Water Pump Impeller Kit – Fits Mercury Marine 25-30 HP & Tohatsu/Nissan 25-40 HP (Replaces 853792A07, 361873220)

Water Pump Impeller Kit – Fits Mercury Marine 25-30 HP & Tohatsu/Nissan 25-40 HP

This comprehensive water pump repair kit is designed for a direct fit on Mercury Marine 25-30 HP 4-Stroke EFI engines (2002 and up). It also provides broad coverage for various Tohatsu and Nissan 25-40 HP 2-Stroke engines (1996-2005) and 25-30 HP 4-Stroke engines (2002-2017), restoring cooling system performance and reliability.

This kit serves as a direct replacement for Mercury part numbers 853792A07, 853792A1, and 853792T01, as well as Tohatsu/Nissan parts 361-87322-0, 361873220M, and 361873220.

• Installation Type: Direct OEM-style replacement.
• Complete Assembly: Includes a new impeller, gaskets, wear plate, insert cup, and hardware.
• Quality Construction: Made with a durable neoprene rubber impeller and marine-grade stainless steel components.

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 (345-65021-0/47-16154-1/161541)
• 1 x Impeller Key (28-161582/348-65018)
• 1 x Gasket (278-161602/348-65029-1)
• 1 x Gasket (27-161582/348-65018-0)
• 1 x Insert Cup (161572/348-65011-0)
• 1 x Wear Plate (161592/348-65025-0)
• 4 x Bolts & Washers (910103-565)

Installation Guide

1. Safety First: Disconnect the battery and disable the ignition system before beginning.
2. Access the Pump: Remove the lower unit (gearcase) from the outboard motor to access the water pump assembly.
3. Disassemble Housing: Unbolt and remove the water pump housing, taking note of how the components are assembled.
4. Remove Old Parts: Take out the old impeller, gaskets, wear plate, and insert cup. Clean all mating surfaces thoroughly.
5. Install New Components: Install the new gasket, wear plate, and insert cup into the housing.
6. Install Impeller: Slide the new impeller onto the driveshaft. Turn the shaft clockwise while pushing down to correctly orient the impeller vanes.
7. Reassemble Housing: Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
8. Reinstall Lower Unit: Reattach the lower unit to the engine, ensuring the driveshaft and shift shaft align correctly.
9. Test Operation: Reconnect the battery. Start the engine in a water supply (using flushing muffs or in the water) and confirm that water is exiting the tell-tale port.

Troubleshooting & FAQ

How do I confirm this fits my engine?
The most reliable method is to match your engine's model and serial number against our compatibility tables. For Mercury engines, year ranges are often given by serial number breaks (e.g., "0R106999 & Up"). Cross-reference the OEM part number stamped on your old parts with those listed in our cross-reference table.

What are the signs of a failing water pump impeller?
Common signs include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, or visible cracks, stiffness, or missing blades on the old impeller upon inspection.

How often should I replace the water pump impeller?
As a critical preventative maintenance item, most manufacturers recommend replacing the impeller 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, silty, or saltwater conditions.

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.