Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957)

Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957)

This water pump impeller is designed for Mercury and Mariner 2-stroke outboard motors, including 4, 4.5, 6, 7.5, and 9.8 HP models. It also fits specific Johnson/Evinrude 20 HP models. Please verify your engine's model and serial number against the compatibility list below.

This component directly replaces Mercury part numbers 47-89981, 47-65957, and 47-39074, as well as several other aftermarket equivalents. Crucial Fitment Note: This impeller is for models with a 0.456-inch inside diameter drive shaft. It will NOT fit 5 HP Mercury/Mariner engines.

• Engineered with a durable neoprene impeller and a solid brass hub for corrosion resistance and longevity.
• Installation requires basic tools and should be performed as part of your scheduled lower unit maintenance.
• Package includes one water pump impeller.

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.

For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson Serial Number Guide.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 47-89981, 47-65957, 47-39074)

Explosion Diagram

Installation Guide

1. Disconnect the negative battery cable to prevent accidental starting.
2. Shift the outboard into neutral and remove the lower unit (gearcase) bolts. Carefully separate the lower unit from the upper housing.
3. Locate and unbolt the water pump housing cover. Take note of its orientation before removing.
4. Slide the old impeller off the driveshaft. Note the rotational direction of the existing blades if possible.
5. Thoroughly clean the inside of the pump housing and wear plate. Inspect for scoring, grooves, or corrosion.
6. Lightly lubricate the new impeller and the inside of the housing with marine grease.
7. Install the new impeller onto the driveshaft, turning the shaft in the direction of engine rotation to bend the blades correctly.
8. Reinstall the water pump housing and gasket, ensuring a proper seal. Torque bolts to manufacturer specifications.
9. Reattach the lower unit to the engine, making sure the driveshaft, shift shaft, and water tube are correctly aligned.
10. Once assembled, reconnect the battery and test the engine using a water supply (flushing muffs) to confirm water is pumping correctly.

Troubleshooting & FAQ

How do I confirm this fits my engine?
The most critical factor is the driveshaft diameter. This impeller fits a 0.456-inch shaft. Many Mercury models used different shafts, so please check the model/serial number information in the compatibility table above. Do not purchase if your engine is not listed or if your shaft size is different.

Will this fit my 5 HP Mercury engine?
No. This impeller is specifically noted by manufacturers to NOT fit 5 HP Mercury or Mariner engines, as they typically use a different water pump and impeller design.

How often should I replace the water pump impeller?
For preventative maintenance, most manufacturers recommend replacing the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This can vary based on usage conditions (e.g., saltwater vs. freshwater, sandy/silty water).

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.