Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP (Replaces 99157T2, 46-99157T2)
Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP (Replaces 99157T2, 46-99157T2) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP (Repla...
Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP (Replaces 99157T2, 46-99157T2) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP Outboard Engines is a crucial replacement part for maintaining your engine's cooling system. It is designed for a precise fit on a wide range of Mercury, Mariner, and Force 8–25 HP 2-stroke outboard engines manufactured from 1984 to 2005, ensuring reliable performance and preventing engine overheating.
This kit serves as a direct interchange for Mercury part numbers 99157T2, 85098A2, and 99157A2, as well as Sierra 18-3214.
- Installation Location: Mounts in the lower unit of the outboard engine.
- Essential Components: Includes a durable neoprene impeller, wear plate, gasket, and the complete pump housing for a comprehensive service.
- Warranty Protection: Comes with a 1-year warranty for peace of mind against manufacturing defects.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Mercury | 99157T2 | Current OEM part number. | |
| Mercury | 99157A2 | 99157T2 | |
| Mercury | 85098A2 | 99157A2 | |
| Sierra | 18-3214 | Aftermarket cross-reference. |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner engines, this kit fits various 2-stroke models from 8 HP to 25 HP manufactured between 1984 and 2005.
For Force engines, this kit is compatible with 25 HP 2-stroke models from 1995 to 1998, specifically the H025201 and H025211 series.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 8, 9.9, 13.5, 15, 18, 20, 25 | 8–25 HP | 2-Stroke | 1984–2005 | 99157T2 | Superseded 99157A2, 85098A2 |
| Mariner | 8, 9.9, 13.5, 15, 18, 20, 25 | 8–25 HP | 2-Stroke | 1984–2005 | 99157T2 | Superseded 99157A2, 85089A2 |
| Force | 25 | 25 HP | 2-Stroke | 1995–1998 | 99157T2 | Models H025201 / H025211 series |
Technical Specs
- Product Type
- Water Pump Impeller Kit with Housing
- Installation
- Lower Unit
- Fuel Type
- Gasoline
- Included Components
- Neoprene impeller, wear plate, gasket, and pump housing
- Warranty
- 1 Year (from Marine-Parts eBay seller)
What’s in the Box
- 1 x Water Pump Kit with Housing (Replaces 99157T2 / 46-99157T2)
- 1 x Neoprene Impeller (Replaces 47-85089-3 / 47-85089-10)
- 1 x Wear Plate (Replaces 85083)
- 1 x Gasket (Replaces 27-993261)
- 1 x Pump Housing (Replaces 46-99157A02)
Installation Notes
- Disconnect the battery and shift the outboard into the neutral position.
- Remove the bolts securing the lower unit (gearcase) and carefully lower it from the engine.
- Locate and unbolt the water pump housing, which sits atop the gearcase.
- Remove the old housing, impeller, wear plate, and any gasket remnants.
- Thoroughly clean all mating surfaces to ensure they are free of old gasket material and corrosion.
- Install the new wear plate and gasket onto the gearcase.
- Slide the new impeller onto the driveshaft and into the new housing, turning the driveshaft clockwise to seat the impeller vanes correctly.
- Lightly lubricate the interior of the housing with marine grease.
- Position the new housing assembly and tighten the bolts to the manufacturer's specified torque.
- Carefully reinstall the lower unit, ensuring the driveshaft, water tube, and shift shaft are properly aligned.
- Once secured, reconnect the battery and test the engine in water, confirming a steady water stream from the cooling system's tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump is failing?
Common signs include an engine overheating alarm, a weak or non-existent stream of water from the tell-tale outlet, and discovering a cracked, brittle, or worn impeller during inspection.
What is the recommended replacement interval for this kit?
For optimal engine protection and to prevent overheating, boat owners should inspect the impeller annually and replace it every 1 to 2 years (or every 100-200 hours of use), whichever comes first. Frequency should increase in silty or saltwater environments.
Will this fit a 4-stroke engine model?
No, this particular water pump kit is engineered specifically for the 2-stroke Mercury, Mariner, and Force outboard models listed in the compatibility table. It is not compatible with 4-stroke engines.
Does this kit include the outer housing?
Yes, this is a complete water pump rebuild kit that includes the pump housing, neoprene impeller, wear plate, and the required gasket for a full replacement.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9001 certified 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 and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is strongly recommended for safety, proper function, and engine performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- 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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