Water Pump Impeller Kit – Fits Mercury/Force/Mariner 18-25 HP (Replaces 47-85089T7, 47-85089Q4)

Water Pump Impeller Kit – Fits Mercury/Force/Mariner 18-25 HP (Replaces 47-85089T7, 47-85089Q4)

This water pump impeller repair kit is designed for Mercury/Mariner 2-stroke outboard engines from 15 HP to 25 HP (model years 1983–2006) and Force 2-stroke outboards from 18 HP to 25 HP.

It serves as a direct replacement for Mercury part numbers 47-85089T7 and 47-85089Q4, as well as the Sierra aftermarket equivalent 18-3215.

• Installation: Direct OEM-style replacement.
• Compatibility: Fits a wide range of Mercury, Mariner, and Force outboards.
• Warranty: The Sierra equivalent part comes with a Limited Lifetime Warranty.

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 Impeller Kit (Replaces 47-85089T7/47-85089Q4)

Explosion Diagram

Installation Guide

1. Disconnect the battery and ensure the engine is in neutral.
2. Remove the lower unit bolts and carefully detach the lower unit from the engine.
3. Locate and unbolt the water pump housing.
4. Remove the old impeller, gasket, and wear plate, noting their orientation.
5. Clean all housing and mating surfaces thoroughly, removing any old gasket material or debris.
6. Install the new gasket, wear plate, and impeller. Ensure the impeller vanes are oriented correctly.
7. Lubricate the inside of the housing and the new impeller with a marine-grade grease.
8. Reinstall the water pump housing and tighten bolts to the manufacturer's specified torque.
9. Carefully guide the driveshaft and water tube back into position and reattach the lower unit.
10. Reconnect the battery and test the engine with a water supply to ensure proper water flow.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This kit is designed for Mercury/Mariner 2-stroke outboards (15–25 HP, 1983–2006) and Force 2-stroke outboards (18–25 HP). Please check the "Compatible Engine Models" table and cross-reference your engine's part number with Mercury 47-85089T7, 47-85089Q4, or Sierra 18-3215.

What are the signs I need to replace my water pump impeller?
Common signs of a failing impeller include the engine overheating, a weak or non-existent water stream from the "tell-tale" outlet, or visible cracks and brittleness on the old impeller's vanes during inspection.

How often should the impeller be replaced?
For preventative maintenance, 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 (e.g., saltwater vs. freshwater).

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.