47-89981 Water Pump Impeller for Mercury Mariner 4HP 4.5HP 6HP 7.5HP 9.8HP | JLM Marine

Water Pump Impeller for Mercury Mariner 4HP 4.5HP 6HP 7.5HP 9.8HP Outboard

This water pump impeller is designed to fit Mercury Mariner 2-stroke outboard engines ranging from 4HP to 9.8HP, manufactured between 1966 and 1978. It provides reliable cooling system performance for specific model series including 4, 45, 60, 60J, 75, 7.5, 110, and 9.8 engines within designated serial number ranges.

This impeller serves as a direct replacement for OEM part numbers 47-89981 and 47-65957, as well as aftermarket equivalents 12270 and 18-3239. Constructed from durable rubber and metal materials, it ensures stable operation and convenient installation for maintaining proper water flow through your outboard's cooling system.

• Inner diameter: 12mm (shaft 0.456")
• High-quality rubber and metal construction for durability
• Easy installation with proper tools

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

Your purchase includes:

• 1 x Outboard Impeller

Installation Guide

1. Disconnect the fuel line and remove the lower unit from the outboard engine following your service manual.
2. Remove the water pump housing bolts and carefully separate the housing to access the old impeller.
3. Note the orientation of the old impeller blades before removal. Pull out the old impeller from the shaft.
4. Clean the pump housing thoroughly, removing any debris, old gasket material, or corrosion.
5. Lubricate the new impeller with water-resistant grease or glycerin to ease installation and prevent dry-start damage.
6. Install the new impeller onto the shaft, ensuring the blades curve in the correct direction for proper water flow.
7. Replace the pump housing gasket with a new one (if included in your kit or purchased separately).
8. Reassemble the water pump housing, ensuring all components are properly aligned. Tighten bolts to manufacturer specifications.
9. Reinstall the lower unit onto the engine, ensuring proper gear engagement.
10. Reconnect the fuel line and refill the lower unit with the correct gear oil.
11. Test the cooling system by running the engine with water supply (using a test tank or muffs). Check for steady water stream from the telltale indicator.
12. Inspect for leaks around the pump housing and lower unit seals before operating at full throttle.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my Mercury Mariner engine?
A: Cross-reference your engine's horsepower, model number, and serial number with the compatibility table above. The serial number can be found on the transom bracket or swivel bracket of your outboard.

Q: How often should I replace my water pump impeller?
A: Most manufacturers recommend replacing the impeller every 2-3 years or 200-300 hours of operation, whichever comes first. If you frequently operate in sandy or debris-filled water, inspect and replace more often.

Q: What are the signs that my impeller is failing?
A: Common symptoms include weak or no water flow from the telltale (indicator stream), engine overheating, steam from the engine, or reduced performance. If you notice any of these signs, inspect and replace the impeller immediately.

Q: Can I install this impeller myself or do I need a professional?
A: If you have mechanical experience and the proper tools, you can install it yourself by following the service manual. However, if you're unfamiliar with lower unit disassembly, professional installation is recommended to avoid damage.

Q: What's the difference between this aftermarket impeller and the OEM version?
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.