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

Water Pump Impeller Repair Kit – Fits Mercury/Mariner 8-25 HP Outboards

This comprehensive water pump repair kit is designed for a wide range of Mercury and Mariner outboard motors, including 2-Stroke 15-25 HP engines (1980-1998) and select 4-Stroke 8-15 HP Bigfoot models (1998 and newer). It provides the necessary components to service or rebuild your engine's water pump for reliable cooling performance.

This kit is a direct replacement for Mercury part numbers 99157T2, 46-99157T2, 46-99157A2, 46-85098A2, 85098A2, and 99157A2.

• Complete Kit: Includes a new impeller, housing, plates, gaskets, seals, and all necessary hardware for a full rebuild.
• Durable Materials: Features a robust SS316 stainless steel housing and a high-performance neoprene rubber (CR) impeller for longevity.
• Direct Installation: Engineered to match OEM specifications for a direct fit and hassle-free installation.

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 (46-99157A02)
• 1 x Gasket (27-993261)
• 1 x Plate (85083)
• 1 x Impeller (Replaces 47-85089-3, 47-85089-10, 8M0024502)
• 1 x Key (8M0032838)
• 3 x O-rings
• 4 x Insulator (23-85095)
• 1 x Water Tube Guide Sleeve
• 2 x Gear Lube Fill and Vent Screw O-rings
• 2 x Face Plates
• 2 x Washers (transparent, 12-86645-1)
• 1 x Seal (85090/85090001)

Installation Guide

1. Safety First: Before starting, disconnect the battery and ensure the engine is in a stable, secure position.
2. Access the Lower Unit: Drain the gearcase oil. Unbolt and carefully remove the lower unit (gearcase) from the outboard's driveshaft housing.
3. Remove Old Pump: Locate the water pump housing, typically on top of the gearcase. Unbolt and remove the old housing and impeller assembly.
4. Clean and Inspect: Thoroughly clean the mounting surfaces, removing any old gasket material or corrosion. Inspect the driveshaft for wear or damage.
5. Install New Components: Lightly grease the new O-rings and seals. Install the new key, impeller (rotate clockwise when seating), gaskets, and wear plates as per the kit's components.
6. Seat the Housing: Apply a light lubricant inside the housing cup. Carefully slide the new housing down over the impeller, ensuring a proper seal.
7. Reassemble: Bolt the new housing back onto the lower unit, tightening bolts to the manufacturer's specified torque. Reattach the lower unit to the engine.
8. Final Checks: Refill the gearcase with fresh lubricant. Reconnect the battery. Start the engine in a water source and check for a steady stream of water from the tell-tale port.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific Mercury or Mariner engine?
A: The most reliable method is to use your engine's serial number. The compatibility table above lists the applicable serial number ranges for each model. You can find help locating your number with our Mercury Serial Number Guide and cross-reference the required OEM part number, which should be 99157T2 or a superseded version.

Q: What are the signs that my water pump impeller needs to be replaced?
A: Common signs of a failing impeller include a weak or intermittent water stream from the "tell-tale" outlet, engine overheating alarms, and visible cracks or stiffness in the old impeller's rubber vanes upon inspection.

Q: How often should the water pump impeller be replaced?
A: As a general maintenance rule, it is recommended to inspect and/or replace the water pump impeller every 1-2 years or every 100-200 hours of use, depending on operating conditions (saltwater vs. freshwater). Proactive replacement prevents engine damage from overheating.

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.