aftermarket references to compare the kit with the parts removed from your engine. These references do not replace model, year, stroke, and serial-number verification.
| Brand | Part Number |
|---|---|
| Mercury | 99157T2 / 46-99157T2 |
| Mercury | 85098A2 / 99157A2 / 46-85098A2 |
| Quicksilver | 85089Q4 |
Engine and Model Compatibility
The applications below are the listed fitment scope for this replacement kit. Confirm the engine model, horsepower, stroke, year, and serial number before purchase. A number appearing in a parts catalog alone does not confirm fitment outside the conditions shown here.
| Brand | Model | Rated HP | Stroke | Years | Reference | Serial or Model Notes |
|---|---|---|---|---|---|---|
| Mercury | BigFoot | 9.9 (323cc) | 4-Stroke | 1998–2005 | 99157T2 | USA serial 0G760300–0T979999; BEL serial 0P075166–0P325499 |
| Mercury | BigFoot | 15 (323cc) | 4-Stroke | 1998 | 99157T2 | USA serial 0G590000 and up; BEL serial 9973100 and up |
| Mercury | XD, BigFoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | BEL serial 9927000 and up |
| Mercury | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2 | USA serial 5837437 and up; AUS serial 8071973 and up; BEL serial 9308306 and up |
| Mercury | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2 | USA serial 6443973–0T800749; BEL serial 9415101 and up; CAN serial 7209533 and up |
| Mercury | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 99157T2 | USA serial 5705532 and up; AUS serial 8073158 and up |
| Mercury | 25 3-Cylinder | 25 | 2-Stroke | 1997 and up | 99157T2 | USA serial 0E268781 and up |
| Mercury | 25 Sea Pro, Marathon, Super 15 | 25 | 2-Stroke | 1988–1998 | 99157T2 | USA serial 0B238464 and up; BEL serial 9507381 and up; CAN serial 0A730007 and up |
| Mariner | BigFoot | 9.9 (323cc) | 4-Stroke | 1998–2005 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | BigFoot | 15 (323cc) | 4-Stroke | 1998 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 15 XD, BigFoot | 15 | 2-Stroke | 1997–1998 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 18, 18XD | 18 | 2-Stroke | 1980–1985 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 20, 20XD | 20 | 2-Stroke | 1986–1987 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 25, 25XD | 25 | 2-Stroke | 1980–1987 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 25 3-Cylinder | 25 | 2-Stroke | 1997 and up | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Mariner | 25 Sea Pro, Marathon, Super 15 | 25 | 2-Stroke | 1988–1998 | 99157T2 | Verify the corresponding Mercury-derived serial range |
| Force | 25 | 25 | 2-Stroke | 1994–1998 | 99157T2 | Includes model codes such as H025201RD [MH] and H025211RD [MLH] |
| Sears | Gamefisher 25 | 25 | 2-Stroke | 1994–1998 | 99157T2 | Includes models 225.582500 and 225.592500 |
Technical Specs
- Product Type
- Upper water pump repair kit
- Installation
- Replacement for the applicable original water-pump assembly
- Fuel Type
- Gasoline outboard applications
- Housing Material
- Stainless steel and plastic components
- 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)
- Service Position
- Upper water-pump components in the lower unit
What's in the Box
- 1 x Water pump impeller — 47-85089-3, 47-85089-10, or 8508910 reference
- 1 x Pump housing assembly — 99157A02 or 99157A1 reference
- 1 x Face plate — 85083 reference
- 1 x Gasket — 993261 reference
- 1 x Key — 8M0032838 reference
- 1 x Seal — 85090 or 85090001 reference
- 2 x Washer — 12-86645-1 reference
- 4 x Insulator/grommet — 23-85095 reference
- 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 if the gearcase lubricant must be drained during service.
- Remove the fasteners securing the lower unit to the driveshaft housing.
- Carefully lower and separate the gearcase, taking care around the shift shaft and water tube.
- Remove the old water-pump housing, impeller, face plate, gaskets, seal, and related components.
- Clean the driveshaft and all mating surfaces. Remove gasket residue, debris, and corrosion without damaging the sealing surfaces.
- Install the new key and impeller on the driveshaft, then install the face plate, gaskets, seal, and pump housing in the correct order for the engine.
- Lightly lubricate the appropriate O-rings and the inside of the pump cup with a suitable marine lubricant. Do not install a neoprene impeller dry.
- Tighten the pump-housing fasteners to the engine manufacturer's specified torque.
- Reinstall the lower unit, ensuring that the driveshaft, shift shaft, and water tube are correctly aligned.
- Refill the gearcase with the correct marine gear lubricant if it was drained.
- Run the engine only in water or with an appropriate flushing attachment, and verify a steady tell-tale stream before normal operation.
Troubleshooting and FAQ
How do I know if my water pump is failing?
Common signs include a weak or absent tell-tale stream, an overheating warning, reduced cooling-water flow, or a damaged, brittle, cracked, or deformed impeller found during inspection.
How often should I replace the water-pump impeller?
Replacement intervals depend on use, storage, water conditions, and the engine manufacturer's maintenance schedule. Many operators replace an impeller every one to two years or at the recommended service-hour interval, with more frequent inspection in saltwater or debris-heavy conditions.
Will this kit fit an engine whose serial number is not listed?
Do not assume compatibility when the serial number is outside the ranges shown. Compare the original water-pump part numbers and consult the applicable engine parts catalog or a qualified marine technician before ordering.
Is this an OEM kit?
No. This is an aftermarket replacement kit. Mercury, Mariner, Force, Sears, Quicksilver, and other referenced names and part numbers are used only to identify applicable engines or replacement references.
Do I need special tools for installation?
Basic hand tools are typically required. A torque wrench is recommended so the pump-housing and lower-unit fasteners can be tightened to the manufacturer's specifications.
Is lubricant required during installation?
Use a suitable marine lubricant on O-rings and appropriate assembly surfaces. Do not start the engine with a dry impeller, and follow the engine manufacturer's instructions for initial priming and lubrication.
How fast do you ship?
Typical transit is 5–15 days. Standard shipping is free, and expedited options appear at checkout where available.
What is the warranty and return policy?
Parts are covered by a 1-year warranty against manufacturing defects under normal use. Returns are accepted within the standard return window for unused items in their original condition. Contact support with your order details for warranty or return instructions.
Safety and Important Information
- Verify the engine brand, model, horsepower, stroke, year, serial number, and original part number before purchase.
- Compare the supplied components with the original assembly before installation. Do not operate the engine if any component, seal, or fastener is missing or incorrectly installed.
- This is an aftermarket replacement part, not an OEM component. Referenced brand names and part numbers identify compatibility only.
- Professional installation is recommended. Incorrect water-pump installation can cause insufficient cooling and severe engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for reliable fit and service performance.
- Fast Global Fulfillment — Standard delivery is available to most regions, with typical transit of 5–15 days.
- Manufacturer-Direct Value — We work with manufacturing partners to provide replacement parts at competitive prices.
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