Water Pump Impeller Kit – Fits Mercury/MerCruiser 35-300 HP (Replaces 8M0100526, 47-43026Q06)

$31.00

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Water Pump Impeller Kit – Fits Mercury/MerCruiser 35-300 HP (Replaces 8M0100526, 47-43026Q06) is backordered and will ship as soon as it is back in stock.

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Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller Kit provides a complete solution for servicing the cooling system on a wide range of Mercury/Mariner outboards from 35-300 HP and MerCruiser Alpha One Gen 2 sterndrives (serial #0D469859+). Designed for longevity and optimal performance, it ensures your engine maintains proper operating temperature.

It serves as a direct interchange for Mercury/Quicksilver parts 8M0100526 and 47-43026Q06, as well as Sierra 18-3265 and UANOFCN 8M0100526.

Engineered as a direct-fit replacement for easy installation.
Features a durable neoprene marine rubber impeller for improved water flow and cooling.
Includes all necessary gaskets, o-rings, and seals for a complete overhaul.

Part Number Matrix

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

Brand	Part Number
Mercury / Quicksilver	8M0100526
Mercury / Quicksilver	47-43026Q06
Sierra	18-3265
UANOFCN	8M0100526

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mariner outboards, this kit fits various 2-stroke and 4-stroke models. Please check your serial number range where noted.

For MerCruiser sterndrives, this kit is compatible with Alpha One Gen 2 units with serial numbers 0D469859 and higher.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
Mercury	BigFoot/Command Thrust	40-60	4-Stroke	8M0100526, 47-43026Q06
Mercury	BigFoot	60	2-Stroke	8M0100526, 47-43026Q06	Serial #0D000750 and above
Mercury	FourStroke	75-115	4-Stroke	8M0100526, 47-43026Q06	All models
Mercury	FourStroke	150	4-Stroke	8M0100526, 47-43026Q06	All models
Mercury	Standard	70-90	2-Stroke	8M0100526, 47-43026Q06	Serial #0A996142 and above
Mercury	Standard	100-125	2-Stroke	8M0100526, 47-43026Q06	4 cylinder models with pump cover screws without insulators
Mercury	OptiMax	200/225/250	2-Stroke	8M0100526, 47-43026Q06	3.0L V6 models
Mercury	Verado		4-Stroke	8M0100526, 47-43026Q06	L4 & L6 models with 4.80" & 5.44" diameter gearcases
Mercury	Various Outboard Models	35-300	2-Stroke & 4-Stroke	8M0100526, 47-43026Q06	Model specific - verify application
MerCruiser	Alpha One Gen 2			8M0100526, 47-43026Q06	Serial #0D469859 and above
MerCruiser	Gear Housing Drive-2.33:1			8M0100526, 47-43026Q06	USA-0T625304/BEL-0P216185 and up

Technical Specs

Product Type: Water Pump Impeller Kit
Installation: Direct replacement
Housing Material: Non-asbestos gasket, Neoprene Marine Rubber Impeller and O-Ring, Stainless Steel Plate
Housing Color: Black/Silver
Other Technical Attributes: Designed for improved water flow rate and cooling efficiency

What’s in the Box

1 x Water Pump Impeller (8M0025709)
1 x Drain Screw Gasket (830749)
1 x Seal Ring Gasket (8172771)
1 x Impeller Gasket (8M0050720)
1 x Impeller Key (8M0032833)
2 x O-Ring (0.796 in. x 0.139 in.) (21836)
1 x O-Ring (0.921 in. x 0.139 in.) (90196)
1 x Face Seal (8M2014338)
1 x Face Seal Setting Tool (818769)
1 x Water Pump Faceplate (8172761)
1 x Quad Ring (455771)

Installation Notes

Disconnect the battery and ensure the engine is off and cool.
Place the lower unit in a suitable stand after draining the gearcase oil.
Remove the propeller and disconnect the shift linkage.
Unbolt and carefully lower the gearcase from the engine midsection.
Locate and unbolt the water pump housing.
Remove the old impeller, gaskets, wear plate, and seals. Clean all mating surfaces thoroughly.
Install the new components from the kit in the reverse order of removal. Lightly grease the new impeller and seals.
Ensure the impeller key is correctly seated and rotate the driveshaft clockwise while installing the housing to set the impeller vanes.
Torque all bolts to the manufacturer’s specified values.
Reassemble the lower unit, reconnect the shift linkage, and refill with fresh gearcase oil.
Re-install the propeller and test the engine in the water, ensuring a steady stream of water from the tell-tale.

Troubleshooting & FAQ

How do I know if my water pump impeller is failing?

Common signs of a worn or damaged impeller include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and a noticeable decrease in engine performance. A visual inspection during routine maintenance may also reveal cracked, brittle, or missing vanes on the impeller.

Will this kit fit my MerCruiser Alpha One Gen 2 drive?

Yes, this kit is specifically designed for MerCruiser Alpha One Generation II sterndrives with a serial number of 0D469859 and above. Please verify your drive's serial number before ordering.

What is the recommended replacement interval for a water pump impeller?

For most recreational boats, it is recommended to inspect the impeller annually and replace it every 1-2 years, or every 100-200 hours of operation, whichever comes first. Usage in saltwater or sandy/silty conditions may require more frequent replacement.

The kit includes multiple O-rings. How do I know which one to use?

The different sized O-rings are specific to variations in the water pump housing and driveshaft over the years. Match the old O-rings from your unit to the new ones in the kit to ensure a correct fit for your specific model.

I have a 150 HP Mercury FourStroke. Is this the right kit?

Yes, this kit is listed as compatible with all models of the Mercury 150hp FourStroke outboard. As always, it is a good practice to double-check your existing part numbers if possible.

What is the purpose of the face seal setting tool?

The included face seal setting tool (818769) is critical for properly installing the new face seal (8M2014338) to the correct depth without damaging it, ensuring a watertight seal between the pump and driveshaft.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in 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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