334-65021-0 Water Pump Impeller for Tohatsu Nissan M9.9 M12 M15 M18 MFS9.9 MFS15 MFS18 MFS20 NS9.9 NS15 NS18 NSF9.9 NSF15 NSF18 NSF20 | JLM Marine

Water Pump Impeller 334-65021-0 – Fits Tohatsu Nissan 2-Stroke & 4-Stroke 9.9–20 HP Outboard Motors

This replacement water pump impeller is engineered for Tohatsu 2-stroke outboard motors (M9.9, M12, M15, M18), Tohatsu 4-stroke outboard motors (MFS9.9, MFS15, MFS18, MFS20), Nissan 2-stroke outboard motors (NS9.9, NS15, NS18), and Nissan 4-stroke outboard motors (NSF9.9, NSF15, NSF18, NSF20). As the critical component of your water pump, it ensures a continuous supply of the correct amount of coolant to your engine for reliable performance.

This impeller directly replaces OEM part number 334-65021-0 and is cross-referenced with Sierra 18-8921 and CEF 500383. It is made of high-performance neoprene rubber, scientifically engineered to resist marine and chemical corrosion for extreme durability and long-lasting service.

• Includes impeller with key/pin for complete installation
• 8-blade design for optimal water flow and cooling efficiency
• Carrying a spare impeller on your craft is advisable for peace of mind

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.

Technical Specifications

Package Contents

• 1 × Outboard Rubber Impeller with Key / Pin

Installation Guide

1. Disconnect the fuel line and remove the engine cowling to access the lower unit. Ensure the engine is completely cool before beginning work.
2. Remove the water pump housing by unscrewing the bolts securing it to the lower unit. Keep all fasteners organized for reassembly.
3. Extract the old impeller carefully from the pump housing, noting the direction of the blades. Inspect the housing for wear or damage.
4. Clean the pump housing thoroughly, removing any debris, old gasket material, or corrosion that may affect the seal.
5. Lubricate the new impeller with water pump grease or glycerin to ease installation and prevent blade damage during the first startup.
6. Insert the key/pin into the shaft slot according to your engine's configuration. Ensure it is seated properly before proceeding.
7. Install the new impeller onto the shaft, rotating the blades in the correct direction as noted during removal. Press it firmly into place.
8. Reinstall the water pump housing, ensuring the impeller blades are not folded or damaged. Align the housing carefully before tightening bolts.
9. Torque all fasteners to manufacturer specifications in a star pattern to ensure even pressure and prevent leaks.
10. Reconnect the fuel line and replace the engine cowling securely.
11. Test the cooling system by running the engine in water (using a flush attachment or in-water test). Verify consistent water flow from the telltale outlet.
12. Inspect for leaks around the pump housing and ensure the engine reaches normal operating temperature without overheating.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my Tohatsu or Nissan outboard?
A: Cross-reference your engine model with the compatibility table above. Verify that your original impeller matches OEM part number 334-65021-0, or check the technical specifications (41.20 mm external diameter, 14.00 mm shaft diameter, 8 blades) against your current impeller.

Q: How often should I replace my water pump impeller?
A: Most manufacturers recommend replacing the impeller annually or every 200–300 hours of operation, whichever comes first. If you frequently operate in sandy or debris-laden water, inspect it more often. Carrying a spare impeller onboard is advisable for emergency replacements.

Q: What are the signs that my impeller is failing?
A: Common symptoms include reduced or no water flow from the telltale outlet, engine overheating, steam from the exhaust, or visible damage to impeller blades (cracking, missing pieces, or bent vanes). Replace the impeller immediately if any of these occur.

Q: Can I use this impeller on both 2-stroke and 4-stroke Tohatsu/Nissan engines?
A: Yes, this impeller is compatible with both 2-stroke (M9.9, M12, M15, M18, NS9.9, NS15, NS18) and 4-stroke (MFS9.9, MFS15, MFS18, MFS20, NSF9.9, NSF15, NSF18, NSF20) models as listed in the compatibility table.

Q: What is the difference between this aftermarket impeller and the OEM version?
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.