Water Pump Impeller – Fits Tohatsu/Nissan 6, 8 & 9.8 HP Outboards (Replaces 3B2-65021-1, CEF 500344)
Water Pump Impeller – Fits Tohatsu/Nissan 6, 8 & 9.8 HP Outboards (Replaces 3B2-65021-1, CEF 500344) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Water Pump Impeller – Fits Tohatsu/Nissan 6, 8 & 9.8 HP Outboar...
Water Pump Impeller – Fits Tohatsu/Nissan 6, 8 & 9.8 HP Outboards (Replaces 3B2-65021-1, CEF 500344) is backordered and will ship as soon as it is back in stock.
Product Details
This high-quality water pump impeller is designed for selected Tohatsu and Nissan 6, 8, and 9.8 HP outboard engines. It replaces the original Tohatsu/Nissan reference 3B2-65021-1 and is matched to the CEF 500344 impeller specification for reliable water circulation through the outboard cooling system.
The impeller is installed in the lower-unit water pump assembly. Regular inspection and timely replacement help maintain cooling-water flow and reduce the risk of overheating caused by worn, cracked, or damaged impeller blades.
- Aftermarket replacement water pump impeller for selected small outboards.
- Applicable to the 6, 8, and 9.8 HP impeller application shown in the compatibility information below.
- Designed for the lower-unit water pump assembly.
- Verify the engine model, stroke, year, serial number, and original impeller dimensions before ordering.
Part Number Matrix
These are manufacturer and aftermarket reference numbers associated with this impeller application. They are provided for identification and cross-reference purposes only.
| Brand | Part Number |
|---|---|
| Tohatsu / Nissan | 3B2-65021-1 |
| CEF | 500344 |
| Sierra | 18-8920 |
| Parsun | PAF8-04000200 |
Engine & Model Compatibility
Fitment must be confirmed against the complete engine identification information. Horsepower alone is not sufficient because water-pump components can vary by model family, stroke, year, and serial-number range.
| Brand | Model or Application | Rated HP | Stroke | OEM Reference | Notes |
|---|---|---|---|---|---|
| Tohatsu | Selected 6, 8, and 9.8 HP models | 6 / 8 / 9.8 | Confirm for exact engine | 3B2-65021-1 | Match the original impeller and engine identification before purchase. |
| Tohatsu | MFS8 / MFS9.8 applications | 8 / 9.8 | 4-Stroke | 3B2-65021-1 | Confirm the precise model and serial-number range. |
| Nissan | Selected engines sharing the 3B2-65021-1 application | 6 / 8 / 9.8 | Confirm for exact engine | 3B2-65021-1 | Use the original part number and dimensions for final verification. |
| Parsun | Selected F6, F8, and F9.8 applications | 6 / 8 / 9.8 | Confirm for exact engine | PAF8-04000200 | Aftermarket cross-reference; verify against the engine and old impeller. |
Technical Specs
- Product Type
- Water pump impeller
- Installation
- Replaceable component in the lower-unit water pump assembly
- Material
- Neoprene rubber with a molded hub
- Outer Diameter
- Approximately 40 mm
- Hub Diameter
- Approximately 18 mm
- Inner Shaft Opening
- Approximately 12.1 mm; compare with the original impeller before installation
- Reference Specification
- CEF 500344 / Tohatsu 3B2-65021-1 application
- Warranty
- 1 year, subject to the applicable supplier terms
What’s in the Box
- 1 x Water pump impeller
A drive key, gasket, housing, wear plate, and other water-pump components are not included unless specifically shown or stated in the order details.
Installation Notes
- Disconnect the battery or otherwise disable the engine to prevent accidental starting.
- Place a drain pan under the lower unit and remove the gear-oil drain and fill screws if lower-unit removal requires draining the gearcase.
- Remove the fasteners securing the lower unit to the mid-section and carefully lower the gearcase.
- Remove the water-pump housing cover to expose the impeller.
- Remove the old impeller and drive key if fitted. Note the key position and the direction in which the original blades were folded.
- Clean debris and corrosion from the impeller housing and inspect the housing and wear plate for grooves, distortion, or other damage.
- Install the original or correctly specified drive key, then fit the new impeller over the shaft.
- Use a suitable water-pump assembly lubricant during installation. Turn the driveshaft in the correct direction for the engine while seating the impeller blades.
- Reinstall the water-pump housing and tighten its fasteners to the engine manufacturer’s specifications.
- Reattach the lower unit, ensuring that the driveshaft, shift shaft, and water tube are properly aligned.
- Refill the gearcase with the specified marine gear oil if it was drained, following the engine manufacturer’s procedure.
- Run the engine only with an adequate water supply and confirm a strong, steady tell-tale stream before normal operation.
Troubleshooting & FAQ
How do I confirm this impeller fits my exact engine?
Match the complete engine model, year, serial number, stroke, and original impeller reference. Also compare the old impeller’s outer diameter, hub, shaft opening, and drive-key arrangement. The 3B2-65021-1 application is associated with selected Tohatsu/Nissan 6, 8, and 9.8 HP engines, but not every engine in those horsepower classes uses the same impeller.
What are the signs of a failing water-pump impeller?
Common signs include a weak or missing tell-tale stream, an overheating warning, rising engine temperature, damaged or missing blades, or a rubber impeller that has become brittle or deformed.
How often should I replace the impeller?
Inspect the impeller regularly and replace it according to the engine manufacturer’s maintenance schedule. Frequent use in saltwater, sand, silt, or polluted water can shorten service life and may require more frequent inspection.
Is the drive key included?
No drive key is included with this impeller listing unless the order details specifically state otherwise. Reuse the correct serviceable key or obtain the properly specified replacement key separately.
Why does the engine still overheat after replacing the impeller?
Check the blade orientation, drive key, water-pump housing, wear plate, water-intake passages, water tube, thermostat, and cooling passages. A damaged housing or blocked cooling system can prevent proper water circulation even when the impeller is new.
Is this an OEM part?
This is an aftermarket replacement impeller. The listed manufacturer and aftermarket numbers are reference numbers used to help identify the intended application; they do not indicate that this product is manufactured by Tohatsu, Nissan, CEF, Sierra, or Parsun.
How fast is shipping and what does it cost?
Typical transit is 5–15 days. Standard shipping is free to most regions, with expedited options available at checkout where applicable.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use, subject to the applicable supplier terms. Returns are accepted within the standard return window for unused items in their original condition. Contact support for current policy details and return instructions.
Safety & Important Information
- Confirm the exact engine model, year, serial number, stroke, and original impeller dimensions before ordering.
- Do not rely on horsepower alone to determine fitment.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended if you are unfamiliar with lower-unit or water-pump service.
- Never run an outboard without an adequate cooling-water supply.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for dependable service in real-world conditions.
- Fast Global Fulfillment — Free standard delivery is available to most regions, with typical transit of 5–15 days.
- Manufacturer-Direct Value — Fair pricing with attention to material quality and production consistency.
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