Water Pump Impeller Repair Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 46-92970A5, 47-89980T1)

Water Pump Impeller Repair Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 46-92970A5, 47-89980T1)

This water pump impeller repair kit is designed for Mercury/Mariner 2-stroke outboard models, including 3.9, 4, 4.5, 6, 7.5, and 9.8 HP engines manufactured between 1975 and 1986. It is critical that your engine requires the 0.438" impeller insert size for correct fitment.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, providing all the necessary components to restore your engine's cooling system to factory specifications.

• The complete kit includes a durable marine-grade nylon PA66 water pump housing, a stainless steel SS316 wear plate and liner, a high-performance impeller, and all necessary gaskets, seals, and O-rings for a comprehensive service.
• Engineered for direct installation in the lower unit gearcase.
• Crucial Specification: The included impeller features an insert size of 0.438 inches (11.13 mm). Please verify this dimension on your existing part before ordering to ensure compatibility.

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 Housing
• 1 x Cover Assembly
• 1 x Face Plate (Wear Plate)
• 1 x Water Pump Impeller (47-89980T1)
• 1 x Cup Insert
• 1 x Key (Woodruff Impeller)
• 1 x Seal
• 2 x O-Ring
• 1 x Rubber Ring
• 1 x Oil Seal/O-Ring
• 1 x Washer

Installation Guide

1. Disconnect the negative battery cable and shift the outboard into the neutral position.
2. Remove the lower unit (gearcase) by unbolting it from the engine's midsection and disconnecting the shift linkage rod.
3. Place the lower unit on a suitable workbench. Remove the bolts securing the old water pump housing and lift it off the driveshaft.
4. Carefully note the order of all components. Remove the old impeller, Woodruff key, wear plate, and any seals or gaskets still in place.
5. Thoroughly clean the driveshaft and the pump mounting surface, ensuring all old gasket material and corrosion are removed.
6. Install the new wear plate and gasket onto the gearcase, ensuring they align correctly.
7. Slide the new Woodruff key into its designated slot on the driveshaft.
8. Install the new impeller by sliding it onto the driveshaft. Rotate the shaft clockwise while pushing down to seat the impeller correctly over the key.
9. Apply a thin coat of marine grease or a soap/water solution to the inside of the new pump housing and install it over the impeller.
10. Replace all seals and O-rings as supplied in the kit. Securely tighten the housing bolts to the manufacturer's specified torque.
11. Re-install the lower unit onto the midsection, carefully reconnecting the shift linkage and water tube.
12. Reconnect the battery. Before launching, use a water source (like flushing muffs) to start the engine and confirm there is a strong, steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific engine?
A: The most reliable method is to match your engine's serial number to the ranges listed in the "Compatible Engine Models" table above. It is also critical to confirm that your original impeller has a 0.438-inch insert size, as some similar models used different variants.

Q: What are the signs of a failing water pump impeller?
A: Common symptoms include a weak or non-existent water stream from the "tell-tale" cooling outlet, an engine overheating alarm sounding, or steam from the exhaust. A damaged or worn impeller cannot effectively pump water to cool the engine, leading to overheating.

Q: How often should I replace my water pump impeller?
A: For preventative maintenance, it is recommended to inspect and/or replace the impeller every 1-2 years or every 100-200 hours of operation. If you frequently operate in sandy, silty, or saltwater, more frequent replacement is advised.

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.