Water Pump Impeller Repair Kit – Fits Mercury Marine 4–9.8 HP (Replaces 47-89981Q1, 47-89981T1, 47-89981T2)

Water Pump Impeller Repair Kit – Fits Mercury Marine 4–9.8 HP (Replaces 47-89981Q1, 47-89981T1, 47-89981T2)

This water pump impeller repair kit is designed for Mercury/Mariner 4, 4.5, 6, 7.5, and 9.8 HP 2-Stroke outboard engines manufactured between 1975 and 1986. Please verify your engine's serial number against the compatibility chart below to ensure a proper fit.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 47-89981Q1, 47-89981T1, 47-89981T2, Sierra 18-3239, GLM 12270, and Soxa Marine 18KM001.

• Complete kit includes a neoprene impeller, wear plate, seals, and o-rings for a full service.
• Features a durable 6-blade neoprene impeller with a brass hub for reliable performance.
• Designed for installation in the lower unit of the outboard motor.

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 Impeller (47-89981/18-3039)
• 1 x Wear Plate (46895)
• 1 x Key, Woodruff Impeller
• 1 x Sleeve, Guide Water Inlet Tube
• 1 x Seal (700-85651)
• 2 x O-ring (700-81230, 700-81090)

Installation Guide

1. Disconnect the battery and shift the outboard into neutral.
2. Remove the lower unit (gearcase) from the outboard housing.
3. Unbolt and remove the water pump housing to expose the old impeller.
4. Remove the old impeller, key, wear plate, and seals. Clean all gasket surfaces thoroughly.
5. Install the new wear plate, applying a light coat of marine grease to the interior surfaces.
6. Place the new Woodruff key on the driveshaft's flat spot.
7. Slide the new impeller onto the shaft, rotating the shaft clockwise to bed the blades correctly inside the housing.
8. Install new seals and o-rings on the housing where applicable.
9. Reinstall the water pump housing and tighten bolts to the manufacturer's specified torque.
10. Reattach the lower unit to the outboard, ensuring the water tube, driveshaft, and shift shaft are correctly aligned.

Troubleshooting & FAQ

How do I confirm this fits my engine?
Check your engine's serial number. This kit fits specific serial number ranges for Mercury/Mariner 4-9.8 HP models (1975-1986), as detailed in the compatibility chart. A critical dimension is the impeller's shaft diameter of 11.0 mm (0.456 inches). Please measure your old part if you are unsure.

Will this kit fit my 5 HP Mercury outboard?
No, this impeller kit is confirmed to NOT fit 5 HP Mercury/Mariner engines. Please review the compatible models list carefully.

What are the signs of a failing water pump impeller?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent stream of water from the "telltale" outlet, and a brittle or cracked appearance on the old impeller's blades upon inspection.

How often should I replace my impeller?
For preventative maintenance, it is recommended to inspect your impeller annually and replace it every 1-2 years, depending on usage (hours) and operating conditions (saltwater vs. freshwater). Do not wait for it to fail.

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.