Water Pump Impeller – Fits Tohatsu/Nissan/Mercury 40-90HP 2-Stroke (Replaces 3B7-65021-2)

Water Pump Impeller – Fits Tohatsu/Nissan/Mercury 40-90HP 2-Stroke (Replaces 3B7-65021-2)

This aftermarket water pump impeller fits a range of Tohatsu, Nissan, and Mercury outboard motors. It is designed for select 60-140HP 2-Stroke and 8-9.8HP 4-Stroke Tohatsu/Nissan models, as well as specific 8-9.9HP 4-Stroke Mercury outboards. It is also compatible with certain Parsun F6 and F8 models.

This component is a direct replacement for multiple OEM and aftermarket part numbers, including Tohatsu 3B7-65021-2, 3C7-65021-1, 3B2-65021-1, Mercury 8M0214945, and Sierra 18-8924, ensuring a precise fit for scheduled maintenance or repairs.

• Engine Location: Lower Unit/Gearcase
• Technical Design: Features a 6-blade design with a keyed hub for a secure fit on the driveshaft.
• Package Contents: Includes one water pump impeller.

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 Tohatsu/Nissan and Parsun models, confirm your engine model/year in the tables below.

Tohatsu/Nissan

Mercury

Parsun

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 3B7-65021-2 / 3C7-65021-1 / 3B2-65021-1)

Installation Guide

1. Disconnect the battery and shift the outboard into the neutral position.
2. Place a drain pan under the lower unit and remove the gearcase oil drain screw to empty the oil.
3. Unbolt and remove the bolts securing the lower unit (gearcase) to the engine's upper casing.
4. Carefully lower and detach the unit, being mindful of the driveshaft and shift shaft linkage.
5. Locate and unbolt the water pump housing cover to expose the impeller.
6. Observe the rotational direction of the existing impeller's blades before removing it. Pull the old impeller straight off the driveshaft, removing the key as well.
7. Clean the impeller housing and wear plate, inspecting them for grooves, warping, or damage. Replace if necessary.
8. Install the new key into the driveshaft keyway and slide the new impeller onto the shaft.
9. Apply a light coat of marine-safe lubricant to the inside of the housing and to the impeller blades.
10. Reinstall the water pump housing, ensuring a proper seal. Tighten the bolts to the manufacturer's recommended torque specifications.
11. Carefully guide the lower unit back into place, aligning the driveshaft, shift shaft, and water tube. Secure it with the mounting bolts.
12. Refill the gearcase with the correct type and amount of marine gear oil and test the engine with a reliable water source (like "earmuffs" or in a test tank).

Troubleshooting & FAQ

How do I confirm this impeller fits my engine?
Cross-reference your engine's model, year, and horsepower with the "Compatible Engine Models" table. For best results, also compare your old part number to the list under "Part Number Cross-Reference." Verifying dimensions and serial number ranges is the most reliable way to ensure a correct fit.

What are the signs of a failing water pump impeller?
The most common symptoms are engine overheating at idle or low speeds, a weak or intermittent water stream from the "telltale" indicator outlet, or an alarm from your engine's temperature sensor.

How often should I replace the impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation, depending on usage and water conditions (saltwater vs. freshwater).

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.