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 Outboards

This replacement water pump impeller is engineered for Tohatsu 2-stroke outboards (M9.9, M12, M15, M18) and 4-stroke models (MFS9.9, MFS15, MFS18, MFS20), as well as Nissan 2-stroke motors (NS9.9, NS15, NS18) and 4-stroke motors (NSF9.9, NSF15, NSF18, NSF20). It ensures a continuous supply of coolant to your engine, safeguarding against overheating and maintaining optimal performance.

Direct Replacement for: Nissan Tohatsu OEM 334-65021-0, Sierra 18-8921, CEF 500383. This impeller is the critical component of your water pump system and is made of marine-grade, chemical-corrosion-resistant neoprene rubber for durability and long-lasting performance.

• Constructed from high-strength neoprene rubber resistant to marine and chemical corrosion
• Features 8 blades for efficient water flow and cooling
• Carrying a spare impeller on board is highly advisable for emergency repairs

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 Impeller (Replacement for Nissan Tohatsu OEM 334-65021-0, 9.9/15/18/20 HP)

Installation Guide

1. Disconnect the fuel line and remove the lower unit from the outboard motor according to your engine's service manual.
2. Remove the water pump housing cover by unscrewing the retaining bolts. Keep all hardware organized for reassembly.
3. Carefully extract the old impeller from the pump housing. Inspect the housing and pump plate for wear, corrosion, or debris.
4. Clean the pump housing thoroughly and apply a thin coat of water-resistant marine grease to the interior walls and the new impeller blades.
5. Insert the new impeller into the housing, ensuring the blades are oriented in the correct rotation direction (typically counter-clockwise when viewed from above).
6. Align the impeller key with the drive shaft slot and gently press it into place. Do not force; blades should flex naturally.
7. Reinstall the pump plate and housing cover, torquing bolts to manufacturer specifications in a cross-pattern to ensure even sealing.
8. Reattach the lower unit to the engine, reconnect the fuel line, and refill the lower unit gear oil if drained during service.
9. Test the cooling system by running the engine with a flush adapter or in a test tank. Confirm steady water discharge from the tell-tale indicator.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my Tohatsu or Nissan outboard?
A: Verify your engine model matches one listed in the Compatible Engine Models table (M9.9–M18, MFS9.9–MFS20, NS9.9–NS18, or NSF9.9–NSF20). Cross-check the OEM part number 334-65021-0 in your service manual or on your original impeller.

Q: How often should I replace my water pump impeller?
A: Replace the impeller annually or every 100–200 operating hours, whichever comes first. Inspect it more frequently if you operate in sandy, silty, or debris-laden water.

Q: What are the signs of a failing impeller?
A: Common symptoms include reduced or no water flow from the tell-tale indicator, engine overheating, steam from the motor, or weak discharge pressure. Replace immediately if you notice any of these issues.

Q: Can I install this impeller myself, or do I need a mechanic?
A: Experienced DIYers with basic tools and a service manual can perform this replacement. However, professional installation is recommended if you are unfamiliar with lower-unit disassembly or water pump service.

Q: How does this aftermarket impeller compare to the OEM Tohatsu/Nissan part?
A: This impeller is manufactured to OEM specifications using high-grade neoprene rubber in an ISO9002-certified facility. It offers comparable performance and durability at a more competitive price point.

Q: Is this an OEM or aftermarket part?
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.