Water Pump Impeller – Fits Mercury 3.9-9.8 HP Outboards (Replaces 47-89981)

Water Pump Impeller – Fits Mercury 3.9-9.8 HP Outboards (Replaces 47-89981)

This aftermarket water pump impeller is designed for Mercury 1-cylinder outboards, including 4 HP (1982-1985), 4.5 HP (1980-1985), 7.5 HP (1979-1986), and 9.8 HP (1979-1985) 2-Stroke models. It is built specifically for engines that use a 0.456" diameter driveshaft.

It serves as a direct replacement for Mercury OEM parts 47-89981, 47-89981Q1, 47-89981T1, and 47-89981T2, as well as other aftermarket equivalents, ensuring reliable performance for your engine's cooling system.

• Material: Constructed from durable neoprene rubber with a solid brass hub to resist corrosion in marine environments.
• Critical Fitment: Intended only for models with the 0.456" outer diameter driveshaft. Please verify your engine's requirements before purchase.
• Package Includes: 1 x 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.

Technical Specifications

Package Contents

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

Installation Guide

1. Disconnect the negative battery cable and shift the outboard into the neutral position.
2. Locate and unbolt the lower unit (gearcase) from the engine's driveshaft housing.
3. Carefully lower and separate the gearcase to expose the water pump assembly.
4. Remove the bolts on the water pump housing cover to access the old impeller.
5. Take note of the blade orientation of the old impeller before pulling it off the driveshaft.
6. Clean any dirt or corrosion from the pump housing and inspect the wear plate and housing for damage.
7. Slide the new impeller onto the driveshaft, ensuring the blades are bent in the correct rotational direction (usually clockwise).
8. Reinstall the water pump housing cover and its gasket, tightening the bolts to the specified torque.
9. Reattach the lower unit to the upper engine casing, ensuring the driveshaft and water tube align correctly.

Troubleshooting & FAQ

Q: How do I know if this impeller fits my Mercury engine?

A: This impeller is specifically for Mercury models from 3.9 HP to 9.8 HP that have a 0.456-inch diameter driveshaft. Please measure your driveshaft or verify your OEM part number is 47-89981 before ordering. It is crucial to confirm this dimension, as a different impeller exists for other models.

Q: Will this fit my 5 HP Mercury outboard?

A: No, this part will not fit 5 HP Mercury/Mariner engines, which typically require part number 47-16154-3.

Q: What are the signs that my water pump impeller needs replacing?

A: Common signs include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, or visible damage such as cracked, stiff, or broken blades on the existing impeller.

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.