Description
Water Pump ImpellerFits Tohatsu & Nissan 9.9HP-20HP (Replaces 334-65021-0)
This water pump impeller is designed for a wide range of Tohatsu and Nissan outboard motors. It fits Tohatsu 2-stroke (M9.9, M12, M15, M18) and 4-stroke (MFS9.9, MFS15, MFS18, MFS20) models, as well as Nissan 2-stroke (NS9.9, NS15, NS18) and 4-stroke (NSF9.9, NSF15, NSF18, NSF20) models.
It serves as a direct replacement for multiple OEM part numbers, including Tohatsu/Nissan 334-65021-0, Mercury 47-803748, Honda 19210-935-003, and Evinrude 5040046.
- Installation Method: Direct Replacement
- Fuel Compatibility: Gasoline
- Package Contents: Includes one water pump impeller
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Tohatsu / Nissan | 334-65021-0 / 334650210 / 334650210M |
| Mercury | 47-803748 / 8M0214944 |
| Honda | 19210-935-003 |
| Evinrude | 5040046 |
| Sierra | 18-8921 |
Compatible Engine Models
Confirm your engine model/year in the table below.
For Mercury owners, heres a guide to help you identify your engines serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
For Johnson/Evinrude owners, heres a guide to help you identify your engines serial/model: Johnson Serial Number Guide.
| Brand | Model | Rated HP | Stroke | OEM Part No. |
|---|---|---|---|---|
| Tohatsu | M9.9 | 9.9 | 2-Stroke | 334-65021-0 |
| Tohatsu | M12 | 12 | 2-Stroke | 334-65021-0 |
| Tohatsu | M15 | 15 | 2-Stroke | 334-65021-0 |
| Tohatsu | M18 | 18 | 2-Stroke | 334-65021-0 |
| Tohatsu | MFS9.9 | 9.9 | 4-Stroke | 334-65021-0 |
| Tohatsu | MFS15 | 15 | 4-Stroke | 334-65021-0 |
| Tohatsu | MFS18 | 18 | 4-Stroke | 334-65021-0 |
| Tohatsu | MFS20 | 20 | 4-Stroke | 334-65021-0 |
| Nissan | NS9.9 | 9.9 | 2-Stroke | 334-65021-0 |
| Nissan | NS15 | 15 | 2-Stroke | 334-65021-0 |
| Nissan | NS18 | 18 | 2-Stroke | 334-65021-0 |
| Nissan | NSF9.9 | 9.9 | 4-Stroke | 334-65021-0 |
| Nissan | NSF15 | 15 | 4-Stroke | 334-65021-0 |
| Nissan | NSF18 | 18 | 4-Stroke | 334-65021-0 |
| Nissan | NSF20 | 20 | 4-Stroke | 334-65021-0 |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Water Pump Impeller |
| Installation | Direct Replacement |
| Fuel Type | Gasoline |
| Housing Material | Plastic Hub |
| Dimensions | Overall Diameter: 41.11mm, Height: 23.51mm, Internal Shaft Insert Diameter: 13.88mm |
| Weight | 12g (0.42oz) |
| Number of Blades | 8 |
| Other Technical Attributes | For saltwater use |
Package Contents
- 1 x Water Pump Impeller (334-65021-0)
Installation Guide
- Safety First: Disconnect the engine’s battery and remove the safety lanyard from the kill switch.
- Access the Lower Unit: Place the outboard in a secure position. Locate and unbolt the lower unit (gearcase) from the upper engine leg.
- Remove Lower Unit: Carefully separate the lower unit from the driveshaft housing. You may need to disconnect a speedometer tube or shift linkage.
- Open Water Pump Housing: Locate the water pump assembly on top of the lower unit. Unscrew the bolts to remove the pump cover.
- Remove Old Impeller: Note the rotational direction of the old impeller’s blades before sliding it off the driveshaft.
- Inspect and Clean: Clean the inside of the pump housing and the wear plate. Inspect them for grooves, warping, or damage and replace if necessary.
- Install New Impeller: Lightly lubricate the new impeller and the inside of the housing. Slide the new impeller onto the driveshaft while turning the shaft clockwise to correctly bend the blades.
- Reassemble: Reinstall the water pump housing and torque the bolts to the manufacturer’s specification.
- Reattach Lower Unit: Guide the lower unit back into place, ensuring the driveshaft, water tube, and shift shaft align correctly. Bolt it securely.
- Test Operation: Reconnect the battery. Start the engine in a water test tank or with a hose attachment to confirm a strong and steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this impeller fits my Tohatsu or Nissan engine?
This impeller fits a range of 9.9HP to 20HP Tohatsu and Nissan outboards. Please check the ‘Compatible Engine Models’ table on this page to match your specific model. Verifying the OEM part number (334-65021-0) against your engine’s service manual is the most reliable method.
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, and a noticeable decrease in engine performance. A worn or damaged impeller cannot move enough water to cool the engine effectively.
How often should I replace my water pump impeller?
For optimal reliability, it is recommended to inspect the impeller annually and replace it every 1-2 years, or after every 100-200 hours of use, depending on operating conditions. More frequent replacement may be necessary if you operate in sandy, silty, or saltwater environments.
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 shippingtypically 515 days worldwideand 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 existeven if your model is listeddo 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 515 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.
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