Water Pump Impeller Kit – Fits Mercury/Mariner 40-250 HP and MerCruiser Alpha One Gen 2 (Replaces 47-43026Q06, 8M0100526)

Product Details

This Water Pump Impeller Kit provides a comprehensive solution for servicing the cooling systems on a wide range of Mercury and Mariner outboards (40–250 HP, 1992–present) and MerCruiser Alpha One Gen 2 stern drives. Engineered for reliability, it ensures your engine maintains optimal operating temperature, preventing overheating and potential damage.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury/MerCruiser 47-43026Q06 and 8M0100526, Sierra 18-3265 and 18-3214, and Mallory Marine 9-48313.

• Installs directly into the lower unit's water pump housing.
• High-durability neoprene impeller designed for marine environments.
• Includes essential gaskets, seals, and hardware for a complete service.

Part Number Matrix

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

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mariner outboards, this kit fits a wide variety of 4-stroke and 2-stroke models from 40 HP to 250+ HP, including Verado, Pro XS, and an extensive range of EFI engines. Verify your serial number range where applicable.

For MerCruiser stern drives, this kit is specifically for Alpha One Generation 2 models within the specified serial number range.

Technical Specs

Product Type

Water Pump Impeller Kit

Installation

Engine/Drive Mount

Fuel Type

Gasoline

Housing Material

Metal Alloys

Impeller Material

Neoprene

Dimensions

4.92 × 4.33 × 2.36 inches (125 × 110 × 60 mm)

Weight

1.26 pounds (0.57 kg)

Maximum HP Rating

275 HP

Engine Type

4-Stroke (also compatible with select 2-Stroke models)

Operation Mode

Manual

Manufacturer

Various (aftermarket replacement)

OEM Part Number

47-43026Q06/8M0100526

What’s in the Box

• 1 x Neoprene Impeller (Replaces 47-43026-T2 / 47-43026Q02)
• 1 x Face Plate (Replaces 8172761)
• 1 x Water Pump Gasket (Replaces 430331 / 8172771)
• 1 x Impeller Key
• 1 x O-ring
• 1 x Face Seal
• 1 x Tool (Note: Tool inclusion varies by manufacturer)

Note: Some aftermarket kits may include additional gaskets, seals, or O-rings not pictured.

Installation Notes

1. Disconnect the battery and remove the engine cowling.
2. Shift the engine into forward gear to simplify driveshaft re-engagement.
3. Remove the bolts securing the lower unit (gearcase) to the engine midsection.
4. Carefully lower and remove the gearcase from the outboard.
5. Unbolt and remove the water pump housing cover to access the impeller.
6. Remove the old impeller, key, gaskets, and wear plate. Clean all mating surfaces thoroughly.
7. Install the new wear plate, gaskets, and impeller key.
8. Slide the new impeller onto the driveshaft, turning the shaft clockwise to bed the vanes correctly inside the housing.
9. Re-install the water pump housing and torque bolts to manufacturer specifications.
10. Lightly grease the driveshaft splines and reinstall the lower unit, ensuring the water tube and shift shaft align correctly.
11. Once secured, test the engine using a water supply (flushing muffs) to confirm proper water pump operation.

Troubleshooting & FAQ

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.