Impeller – Fits Yamaha 2 HP 2-Stroke Outboard Motors (Replaces 646-44352-01-00)

Water Pump Impeller for Yamaha 2 HP 2-Stroke Outboards (1987-2002)

This water pump impeller is a direct replacement part designed for Yamaha 2 HP 2-stroke outboard motors manufactured between 1987 and 2002. It is engineered to meet or exceed original equipment specifications, ensuring reliable cooling performance.

This component serves as a direct replacement for several aftermarket parts, including Sierra 18-3074, Mallory 9-45605, NGK 89880, and Aqua Power 2171.

• Installation Type: Direct fit to the drive shaft with a key-slotted design.
• Durable Construction: Made from high-quality neoprene rubber with a brass insert for corrosion resistance and longevity.
• Efficient Design: Features a 6-blade design for optimal water flow and cooling efficiency.

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 Yamaha owners, here’s a guide to help you identify your engine’s serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Impeller (646-44352-01-00)

Explosion Diagram

Installation Guide

Follow these steps to replace your water pump impeller. Always consult your owner's manual for detailed instructions and safety warnings specific to your engine model.

1. Disconnect the battery and remove the engine cover.
2. Locate and unbolt the lower unit (gearcase) from the outboard's upper casing.
3. Carefully separate the lower unit. Be mindful of the shift linkage and disconnect it if necessary.
4. Unscrew the bolts on the water pump housing and lift the housing off the driveshaft.
5. Note the rotational direction of the old impeller's blades before removing it, along with the drive key.
6. Clean any debris or corrosion from the wear plate and inside the pump housing.
7. Install the new drive key and slide the new impeller onto the driveshaft.
8. Rotate the driveshaft clockwise while pushing down on the impeller to correctly seat the blades inside the housing.
9. Reinstall the water pump housing, ensuring gaskets are aligned, and tighten bolts to the manufacturer's specified torque.
10. Reattach the lower unit, reconnecting the shift linkage, and secure it to the engine.
11. Attach a water supply (flushing muffs) to the lower unit, start the engine, and confirm a steady stream of water is exiting the tell-tale port.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: This impeller is designed for Yamaha 2 HP 2-Stroke outboards from 1987–2002. Please review the 'Compatible Engine Models' table and cross-reference your engine's model and year. Verifying the OEM part number, 646-44352-01-00, against your service manual is the best way to ensure an exact match.

Q: How often should a water pump impeller be replaced?
A: For optimal engine cooling, we recommend inspecting the impeller annually and replacing it every 1-2 years or 100-200 hours of use, whichever comes first. Proactive replacement prevents overheating and costly engine damage.

Q: What are the signs of a failing impeller?
A: A weak or non-existent water stream from the "tell-tale" port is the most common indicator. Other signs include the engine running hotter than normal or a high-temperature alarm sounding. If you notice any of these symptoms, inspect the impeller immediately.

Q: Is this part the same as a Sierra 18-3074?
A: Yes, this impeller is a direct aftermarket replacement for Sierra part number 18-3074, as well as Mallory 9-45605 and Aqua Power 2171.

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.