Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP Outboard Engines

Water Pump Impeller Kit – Fits Mercury/Mariner/Force 8-25 HP Outboard Engines (Replaces 99157T2, 46-99157T2)

This water pump impeller kit provides a complete solution for servicing and rebuilding the lower unit water pump on a wide range of Mercury, Mariner, and Force outboard engines. It is designed for 8-25 HP 2-Stroke models from 1984-2005, ensuring reliable cooling system performance.

This kit serves as a direct replacement for Mercury OEM part numbers 99157T2, 85098A2, and 99157A2. It is also cross-compatible with Sierra 18-3214 and Recmar REC46-99157T2.

• Includes a neoprene impeller, wear plate, gasket, and complete pump housing.
• Installs in the lower unit of the outboard.
• Designed for use with gasoline engines.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 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 Guide

1. Disconnect Power: Disconnect the spark plug wires and the negative battery terminal for safety.
2. Drain Gear Lube: Place a drain pan under the lower unit and remove the drain/fill screws to empty the gear lube.
3. Remove Lower Unit: Remove the bolts securing the lower unit to the midsection. Carefully separate the assembly.
4. Access Pump: Unbolt and remove the old water pump housing to expose the impeller and wear plate.
5. Clean Surfaces: Thoroughly clean the driveshaft and all mating surfaces, removing any old gasket material or sealant.
6. Install New Components: Place the new gasket and wear plate onto the lower unit. Slide the new impeller onto the driveshaft, ensuring the keyway is aligned.
7. Install Housing: Lubricate the inside of the new pump housing and install it over the impeller, turning the driveshaft clockwise to help seat the vanes.
8. Secure and Reassemble: Fasten the new pump housing. Reinstall the lower unit, making sure the driveshaft, shift shaft, and water tube align correctly.
9. Final Checks: Refill the lower unit with marine gear lube. Reconnect the battery and spark plug wires.
10. Test Operation: Using a water source (like flushing muffs), start the engine and verify a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?

Check your engine's model, HP, and year against the compatibility table. This kit fits 8-25 HP Mercury, Mariner, and Force 2-stroke outboards from 1984-2005. Verifying your engine's part number against the cross-reference list (99157T2, 85098A2, etc.) is the best way to ensure a match.

How often should I replace the water pump impeller?

As a general maintenance guideline, inspect the impeller annually and replace it every 1-2 years or 100-200 hours of operation, whichever comes first. If you frequently operate in sandy, silty, or saltwater, more frequent inspections and replacements are recommended.

What are the symptoms of a failing impeller?

Common signs of a worn or damaged impeller include a weak or intermittent water stream from the "tell-tale" cooling outlet, engine overheating alarms, or a reduction in engine performance. Upon inspection, a bad impeller may have cracked, brittle, or deformed vanes.

OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.