Water Pump Impeller – Fits Mercury/Mariner/MerCruiser 30-300 HP (Replaces 47-89984T4)

Water Pump Impeller – Fits Mercury/Mariner/MerCruiser 30-300 HP (Replaces 47-89984T4)

This water pump impeller is designed for a wide range of Mercury/Mariner 2-stroke outboard engines from 30-300 HP (1961–2006), MerCruiser MC-I and Alpha One sterndrives (1983-1990), and various Force 75-150 HP 2-stroke outboards. It serves as a direct replacement, ensuring reliable cooling system performance.

Engineered to meet OEM specifications, this impeller directly replaces Mercury part numbers 47-89984T4, 47-89984T3, 47-89984, 47-899844, 47-899843, 47-899842, 47-899841, 47-803631T, 47-8M0028376, 47-65960, 47-85460, and 47-30221, among others.

• Installation Method: Direct replacement for a straightforward installation.
• Material: Constructed from durable neoprene rubber with a metal alloy insert for longevity.
• Compatibility: Fits standard, Alpha One, MC-I, and MR gear case housings.

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.

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

Confirm your engine model/year in the table below.

Mercury / Mariner

MerCruiser

OMC / Johnson / Evinrude

Force

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 47-89984T4)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is securely tilted.
2. Drain Lower Unit: Place a drain pan under the lower unit and remove the upper and lower gear lube drain screws to drain the oil.
3. Remove Lower Unit: Loosen and remove the bolts securing the lower unit (gear case) to the midsection.
4. Access Water Pump: With the lower unit removed, locate and unbolt the water pump housing.
5. Inspect and Remove: Carefully lift the housing. Note the rotational direction of the old impeller blades before removing the impeller and its keyway from the driveshaft.
6. Clean Surfaces: Thoroughly clean the inside of the pump housing and the base plate, removing any old gasket material or debris.
7. Install New Impeller: Lightly lubricate the new grommets and install the new plate and keyway. Slide the new impeller onto the driveshaft, turning it in the direction of engine rotation to seat the blades correctly.
8. Reassemble Pump: Reinstall the water pump housing, ensuring gaskets are properly aligned, and tighten bolts to the manufacturer's specified torque.
9. Reinstall Lower Unit: Guide the lower unit back into place, aligning the driveshaft, shift shaft, and water tube. Reinstall and tighten all bolts.
10. Refill Gear Lube: Using a pump, fill the lower unit with fresh marine gear lube from the bottom drain hole until it seeps out of the top hole. Reinstall both drain screws.
11. Test Operation: Reconnect the battery. Start the engine in a water source (using "earmuffs" or in the water) and confirm a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?

A: The best way is to check the part number on your original impeller. You can also use the extensive compatibility tables on this page to find your engine model, HP, and year. For Mercury owners, using our serial number guide can help pinpoint the exact model and original part numbers.

Q: How often should I replace the water pump impeller?

A: As a critical maintenance item, it is recommended to replace the impeller annually or every 100 hours of use, whichever comes first. This preventative measure helps avoid engine overheating and costly damage.

Q: What are the signs of a failing impeller?

A: The most common signs include a weak or non-existent water stream from the "tell-tale" outlet, an engine temperature alarm sounding, or the engine running hotter than usual. If you notice any of these symptoms, inspect your cooling system and impeller immediately.

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.