Water Pump Impeller Kit – Fits Mercury/Mariner 40–275HP & MerCruiser Alpha One Gen 2 (Replaces 47-43026Q06, 8M0100526)

Product Details

This aftermarket water pump impeller kit provides a complete solution for servicing the cooling systems on a wide range of Mercury/Mariner outboards (40–275HP) and MerCruiser Alpha One Gen 2 stern drives. It is designed to restore cooling performance for 4-stroke BigFoot/Command Thrust models, various 2-stroke engines, Verado outboards, and Alpha One Gen 2 drives from 1991 onward.

This kit serves as a direct replacement for Mercury part numbers 47-43026Q06, 8M0100526, 47-43026Q5, 47-43026T6, 47-43026T7, 47-43026T8, 47-43026T10, and 47-43026T11, as well as Sierra 18-3265.

• Engineered as a direct replacement for original equipment.
• Features a durable neoprene rubber impeller and a stainless steel housing.
• Includes gaskets, seals, O-rings, and installation components made for marine water-pump service.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket sources.

Engine & Model Compatibility

Confirm your engine model and serial number against the table below before ordering. Model, year, horsepower, stroke, and serial-number conditions should be considered together.

For Mercury/Mariner outboards, this kit fits the listed 2-stroke and 4-stroke models from 40HP to 275HP, including BigFoot, Command Thrust, EFI, and Verado series.

For MerCruiser stern drives, it is compatible with the listed Alpha One Gen 2 models manufactured from 1991 onward.

Technical Specs

Product Type

Water Pump Impeller Kit

Installation

Direct replacement for original equipment

Housing Material

Stainless steel; neoprene marine rubber impeller

Package Dimensions

15.3 × 10.3 × 5.4 cm (6.02 × 4.06 × 2.13 inches)

Weight

190 g (6.7 ounces)

Gasket Material

Non-asbestos

What’s in the Box

• 1 × Impeller (47-43026Q02)
• 1 × Impeller plate (817276)
• 1 × Impeller key (28-8M0032833)
• 1 × Seal ring gasket (26-45577)
• 1 × Impeller gasket (27-817277)
• 2 × O-rings (25-21836)
• 1 × Oil seal (26-816575A2)
• 2 × Drain screw gaskets (26-830749)
• 1 × Face seal setting tool (818769)

Installation Notes

1. Disconnect the battery and remove the lower unit from the outboard or stern drive.
2. Locate and unbolt the water pump housing.
3. Remove the old impeller, gaskets, wear plate, and seals, noting their orientation.
4. Thoroughly clean all mating surfaces and remove old gasket material or corrosion.
5. Install the new wear plate, gaskets, and seals supplied in the kit.
6. Insert the new impeller into the housing, rotating the driveshaft clockwise to bend the vanes into the correct position.
7. Reinstall the water pump housing, ensuring that all components are properly seated. Torque the bolts to the manufacturer’s specifications.
8. Reattach the lower unit to the engine and reconnect the battery.
9. Start the engine using a reliable water supply, such as flushing muffs or an appropriate test tank, and verify a strong, consistent stream from the telltale outlet.

Troubleshooting & FAQ

Safety & Important Information

• Verify the engine or drive model, serial number, and existing part number before ordering.
• Do not operate an engine without an adequate water supply.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended when you are unfamiliar with lower-unit or stern-drive service.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and intended for real-world marine conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or quality control.