Water Pump Impeller Service Kit – Fits Mercury Marine & Tohatsu/Nissan 25-40 HP (Replaces 47-16154-1, 3R0-65021-0, 345-65021-0)

Water Pump Impeller Service Kit – Fits Mercury Marine & Tohatsu/Nissan 25-40 HP

This water pump impeller service kit is designed for a range of Mercury Marine and Tohatsu/Nissan outboard engines. It fits specific Mercury Marine 25-30 HP 4-Stroke Sea Pro/Lightning models from 2005 and newer, as well as Tohatsu/Nissan 25-40 HP 2-Stroke and 25-30 HP 4-Stroke models from 1996 through 2005.

This kit serves as a direct replacement for Mercury part number 47-16154-1 and Tohatsu/Nissan part numbers 3R0-65021-0 and 345-65021-0, ensuring precise compatibility and performance.

• Complete Service Kit: Includes a high-quality neoprene impeller, impeller key, and housing gaskets for a full replacement.
• Durable Construction: The impeller is made from robust neoprene rubber with a nylon hub for reliable, long-lasting service.
• Direct Installation: Engineered to match OEM specifications for a straightforward installation without modifications.

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.

Mercury Marine

Tohatsu/Nissan

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 345-65021-0 / 47-16154-1 / 161541)
• 1 x Impeller Key (Replaces 332-65022-0)
• 2 x Water Pump Housing Gaskets
• 1 x Installation Instructions

Installation Guide

Always follow your engine's service manual for detailed instructions. The general steps for replacing a water pump impeller are as follows:

1. Safety First: Disconnect the battery and the spark plug leads to prevent accidental starting.
2. Access the Lower Unit: Drain the gearcase lubricant. Unbolt and carefully remove the lower unit (gearcase) from the outboard's driveshaft housing.
3. Open the Water Pump: Locate and remove the bolts securing the water pump housing cover.
4. Remove Old Impeller: Note the rotational direction of the old impeller vanes as you remove it. Take out the old impeller, gaskets, and impeller key.
5. Clean and Inspect: Thoroughly clean the inside of the housing and inspect it for scoring, cracks, or wear. Replace the housing if damage is found.
6. Install New Components: Install the new housing gaskets. Slide the new impeller key into place on the driveshaft.
7. Install New Impeller: Lubricate the new impeller with a small amount of soap and water. Slide it onto the driveshaft while turning the shaft in its normal rotational direction to seat the vanes correctly.
8. Reassemble: Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
9. Reattach Lower Unit: Guide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube align correctly. Secure it with the mounting bolts.
10. Final Checks: Refill the gearcase with fresh lubricant. Reconnect the spark plug leads and battery.
11. Test Operation: Start the engine in a suitable water source and immediately check for a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my specific engine?

A: The best way is to compare the part number on your existing impeller with the numbers listed in our Part Number Cross-Reference table. You can also use our Compatible Engine Models table and the linked serial number guides to verify your model and year range before purchasing.

Q: What are the signs of a worn or failed water pump impeller?

A: Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and a noticeable drop in engine performance. Visible signs on the impeller itself include cracked, brittle, or missing vanes.

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

A: For preventative maintenance, most marine mechanics and engine manufacturers recommend replacing the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can vary based on usage conditions (e.g., saltwater vs. freshwater).

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.