Water Pump Impeller Kit – Fits Mercury/Mariner 9.9-25 HP (Replaces 46-99157T2, 85098A2, 99157A2)

Water Pump Impeller Kit – Fits Mercury/Mariner 9.9-25 HP (Replaces 46-99157T2, 85098A2, 99157A2)

This water pump impeller repair kit is a direct-fit replacement for Mercury and Mariner outboard engines, including 2-Stroke models from 15–25 HP (1980–1997) and 4-Stroke models from 9.9–15 HP (specifically BigFoot models). It is designed to restore cooling system performance for popular 18 HP, 20 HP, and Sea Pro/Marathon models.

Engineered to meet or exceed original equipment specifications, this kit provides a reliable solution for maintaining your outboard's cooling system. It directly replaces Mercury part numbers 46-99157T2, 99157T2, 85098A2, and 99157A2, as well as aftermarket equivalents.

• Installation Type: Direct OEM-fit replacement requires no modifications.
• Core Components: Includes the pump housing, impeller, wear plate, gaskets, and all necessary seals and hardware.
• Quality Manufacturing: Produced in an ISO9002 certified factory to ensure consistent quality and performance.

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 Pump Housing Assembly (99157T2)
• 1 x Impeller (47-85089-3/47-85089-10)
• 2 x Impeller Washer (8M0027721)
• 1 x Impeller Key (8M0032838)
• 1 x Pump O-Ring (69202)
• 1 x Wear Plate (85083)
• 1 x Pump Gasket (85087/27-993261)
• 1 x Seal (85090001)
• 4 x Bushing (85095)
• Multiple O-rings, screws, and washers

Explosion Diagram

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is securely mounted.
2. Access the Pump: Remove the lower unit (gearcase) from the outboard's midsection.
3. Remove Old Housing: Unbolt and carefully lift the old water pump housing off the driveshaft.
4. Extract Old Parts: Remove the old impeller, woodruff key, wear plate, and any gaskets or O-rings. Note their orientation.
5. Clean Surfaces: Thoroughly clean the mating surfaces on the gearcase and driveshaft, removing any old gasket material or corrosion.
6. Install New Gaskets & Plate: Place the new gaskets and wear plate into position.
7. Install New Impeller: Lightly lubricate the inside of the housing and the impeller with marine grease. Slide the new woodruff key and impeller onto the driveshaft, rotating the shaft clockwise to seat the impeller vanes correctly inside the housing.
8. Secure New Housing: Press the new housing down, ensuring a proper seal. Insert and tighten the mounting bolts to the manufacturer's specified torque.
9. Reassemble & Test: Reinstall the lower unit, reconnect the battery, and attach a reliable water supply. Start the engine and verify a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this impeller kit fits my specific engine?

A: The most reliable method is to match your engine's model or serial number to our compatibility chart. For Mercury engines, the serial number is typically on a tag on the transom bracket. Use our Mercury Serial Number Guide to help locate it and confirm fitment.

Q: What are the common symptoms of a failing water pump impeller?

A: Key indicators include a weak or no water stream from the "tell-tale" outlet, an engine overheating alarm, or a noticeable decrease in cooling performance. Upon inspection, a worn impeller may appear cracked, brittle, or have missing vanes.

Q: How often should I replace the water pump impeller?

A: For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of engine use. Replacement intervals should be shorter in saltwater or silty/sandy conditions.

Q: OEM vs. Aftermarket?

A: 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.

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

A: 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.

Q: What is your warranty and return policy?

A: 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.