Water Pump Impeller Service Kit – Fits Mercury Marine & Tohatsu/Nissan 25-40 HP (Replaces 47-16154-1, 3R0-65021-0, 345-65021-0)
Water Pump Impeller Service Kit – Fits Mercury Marine & Tohatsu/Nissan 25-40 HP (Replaces 47-16154-1, 3R0-65021-0, 345-65021-0) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Impeller Service Kit – Fits Mercury Marine & Tohatsu...
Product Details
This Water Pump Impeller Service Kit is engineered for Mercury Marine 25-30 HP 4-Stroke Sea Pro/Lightning models (2005 and newer) and a wide range of Tohatsu/Nissan 25-40 HP 2-Stroke and 25-30 HP 4-Stroke outboard engines from 1996–2005. It provides a reliable solution for maintaining your engine's cooling system.
This kit serves as a direct replacement for Mercury part 47-16154-1, Tohatsu/Nissan parts 345-65021-0 and 3R0-65021-0, and interchanges with Sierra 18-8923, Mallory 9-45400, and CEF 500382.
- Engineered as a direct replacement for straightforward installation.
- Constructed from high-strength neoprene rubber with a durable nylon hub for longevity.
- Includes the essential impeller, key, and gaskets for a comprehensive service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury Marine | 47-16154-1 |
| Tohatsu/Nissan | 345-65021-0 / 345650210 / 345-65021-0M / 345650210M |
| Tohatsu/Nissan | 3R0-65021-0 / 3R0650210 / 3R0-65021-0M / 3R0650210M |
| Sierra | 18-8923 |
| Mallory | 9-45400 |
| CEF | 500382 |
Engine & Model Compatibility
Confirm your engine model/year in the tables below.
For Mercury Marine engines, this kit fits select 25-30 HP 4-Stroke Sea Pro and Lightning models from 2005 and newer. Always check your serial number range to confirm proper fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | Sea Pro | 25 EFI JET | 4-Stroke | 2005 and newer | 47-16154-1 | S/N 0N055505 & Up |
| Mercury | Lightning | 30 EFI JET | 4-Stroke | 2005 and newer | 47-16154-1 | S/N 0G575500 & Up |
Fits a range of Tohatsu and Nissan 25-40 HP 2-Stroke and 25-30 HP 4-Stroke outboard engines manufactured between approximately 1996 and 2005.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Tohatsu/Nissan | NS25C, M25C | 25 | 2-Stroke | 1996–2005 | 345-65021-0 |
| Tohatsu/Nissan | NS30A, M30A | 30 | 2-Stroke | 1996–2005 | 345-65021-0 |
| Tohatsu/Nissan | NS35C, M35C | 35 | 2-Stroke | 1996–2005 | 345-65021-0 |
| Tohatsu/Nissan | NS40C, M40C | 40 | 2-Stroke | 1996–2005 | 345-65021-0 |
| Tohatsu/Nissan | NSF25A, NSF25B, MFS25A, MFS25B, MFS25C | 25 | 4-Stroke | 1996–2005 | 345-65021-0 |
| Tohatsu/Nissan | NSF30A, NSF30B, MFS30A, MFS30B, MFS30C | 30 | 4-Stroke | 1996–2005 | 345-65021-0 |
Technical Specs
- Product Type
- Water Pump Impeller Service Kit
- Installation
- Direct replacement
- Material
- Neoprene rubber with nylon hub
- Number of Blades
- 6
- Impeller Height
- 20.3 mm (0.80 inch)
- Overall Diameter
- 44.1 mm (1.74 inch)
- Hub Shaft Diameter
- 17.1 mm (0.67 inch)
What’s in the Box
- 1 x Water Pump Impeller (345-65021-0/47-16154-1/161541)
- 1 x Impeller Key (332-65022-0)
- 2 x Water Pump Housing Gaskets
- 1 x Installation Instructions
Installation Notes
- Disconnect the battery and shut off the fuel supply for safety.
- Remove the lower unit (gearcase) by unfastening its mounting bolts.
- Unbolt and carefully lift off the water pump housing cover.
- Note the rotational direction of the old impeller's blades before removal.
- Remove the old impeller, impeller key, and any existing gaskets.
- Thoroughly clean the housing interior and wear plate, inspecting for grooves or damage.
- Install the new gasket and impeller key onto the driveshaft.
- Slide the new impeller onto the driveshaft, turning the shaft clockwise to correctly seat the blades inside the housing.
- Re-install the water pump housing and tighten its bolts to the manufacturer's specified torque.
- Carefully re-attach the lower unit, ensuring the water tube and shift shaft are correctly aligned.
- Once assembled, test the engine using a water supply, and verify a strong, steady stream from the tell-tale port.
Troubleshooting & FAQ
How do I know if this impeller kit fits my engine?
The most reliable method is to match your engine's model, year, and serial number against our compatibility tables. Additionally, you can cross-reference the OEM part number found in your service manual with the numbers listed in our Part Number Matrix.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or intermittent water stream from the engine's tell-tale outlet, overheating alarms, or a noticeable drop in engine performance. A physical inspection will often reveal blades that are cracked, brittle, melted, or missing chunks.
How often should I replace the impeller?
As a preventative maintenance measure, we recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of use. Replacement frequency should be increased for engines operated in saltwater or sandy/silty conditions.
Is this part the same as the original OEM version?
This is an aftermarket part designed to meet or exceed OEM specifications for fit, material, and performance. It is made from high-quality neoprene and produced in an ISO 9002 certified facility, offering a reliable and cost-effective alternative to OEM parts.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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