Water Pump Impeller – Fits Mercury Marine 4-9.8 HP 2-Stroke Outboards (Replaces 47-89981)
Water Pump Impeller – Fits Mercury Marine 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.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Water Pump Impeller – Fits Mercury Marine 4-9.8 HP 2-Stroke Outboar...
Water Pump Impeller – Fits Mercury Marine 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 high-quality Water Pump Impeller – Fits Mercury Marine 4-9.8 HP 2-Stroke Outboards (Replaces 47-89981) is an aftermarket component engineered for a direct fit on various Mercury Marine 2-Stroke outboard motors, including 4, 4.5, 6, 7.5, and 9.8 HP models. It is designed to restore cooling system performance and prevent engine overheating.
This part serves as a direct cross-reference for several part numbers, including Sierra 18-3039, Mercury 47-89981, Mercury 47-65957, Mercury 47-39074, CEF 500314, and GLM 12270.
- Installs directly into the water pump housing.
- Constructed from durable neoprene with a brass hub for reliable service.
- Features 6 blades for efficient water circulation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Sierra | 18-3039 |
| Mercury | 47-89981 |
| Mercury | 47-65957 |
| Mercury | 47-39074 |
| CEF | 500314 |
| GLM | 12270 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner engines, this impeller fits a specific range of 1- and 2-cylinder models. Please check your engine's serial number and original part number to ensure a correct match.
| Brand | Model | Rated HP | Stroke | OEM Part No. | 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 | Inside diameter 0.456 inch |
| Mercury | 40 (4 HP) | 4 | 2-Stroke | 47-89981 | Serial number 2278851 and up, 1-Cylinder |
| Mercury | 45, 4.5 | 4.5 | 2-Stroke | 47-89981 | 1-Cylinder |
| Mercury | 60 (6 HP) | 6 | 2-Stroke | 47-89981 | Serial number 1916139 thru 2529894 |
| Mercury | 7.5 HP | 7.5 | 2-Stroke | 47-89981 | Inside diameter 0.456 inch |
| Mercury | 75 (7.5 HP) | 7.5 | 2-Stroke | 47-89981 | |
| Mercury | 9.8 HP | 9.8 | 2-Stroke | 47-89981 | Inside diameter 0.456 inch |
| Mercury | 110 (10 HP) | 10 | 2-Stroke | 47-89981 | Serial number 1865779 and up |
Technical Specs
- Product Type
- Water Pump Impeller
- Installation
- Direct replacement in 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
- Compatibility
- Not compatible with 5 HP Mercury Mariner engines
What’s in the Box
- 1 x Water Pump Impeller (47-89981)
Installation Notes
- Disconnect the spark plug leads and the battery for safety.
- Drain the gearcase oil from the lower unit.
- Unbolt and carefully detach the lower unit from the engine's midsection.
- Locate and unbolt the water pump housing cover.
- Remove the old impeller, paying attention to its rotational direction. Clean any debris from the housing.
- Lightly lubricate the new impeller and the inside of the housing with a marine-safe lubricant.
- Install the new impeller by pushing down while turning the driveshaft in the direction of engine rotation to bend the blades correctly.
- Reinstall the water pump housing and torque its bolts to the manufacturer's specification.
- Reattach the lower unit, ensuring the driveshaft, shift shaft, and water tube are aligned.
- Refill the lower unit with fresh gear oil before starting the engine.
Troubleshooting & FAQ
Will this impeller fit my 5 HP Mercury engine?
No, this impeller has an internal diameter of 0.456" and is specifically noted as not compatible with 5 HP Mercury Mariner engines. Always verify your part number and engine specifications before ordering.
How can I confirm this part fits my motor?
The best way is to compare your existing impeller's part number and dimensions to those listed here. Check the compatibility table for your engine model, HP, and serial number range. When in doubt, consult your engine's service manual.
What are the signs of a failing impeller?
Common signs of a worn or damaged impeller include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" cooling outlet, and finding brittle, cracked, or broken blades during inspection.
How often should I replace my impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1 to 2 years (or 100-200 hours of use), especially if operating in saltwater or sandy/silty conditions.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and quality.
What are the shipping speed & cost?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most regions; expedited options will appear at checkout where available.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their 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.
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