Water Pump Impeller for Yamaha 25–50 HP 2-Stroke Outboards – Replaces 6H4-44352-02-00, Sierra 18-3068
Water Pump Impeller for Yamaha 25–50 HP 2-Stroke Outboards – Replaces 6H4-44352-02-00, Sierra 18-3068 is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
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.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller for Yamaha 25–50 HP 2-Stroke Outboards – Replac...
Water Pump Impeller for Yamaha 25–50 HP 2-Stroke Outboards – Replaces 6H4-44352-02-00, Sierra 18-3068 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller is designed for selected Yamaha 25–50 HP 2-stroke outboards. It is a replacement for Yamaha OEM part number 6H4-44352-02-00 and Sierra reference 18-3068. Catalog applications document this impeller in Yamaha 30, 40, and 50 HP 2-stroke models, with exact fitment depending on the engine model, year, and serial-number range.
The impeller is used in the outboard water pump to circulate cooling water through the engine. Always compare the original impeller, engine model information, and OEM reference before ordering.
- Aftermarket replacement water pump impeller.
- For selected Yamaha 25–50 HP 2-stroke outboards.
- High-volume, long-vane impeller design associated with the 6H4-44352-02-00 application.
- Impeller supplied as a single component; water-pump gaskets, housing parts, and key are not included unless separately stated for the applicable offer.
Part Number Matrix
Use the following verified reference numbers to help identify the replacement. Part-number matching alone does not replace model, year, and serial-number verification.
| Brand | Reference | Reference Type |
|---|---|---|
| Yamaha | 6H4-44352-02-00 | OEM reference |
| Sierra | 18-3068 | Aftermarket reference |
Engine & Model Compatibility
The catalog evidence confirms the reference impeller in the following Yamaha 2-stroke applications. The ranges below are representative catalog occurrences, not a substitute for checking the complete model and serial-number information on your engine.
| Brand | Model Examples | Rated HP | Stroke | Documented Years | OEM Reference |
|---|---|---|---|---|---|
| Yamaha | 30ELH, 30ESH, 30LH, 30SH | 30 | 2-Stroke | 1987 | 6H4-44352-02-00 |
| Yamaha | 40ELN, 40ESN, 40LN, 40SN | 40 | 2-Stroke | 1984 | 6H4-44352-02-00 |
| Yamaha | 40ELK, 40ESK, 40ETLK, 40LK, 40SK | 40 | 2-Stroke | 1985 | 6H4-44352-02-00 |
| Yamaha | 40ELJ, 40ESJ, 40ETLJ, 40LJ, 40SJ | 40 | 2-Stroke | 1986 | 6H4-44352-02-00 |
| Yamaha | 50ETLK, 50ETLN, 50ETSK, 50ETSN | 50 | 2-Stroke | 1984–1985 | 6H4-44352-02-00 |
| Yamaha | 50ELJ, 50ELJ-JD, 50ESJ, 50ETLJ | 50 | 2-Stroke | 1986 | 6H4-44352-02-00 |
Do not assume compatibility with every Yamaha 25–50 HP engine or with Yamaha 4-stroke models. Confirm the complete model designation, year, serial-number range, and existing impeller dimensions before purchase.
Technical Specs
- Product Type
- Water pump impeller
- Application
- Selected Yamaha 25–50 HP 2-stroke outboards
- Impeller Style
- High-volume / long-vane design
- Outside Diameter
- 2.00 inches
- Inside Diameter
- 0.625 inches
- OEM Reference
- Yamaha 6H4-44352-02-00
- Aftermarket Reference
- Sierra 18-3068
- Installation
- Replacement installation in the water-pump housing
What’s in the Box
- 1 × Water pump impeller
Not included: Impeller key, water-pump gaskets, wear plate, housing, and other water-pump service parts unless specifically listed in the applicable offer.
Installation Notes
- Disconnect the battery and place the outboard in neutral. Follow the service manual for your exact engine.
- Remove the lower unit according to the manufacturer’s procedure.
- Remove the water-pump housing and carefully take out the old impeller and key.
- Inspect the housing, wear plate, drive key, water tube, and related gaskets for wear or damage.
- Install the correct key separately if the original key is serviceable or a replacement key has been obtained.
- Fit the new impeller onto the driveshaft and rotate it in the correct direction while seating the vanes in the housing.
- Reinstall the housing and any required gaskets, then reinstall the lower unit in accordance with the service manual.
- Run the engine only with an adequate water supply and confirm a strong tell-tale stream. Stop immediately if the engine overheats or water flow is abnormal.
Troubleshooting & FAQ
How do I confirm that this impeller fits my Yamaha engine?
Match the complete Yamaha model designation, horsepower, stroke type, year, and serial-number range with your service information. Also compare the existing impeller dimensions and the OEM reference 6H4-44352-02-00. The catalog evidence supports selected 2-stroke applications; it does not confirm every Yamaha 25–50 HP engine.
What are the signs of a failing water-pump impeller?
Common signs include a weak or intermittent tell-tale stream, overheating at low speed, an overheat alarm, or no visible cooling-water discharge. Shut down the engine if overheating is suspected and inspect the complete water-pump assembly.
Is the impeller key included?
No. This listing is for one impeller. The key is a separate service component and should be reused only if it is in good condition and matches the engine’s specification.
Do I need to replace the gaskets at the same time?
Inspect all water-pump gaskets, seals, the wear plate, and the housing during installation. Replace damaged, hardened, or worn parts as required by the service manual. These additional parts are not included with this impeller.
Is this an OEM or aftermarket part?
This is an aftermarket replacement part. Yamaha and Sierra references are provided for identification and compatibility purposes only. It is not manufactured by Yamaha or Sierra.
How often should a water-pump impeller be inspected?
Follow the maintenance schedule for your specific outboard. Inspect the impeller during scheduled water-pump service and replace it sooner if the engine has been operated in saltwater, sand, silt, or other abrasive conditions.
Safety & Important Information
- Verify the complete engine model, year, stroke type, and serial-number range before ordering.
- Do not operate the outboard without an adequate water supply.
- Inspect the complete water-pump assembly during installation; a new impeller cannot correct damage to the housing, wear plate, seals, or water tube.
- Professional installation is recommended if you are not familiar with outboard lower-unit service.
- This is an aftermarket replacement component, not an OEM Yamaha part.
About Sea Sierra
- Marine Replacement Parts — We provide replacement components for common marine maintenance and repair applications.
- Fitment-Focused Listings — Reference numbers and application details are presented to help customers verify compatibility before ordering.
- Practical Service Support — Review your engine information and existing component carefully when selecting replacement parts.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
