Water Pump Impeller Service Kit – Mercury/Mariner 2-Stroke 4HP, 4.5HP, 7.5HP & 9.8HP (1975–1985), Replaces OEM 47-89981Q1
Water Pump Impeller Service Kit – Mercury/Mariner 2-Stroke 4HP, 4.5HP, 7.5HP & 9.8HP (1975–1985), Replaces OEM 47-89981Q1 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Service Kit – Mercury/Mariner 2-Stroke 4HP, 4.5...
Water Pump Impeller Service Kit – Mercury/Mariner 2-Stroke 4HP, 4.5HP, 7.5HP & 9.8HP (1975–1985), Replaces OEM 47-89981Q1 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Pump Impeller Service Kit is intended for selected Mercury and Mariner 2-stroke outboard applications rated at 4HP, 4.5HP, 7.5HP and 9.8HP from approximately 1975 through 1985. The application uses a driveshaft connection with a 0.456-inch inner diameter. Always confirm the engine model and serial-number range before ordering.
This impeller service kit is listed as a replacement for Mercury OEM part 47-89981Q1. Catalog references identify the corresponding impeller as part 89810 and distinguish it from the similar 0.438-inch-inside-diameter application associated with OEM reference 47-89980T1.
- Designed as a replacement impeller service kit for the listed Mercury and Mariner 2-stroke applications.
- Neoprene rubber impeller with a brass hub, as specified for this replacement component.
- Suitable for water-pump maintenance when the existing housing and related components are serviceable.
Part Number Matrix
Use the references below to compare the application with your original part. These numbers identify the replacement application and should not be used without confirming the engine details.
| Brand or Reference | Part Number | Application Note |
|---|---|---|
| Mercury OEM | 47-89981Q1 | Primary OEM reference for the 0.456-inch-inside-diameter application |
| Mercury impeller reference | 89810 | Impeller identified with the applicable water-pump service-kit listing |
Engine & Model Compatibility
The catalog application is limited to the following general Mercury and Mariner 2-stroke outboard ratings and production period. Horsepower and year alone may not identify every application; verify the complete engine model and serial number before installation.
| Brand | Engine Type | Rated HP | Stroke | Approximate Years | OEM Reference | Fitment Detail |
|---|---|---|---|---|---|---|
| Mercury / Mariner | Outboard | 4 | 2-Stroke | 1975–1985 | 47-89981Q1 | 0.456-inch impeller inside diameter application |
| Mercury / Mariner | Outboard | 4.5 | 2-Stroke | 1975–1985 | 47-89981Q1 | 0.456-inch impeller inside diameter application |
| Mercury / Mariner | Outboard | 7.5 | 2-Stroke | 1975–1985 | 47-89981Q1 | 0.456-inch impeller inside diameter application |
| Mercury / Mariner | Outboard | 9.8 | 2-Stroke | 1975–1985 | 47-89981Q1 | 0.456-inch impeller inside diameter application |
Technical Specs
- Product Type
- Water pump impeller service kit
- Installation
- Replacement installation in the existing water-pump assembly
- Impeller Inside Diameter
- 0.456 inches
- Dimensions
- Approximately 32mm diameter × 14.4mm height (1.26in × 0.57in)
- Material
- Neoprene rubber with brass hub
- Number of Blades
- 6
- Warranty
- Refer to the applicable order and warranty policy
What's in the Box
- 1 × Water pump impeller service-kit component
Important: The available catalog evidence identifies the application as an impeller service kit. It does not establish that a water-pump housing, wear plate, gasket set or other hardware is included. Inspect the package received before beginning the repair.
Installation Notes
- Switch off the engine, remove the ignition key and follow the manufacturer's safety procedure.
- Remove the lower unit or gearcase according to the engine service manual.
- Remove the water-pump cover and inspect the housing, wear surfaces, key and fasteners.
- Remove the old impeller and note the direction of the vanes.
- Clean the housing and mating surfaces. Replace worn or damaged water-pump components before reassembly.
- Install the replacement impeller with the correct key and with the vanes oriented in the direction specified by the service manual.
- Use only a lubricant approved for the application if lubrication is required during installation.
- Reassemble the pump and lower unit, tightening fasteners to the manufacturer's specifications.
- Run the engine only in an appropriate water supply or test tank and confirm a strong cooling-water discharge before normal operation.
Troubleshooting & FAQ
How do I confirm this impeller fits my Mercury or Mariner engine?
Match the engine brand, 2-stroke configuration, horsepower, approximate production year and complete serial number with the manufacturer's service information. Also compare the original impeller's inside diameter. The application described here uses a 0.456-inch inside diameter and is listed for 4HP, 4.5HP, 7.5HP and 9.8HP engines from approximately 1975–1985.
What is the difference between the 0.456-inch and 0.438-inch applications?
The 0.456-inch application uses a different driveshaft connection from the similar 0.438-inch application. Do not substitute between them based only on horsepower or appearance. Compare the original part, driveshaft and engine identification before ordering.
Does this listing include a complete water-pump housing?
No complete housing is identified by the available product information. This listing is for the impeller service-kit component. Inspect the water-pump housing, wear surfaces, key and gaskets, and replace any worn parts that are not serviceable.
How often should a water-pump impeller be replaced?
Replacement intervals depend on operating hours, storage conditions and whether the engine is used in saltwater, sand or silt. Follow the engine manufacturer's maintenance schedule and replace the impeller sooner if cooling-water flow weakens or the engine shows signs of overheating.
What are common signs of a failing impeller?
Possible signs include reduced or intermittent tell-tale flow, overheating at idle or low speed, visible cracking or brittleness, damaged vanes, or an impeller that has taken a permanent set after extended storage.
Is this an OEM part?
This is an aftermarket replacement component. Mercury OEM reference 47-89981Q1 is provided for application and interchange identification only; Mercury is not the manufacturer of this aftermarket item.
Safety & Important Information
- Verify the engine model, serial number, original impeller and inside diameter before ordering.
- Do not run an outboard without an adequate water supply.
- Replace damaged or excessively worn pump components before returning the engine to service.
- Professional installation is recommended when lower-unit removal or water-pump service is unfamiliar.
- Product images and dimensions may vary slightly from the original component; application and dimensional checks remain the buyer's responsibility.
About Sea Sierra
- Marine Replacement Parts — Replacement components for maintenance and repair of marine equipment.
- Application-Focused Listings — Part references and fitment information are provided to help you compare your original component.
- Support for Product Questions — Contact support with your engine model, serial number and original-part details when application information is needed.
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