Water Pump Impeller Service Kit for Mercury Marine and Tohatsu/Nissan 25–40 HP Outboards – Replaces 47-16154-1, 3R0-65021-0 and 345-65021-0
Water Pump Impeller Service Kit for Mercury Marine and Tohatsu/Nissan 25–40 HP Outboards – Replaces 47-16154-1, 3R0-65021-0 and 345-65021-0 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Impeller Service Kit for Mercury Marine and Tohatsu/Niss...
Water Pump Impeller Service Kit for Mercury Marine and Tohatsu/Nissan 25–40 HP Outboards – Replaces 47-16154-1, 3R0-65021-0 and 345-65021-0 is backordered and will ship as soon as it is back in stock.
Product Details
This water pump impeller service kit is designed for select Mercury Marine 25–30 HP 4-Stroke Sea Pro and Lightning outboard models, as well as a range of Tohatsu and Nissan 25–40 HP 2-Stroke and 25–30 HP 4-Stroke outboard engines. It provides the primary replacement components needed to service the water pump and maintain proper engine cooling.
This aftermarket kit is listed as a replacement for Mercury part 47-16154-1 and Tohatsu/Nissan parts 345-65021-0 and 3R0-65021-0. It also cross-references Sierra 18-8923, Mallory 9-45400 and CEF 500382. Confirm the part number, model, year and serial-number range before ordering.
- Replacement water pump impeller service kit for selected Mercury, Tohatsu and Nissan outboards.
- Neoprene rubber impeller with a durable nylon hub.
- Includes the impeller, key and water pump housing gaskets required for the listed service application.
Part Number Matrix
Use the following references to compare the listed OEM and aftermarket numbers with the number on your original component or service manual.
| 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
Fitment depends on the complete engine configuration. Match the engine brand, model, year, stroke, horsepower and serial-number range against the information below and verify the replacement number in your service manual before installation.
For Mercury Marine applications, the listed fitment includes select 25–30 HP 4-Stroke Sea Pro and Lightning models from 2005 and newer.
| 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 and up |
| Mercury | Lightning | 30 EFI JET | 4-Stroke | 2005 and newer | 47-16154-1 | S/N 0G575500 and up |
The listed Tohatsu and Nissan applications include selected 25–40 HP 2-Stroke and 25–30 HP 4-Stroke outboard engines manufactured approximately between 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 for the listed applications
- Material
- Neoprene rubber impeller 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, cross-referenced to 345-65021-0, 47-16154-1 and 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 or gearcase according to the engine manufacturer’s service procedure.
- Unbolt and carefully remove the water pump housing cover.
- Note the rotational direction of the old impeller blades before removal.
- Remove the old impeller, impeller key and used gaskets.
- Clean the housing interior and wear plate, and inspect them for grooves, cracks or other damage.
- Install the new gasket and impeller key onto the driveshaft.
- Slide the new impeller onto the driveshaft while turning the shaft in the correct direction so the blades seat properly in the housing.
- Reinstall the water pump housing and tighten the bolts to the manufacturer’s specified torque.
- Reattach the lower unit, ensuring that the water tube and shift shaft are correctly aligned.
- Test the engine with an appropriate water supply and verify a strong, steady stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this impeller kit fits my engine?
Match the engine brand, model, year, horsepower, stroke and serial-number range against the compatibility information. Also compare the OEM or aftermarket replacement number in your service manual with the numbers in the Part Number Matrix. If any detail differs, confirm fitment before ordering.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or intermittent tell-tale stream, overheating alarms or reduced cooling performance. Inspection may reveal blades that are cracked, brittle, melted or missing pieces.
How often should I replace the impeller?
Inspect the impeller as part of routine maintenance. Replacement intervals vary with engine use and operating conditions; more frequent service may be appropriate for engines used in saltwater or sandy and silty environments.
Is this part the same as the original OEM version?
This is an aftermarket replacement, not an OEM component. It is listed as a replacement for the referenced OEM numbers and is supplied with the components shown in the What’s in the Box section.
OEM vs. aftermarket?
This listing is for an aftermarket replacement. Compare the dimensions, replacement numbers and complete engine fitment information before installation.
Shipping speed and cost?
Typical transit is 5–15 days. Standard shipping is free, and expedited options appear at checkout where available.
Warranty and returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. Returns are accepted within the standard return window when the item is unused and in its original condition. Contact support for current policy details and return instructions.
Safety & Important Information
- Verify the original part number, dimensions and complete engine fitment information before purchase.
- Do not operate the engine without an adequate water supply.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended when you are not familiar with lower-unit or water-pump service.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts designed for dependable service in real-world operating conditions.
- Fast Global Fulfillment — Free standard delivery is available to most regions, typically within 5–15 days.
- Manufacturer-Direct Value — Fair pricing with attention to materials and quality control.
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