Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957)
Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957) 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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Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces...
Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Pump Impeller – Fits Mercury 4, 4.5, 6, 7.5, 9.8 HP (Replaces 47-89981, 47-65957) is a crucial component for maintaining your outboard's cooling system. It is designed for specific Mercury and Mariner 2-stroke outboard motors, including 4, 4.5, 6, 7.5, and 9.8 HP models. Proper fitment depends on a drive shaft diameter of 0.456 inches.
It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 47-89981, 47-65957, 47-39074, Sierra 18-3039, and Mallory 9-45305.
- Engineered with a durable neoprene body and a corrosion-resistant brass hub.
- Designed for a precise fit on models with a 0.456-inch inside diameter shaft.
- Recommended for replacement during scheduled annual water pump service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury | 47-89981 |
| Mercury | 47-65957 |
| Mercury | 47-39074 |
| Sierra | 18-3039 |
| Mallory | 9-45305 |
| GLM | 12270 |
| CEF | 500314 |
Engine & Model Compatibility
Confirm your engine model and serial number in the table below to ensure fitment.
For Mercury/Mariner owners, it is critical to verify your drive shaft diameter. This impeller fits the 0.456-inch shaft models and will NOT fit 5 HP variants or other shaft sizes.
| Brand | Model | Rated HP | Stroke | Serial / Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 4 HP 1-Cylinder (USA) | 4 | 2-Stroke | 47-89981 | Inside diameter 0.456 inch | |
| Mercury | 4.5 HP 1-Cylinder | 4.5 | 2-Stroke | 47-89981 | Inside diameter 0.456 inch | |
| Mercury | 40 (4 HP) 1-Cylinder | 4 | 2-Stroke | Serial number 2278851 and up | 47-89981 | Inside diameter 0.456 inch |
| Mercury | 60 (6 HP) | 6 | 2-Stroke | Serial numbers 1916139–2529894 | 47-89981 | Inside diameter 0.456 inch |
| Mercury | 110 (10 HP) | 10 | 2-Stroke | Serial number 1865779 and up | 47-89981 | Inside diameter 0.456 inch |
| Johnson/Evinrude | 20 HP (200) | 20 | 2-Stroke | 1973–1981 | Verified compatibility from JLM Marine |
Technical Specs
- Product Type
- Water Pump Impeller
- Material
- Neoprene with Brass Hub
- Number of Blades
- 6
- Overall Diameter
- 32.00 mm (1.26 in)
- Height
- 14.40 mm (0.57 in)
- Shaft Insert Diameter
- 11.60 mm (0.456 in)
- Weight
- 11 g (0.39 oz)
- Color
- Black
What’s in the Box
- 1 x Water Pump Impeller (47-89981/47-65957/47-39074)
Installation Notes
- Disconnect the negative battery cable before starting work.
- Remove the lower unit (gearcase) from the outboard motor.
- Locate and unbolt the water pump housing.
- Carefully remove the old impeller, noting the original orientation of the blades.
- Clean any debris or corrosion from the inside of the housing and wear plate.
- Lightly grease the new impeller and housing interior with marine grease.
- Slide the new impeller onto the driveshaft while turning the shaft clockwise to bed the blades correctly.
- Reassemble the water pump housing with new gaskets (not included) and torque bolts to specification.
- Reinstall the lower unit, ensuring the driveshaft and shift shaft are correctly aligned.
- Reconnect the battery and test the engine in water, confirming a steady stream from the tell-tale.
Troubleshooting & FAQ
How do I confirm this impeller fits my Mercury engine?
The most critical factor is the driveshaft diameter. This impeller has a shaft insert diameter of 11.60 mm (0.456 inches). Please measure your shaft or old impeller hub to confirm. Do not rely solely on the engine model, as manufacturers sometimes use different parts in the same model year.
Will this part fit my 5 HP Mercury Mariner engine?
No. Manufacturers explicitly state this impeller will not fit 5 HP Mercury engines, which typically use a different driveshaft diameter. Purchasing this part for a 5 HP model will result in improper fitment.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet, or a high-temperature alarm. If you notice any of these signs, inspect your cooling system immediately.
How often should I replace my impeller?
For preventative maintenance, it is recommended to replace your impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can be shorter if you frequently operate in sandy, silty, or saltwater environments.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It has been built to OEM-level specifications with comparable materials. The part is manufactured in an ISO 9002 facility and is batch-inspected for consistency and quality.
What are the shipping speed and cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most orders; expedited options may appear at checkout where available, depending on your location.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal marine use. If an issue arises, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. Please see our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears on a compatibility list—do not purchase.
- This is an aftermarket replacement component, not an Original Equipment Manufacturer (OEM) part.
- Professional installation is highly recommended for safety, performance, and to prevent engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions with a typical transit time of 5–15 days.
- Manufacturer-Direct Value — Our parts deliver fair pricing without compromising on materials or quality control.
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