Aftermarket Water Pump Impeller for Mercury 4–9.8 HP 2-Stroke Outboards – Replaces 47-89981
Aftermarket Water Pump Impeller for Mercury 4–9.8 HP 2-Stroke Outboards – Replaces 47-89981 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.
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Aftermarket Water Pump Impeller for Mercury 4–9.8 HP 2-Stroke Outbo...
Aftermarket Water Pump Impeller for Mercury 4–9.8 HP 2-Stroke Outboards – Replaces 47-89981 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller is listed for selected Mercury and Mariner 2-stroke outboard engines from 4 to 9.8 HP. It is designed to replace a worn impeller in the water pump and help restore proper cooling-water circulation. Always compare your original part number, engine model, serial number, and impeller dimensions before ordering.
Reference numbers associated with this impeller include Sierra 18-3039, Mercury 47-89981, Mercury 47-65957, Mercury 47-39074, CEF 500314, and GLM 12270. These references should be used for identification and comparison; verify the complete engine application before installation.
- Replacement impeller for the outboard water pump housing.
- Neoprene impeller with a brass hub.
- Six-blade design for water circulation through the cooling system.
Part Number Matrix
Use the following manufacturer and aftermarket references to help compare the part with your original impeller.
| Brand | Part Number |
|---|---|
| Sierra | 18-3039 |
| Mercury | 47-89981 |
| Mercury | 47-65957 |
| Mercury | 47-39074 |
| CEF | 500314 |
| GLM | 12270 |
Engine & Model Compatibility
The applications below are the listed compatibility references for this impeller. Confirm the exact engine model, serial-number range, original part number, and dimensions before purchase.
| Brand | Model | Rated HP | Stroke | Reference Part No. | Application Notes |
|---|---|---|---|---|---|
| Mercury | 1-Cylinder | 4 | 2-Stroke | 47-89981 | Serial number 2278851 and up; USA models |
| Mercury | 1-Cylinder | 4.5 | 2-Stroke | 47-89981 | 0.456-inch internal diameter reference |
| Mercury | 40 | 4 | 2-Stroke | 47-89981 | Serial number 2278851 and up; 1-cylinder |
| Mercury | 45 | 4.5 | 2-Stroke | 47-89981 | 1-cylinder |
| Mercury | 60 | 6 | 2-Stroke | 47-89981 | Serial numbers 1916139 through 2529894 |
| Mercury | 7.5 HP | 7.5 | 2-Stroke | 47-89981 | 0.456-inch internal diameter reference |
| Mercury | 75 | 7.5 | 2-Stroke | 47-89981 | Confirm model and serial number |
| Mercury | 9.8 HP | 9.8 | 2-Stroke | 47-89981 | 0.456-inch internal diameter reference |
| Mercury | 110 | 10 | 2-Stroke | 47-89981 | Serial number 1865779 and up |
Exclusion: This impeller is listed as not compatible with 5 HP Mercury or Mariner engines. Do not rely on horsepower alone; compare the original part and all applicable engine details.
Technical Specs
- Product Type
- Water pump impeller
- Installation
- Replacement in the outboard water pump housing
- Material
- Neoprene with brass hub
- Number of Blades
- 6
- Dimensions
- Height: 14.40 mm; overall diameter: 32.00 mm; shaft diameter: 11.60 mm
- Internal Diameter
- 0.456 inch (11.58 mm)
- Weight
- 11 g (0.458 oz)
- Engine Type
- 2-stroke outboard
- Fitment Limitation
- Not listed for 5 HP Mercury or Mariner engines
What’s in the Box
- 1 × Water pump impeller
Installation Notes
- Disconnect the battery and remove or disconnect the spark-plug leads before beginning work.
- Place the outboard securely in a service position and remove the lower unit according to the engine service manual.
- Remove the water pump housing cover and take out the old impeller.
- Clean debris and residue from the water pump housing, plate, and surrounding passages.
- Inspect the housing, wear plate, key, and seals; replace damaged parts as required.
- Lightly lubricate the impeller and housing with a lubricant approved for the application. Do not use petroleum products that may damage neoprene.
- Install the impeller with the blades oriented in the direction established by the engine’s normal rotation.
- Reinstall the water pump housing and tighten its fasteners to the engine manufacturer’s specifications.
- Reattach the lower unit, aligning the driveshaft, shift shaft, and water tube carefully.
- Before operating the engine, verify that the cooling-water tell-tale flows properly and check for leaks or overheating.
Follow the service manual for your specific engine. Gearcase-oil draining and refilling requirements vary by model and should be performed as specified by the manufacturer.
Troubleshooting & FAQ
Will this impeller fit my 5 HP Mercury engine?
No. This application is listed as not compatible with 5 HP Mercury or Mariner engines. Compare your engine model, serial number, original part number, and impeller dimensions before ordering.
How can I confirm that this part fits my motor?
Compare the original impeller’s part number and dimensions with the references and specifications on this page. Check the complete engine model and serial-number range rather than relying on horsepower alone. Consult the engine service manual if the information does not match exactly.
What are the signs of a failing impeller?
Common signs include overheating at idle or low speed, weak or absent water flow from the tell-tale outlet, reduced cooling performance, and brittle, cracked, or broken impeller blades.
How often should an impeller be replaced?
Inspect the impeller at the interval specified in your engine’s service schedule. Frequent use in saltwater, sand, silt, or debris can increase wear and may require more frequent inspection or replacement.
Is this an OEM part?
No. This listing is for an aftermarket replacement impeller. The manufacturer and aftermarket reference numbers are provided for identification and fitment comparison.
What should I do if the cooling stream is still weak after installation?
Stop the engine and verify impeller orientation, housing installation, water-tube alignment, seals, the wear plate, and cooling passages. Do not operate the engine if it overheats. Refer to the service manual or consult a qualified marine technician.
Safety & Important Information
- Confirm the part number, dimensions, engine model, stroke, and serial-number range before ordering.
- This is an aftermarket replacement, not an OEM component.
- Disconnect the battery and spark-plug leads before service, and support the outboard securely.
- Professional installation is recommended when you are unfamiliar with lower-unit or water-pump service.
- Never operate an outboard that is overheating or lacks a proper cooling-water stream.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for dependable service in real-world conditions.
- Global Fulfillment — Shipping options and delivery estimates are shown at checkout based on the destination.
- Manufacturer-Direct Value — We aim to provide practical replacement parts at competitive prices.
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