Water Pump Impeller Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 47-89980T1)

Water Pump Impeller Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 47-89980T1)

This water pump impeller kit is designed for Mercury/Mariner 2-stroke outboard engines from 3.9 HP to 9.8 HP, model years 1979–1986, specifically those requiring an impeller with a 0.438" (11.13 mm) inner diameter. It serves as a direct replacement for the original equipment, ensuring proper fit and function for cooling system maintenance.

Engineered to meet OEM specifications, this kit provides a reliable solution for replacing worn or damaged water pump components, helping to prevent engine overheating and maintain performance. This is an aftermarket replacement part.

• Installation Method: Direct replacement
• Impeller Material: Durable neoprene rubber
• Key Components: Includes impeller, wear plate, sleeve, O-rings, and seal

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

This kit includes the following components:

• 1 x Sleeve (700-12963)
• 1 x Impeller (700-89800)
• 1 x Wear Plate (700-12560)
• 1 x O-Ring (700-81230)
• 1 x O-Ring (700-81090)
• 1 x Seal (700-85651)

Installation Guide

1. Disconnect the battery and spark plug wires for safety.
2. Place the outboard in neutral and remove the lower unit (gearcase) bolts.
3. Carefully lower and separate the gearcase from the engine.
4. Unbolt and remove the water pump housing cover to access the impeller.
5. Remove the old impeller, wear plate, gaskets, and seals. Note their orientation.
6. Clean the housing interior and mating surfaces thoroughly.
7. Install the new O-rings, seal, wear plate, and sleeve from the kit.
8. Seat the new impeller into the housing, turning the driveshaft clockwise to bend the vanes correctly.
9. Reinstall the water pump housing and tighten the bolts to the manufacturer's torque specifications.
10. Re-attach the lower unit to the engine, ensuring all shafts and tubes align correctly.
11. Reconnect the battery and spark plugs. Start the engine and verify a steady water stream from the tell-tale.

Troubleshooting & FAQ

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

A: The best way is to verify your engine's model, horsepower, and year against our compatibility table. Most importantly, check the serial number range listed in the "Notes" column. This kit is for engines requiring an impeller with a 0.438-inch inner diameter.

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

A: Common signs include the engine overheating, an alarm sounding (if equipped), or a weak or non-existent water stream from the "tell-tale" outlet. Reduced engine performance can also be an indicator.

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

A: For preventative maintenance, it is recommended to replace the impeller every 1 to 2 years or every 100-200 hours of operation, whichever comes first. The interval may be shorter if you operate in sandy, silty, or saltwater 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.