Water Pump Housing Kit for Mercury/Mariner 4, 4.5, 7.5 & 9.8 HP 2-Stroke (1975–1985) – Replaces OEM 47-89980T1
Water Pump Housing Kit for Mercury/Mariner 4, 4.5, 7.5 & 9.8 HP 2-Stroke (1975–1985) – Replaces OEM 47-89980T1 is backordered and will ship as soon as it is back in stock.
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Water Pump Housing Kit for Mercury/Mariner 4, 4.5, 7.5 & 9.8 HP...
Water Pump Housing Kit for Mercury/Mariner 4, 4.5, 7.5 & 9.8 HP 2-Stroke (1975–1985) – Replaces OEM 47-89980T1 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Housing Kit is a replacement water-pump service assembly for selected Mercury and Mariner 2-stroke outboards rated at 4, 4.5, 7.5, and 9.8 HP from 1975 through 1985. The kit is intended for applications using the 0.438-inch impeller inside diameter and the impeller associated with OEM reference 47-89980T1.
The catalog application identifies this configuration as a water pump housing kit that includes the housing-related service components needed to renew the pump assembly. Confirm the engine model, production year, existing housing, impeller dimensions, and OEM reference before ordering.
- Complete water pump housing kit for specified Mercury/Mariner 2-stroke applications.
- Designed for applications using a 0.438-inch impeller inside diameter.
- Supplied with the housing, impeller, wear plate, O-rings, and seal listed below.
- Aftermarket replacement; not an original Mercury component.
Part Number Matrix
Use the following reference to compare this kit with the applicable manufacturer part number.
| Brand | Part Number | Reference Type |
|---|---|---|
| Mercury | 47-89980T1 | OEM application reference |
Engine & Model Compatibility
Fitment must be confirmed against the exact engine model and year. The application information below is limited to the catalog range associated with OEM reference 47-89980T1.
| Brand | Engine Type | Rated HP | Stroke | Years | OEM Reference | Application Note |
|---|---|---|---|---|---|---|
| Mercury/Mariner | Outboard | 4 | 2-Stroke | 1975–1985 | 47-89980T1 | Uses 0.438-inch impeller inside diameter |
| Mercury/Mariner | Outboard | 4.5 | 2-Stroke | 1975–1985 | 47-89980T1 | Uses 0.438-inch impeller inside diameter |
| Mercury/Mariner | Outboard | 7.5 | 2-Stroke | 1975–1985 | 47-89980T1 | Uses 0.438-inch impeller inside diameter |
| Mercury/Mariner | Outboard | 9.8 | 2-Stroke | 1975–1985 | 47-89980T1 | Uses 0.438-inch impeller inside diameter |
Technical Specifications
- Product Type
- Water pump housing kit
- Application
- Mercury/Mariner 2-stroke outboards
- Rated Horsepower
- 4, 4.5, 7.5, and 9.8 HP
- Application Years
- 1975–1985
- Impeller Inside Diameter
- 0.438 inch
- Installation
- Replacement water pump service assembly
- Part Status
- Aftermarket replacement, not OEM
What’s in the Box
- 1 x Water pump sleeve
- 1 x Water pump impeller
- 1 x Wear plate
- 1 x O-ring
- 1 x O-ring
- 1 x Water pump seal
Component identifiers may vary by production batch or packaging. Compare the supplied parts with the removed assembly before installation.
Installation Notes
- Disconnect the battery and remove the spark plug leads before servicing the outboard.
- Place a drain pan beneath the gearcase and drain the lower-unit lubricant according to the service manual.
- Remove the fasteners securing the gearcase to the midsection, then lower the gearcase carefully.
- Remove the water pump housing and note the orientation of the impeller, key, wear plate, seals, and gaskets.
- Clean the mating surfaces and remove old gasket material, corrosion, and debris.
- Install the supplied wear plate, seals, O-rings, and related pump components in the same orientation as the original assembly.
- Install the impeller on the driveshaft with the drive key correctly positioned. Lubricate the pump components as recommended by the engine service manual.
- Reinstall the housing and tighten its fasteners to the manufacturer's specified torque.
- Reattach the gearcase and refill the lower unit with the correct lubricant.
- Run the engine only in water or with an approved flushing device, then verify a steady cooling-water stream and check for leaks.
Troubleshooting & FAQ
How do I confirm that this kit fits my engine?
Confirm that your outboard is a Mercury or Mariner 2-stroke rated at 4, 4.5, 7.5, or 9.8 HP, produced during 1975–1985, and that the existing water-pump application uses OEM reference 47-89980T1 and a 0.438-inch impeller inside diameter. The exact model designation and service-manual information should be checked before ordering.
Is this an impeller-only kit?
No. This listing is for a water pump housing kit. It includes the water-pump service components listed in the package contents rather than an impeller alone.
What are common signs of a worn water-pump assembly?
Possible symptoms include a weak or absent tell-tale stream, overheating, steam, reduced cooling-water flow, or visible damage to the impeller, housing, wear plate, or seals. Stop operation if the engine overheats and inspect the cooling system.
Should the impeller and housing be replaced together?
Replacing worn pump components together can help restore the intended sealing and pumping surfaces. Inspect the driveshaft key, housing, wear plate, seals, and mating surfaces during service and replace any damaged parts.
Is anything else needed for installation?
Depending on the condition of the engine and the service procedure, additional items may be required, such as lower-unit lubricant, suitable marine lubricant, replacement fasteners, or gaskets not included in this package. Follow the engine manufacturer's service instructions.
Is this an OEM component?
No. This is an aftermarket replacement kit intended for the stated application. The OEM number is provided only as an application reference.
Safety & Important Information
- Verify the exact model, horsepower, stroke, year, OEM reference, and impeller dimensions before purchase.
- Do not operate an outboard without an adequate water supply for cooling.
- Use the engine service manual for torque values, sealing procedures, gearcase removal, and final testing.
- Professional installation is recommended if you are unfamiliar with lower-unit or water-pump service.
- This product is an aftermarket replacement and is not manufactured by Mercury or Mariner.
About Sea Sierra
- Marine Replacement Parts — Practical aftermarket components for routine marine service and repair.
- Application-Focused Listings — Compatibility information is organized by engine type, horsepower, stroke, year, and reference number.
- Service Support — Review the application details and compare the original assembly before installation.
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