Water Pump Impeller – Fits Mercury Marine 65-300 HP Outboards (Replaces 47-89984T4, 18-3017)

Water Pump Impeller – Fits Mercury Marine 65-300 HP Outboards (Replaces 47-89984T4, 18-3017)

This water pump impeller is designed for a wide range of Mercury Marine 2-stroke outboard engines from 65 HP to 300 HP, manufactured from the 1980s through the 2000s. It also fits select Force/Chrysler 85-150 HP outboard engines.

Engineered to meet or exceed OEM specifications, this impeller serves as a direct replacement for Mercury part numbers 47-30221, 47-89984, 47-89984T3, and 47-89984T4, as well as aftermarket parts like Sierra 18-3017, GLM 89840, and Mallory 9-45306.

• Installation Type: Direct OEM replacement for straightforward installation.
• Material: Constructed from durable, high-quality neoprene with a metal alloy hub for reliable performance.
• Package Includes: Water pump impeller and a new drive key.

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 Force/Chrysler engines, confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (47-89984T4)
• 1 x Key (28-56654)

Installation Guide

A typical impeller replacement involves the following steps. Professional installation is always recommended.

1. Safety First: Disconnect the battery and ensure the engine is securely mounted.
2. Access the Lower Unit: Drain the gearcase oil and remove the lower unit (gearcase) from the outboard.
3. Remove Pump Housing: Unbolt and carefully lift the water pump housing to expose the old impeller.
4. Inspect Old Impeller: Note the rotational direction of the existing impeller's blades before removal.
5. Remove Old Parts: Slide the old impeller off the drive shaft and remove the old drive key.
6. Clean and Inspect: Thoroughly clean the pump housing, wear plate, and all surfaces. Check for deep grooves or warping, which indicate the housing should also be replaced.
7. Install New Impeller: Place the new key in its slot on the driveshaft. Slide the new impeller on, rotating the driveshaft clockwise to help fold the blades into the correct position as you lower the housing.
8. Reassemble: Reinstall the water pump housing, ensuring any gaskets and seals are correctly seated. Torque bolts to manufacturer specs.
9. Reattach Lower Unit: Reinstall the lower unit and refill the gearcase with fresh oil.
10. Test Operation: Connect a water supply (flushing muffs) to the engine, start it, and verify that water is exiting the "tell-tale" port, indicating the pump is working.

Troubleshooting & FAQ

How do I confirm this fits my Mercury engine?
For Mercury engines, the most reliable way to confirm fitment is by checking your engine's serial number against the ranges listed in the compatibility table. Year and model alone can sometimes be misleading.

What are the signs of a failing water pump impeller?
Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, the engine overheating at idle or low speeds, and a melted water pump housing. The flexible neoprene blades can wear down, break, or become stiff with age.

How often should I replace the impeller?
As a general rule, it is recommended to inspect your water pump impeller annually and replace it every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can be shorter if you frequently operate in sandy or debris-heavy 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.