Water Pump Impeller – Fits Mercury/Mariner 15-50 HP (Replaces 47-8508910, 0755466)

$26.50 $42.00

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Water Pump Impeller – Fits Mercury/Mariner 15-50 HP (Replaces 47-8508910, 0755466) is backordered and will ship as soon as it is back in stock.

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You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

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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 aftermarket Water Pump Impeller – Fits Mercury/Mariner 15-50 HP (Replaces 47-8508910, 0755466) is a direct replacement for maintaining your engine's cooling system. It is engineered for a broad range of Mercury and Mariner 2-stroke and 4-stroke outboards from 15 HP to 50 HP, manufactured between 1974 and 2006, including specific XD, Bigfoot, SeaPro, and Mara models.

This component provides a direct cross-reference for multiple part numbers, including Mercury 47-8508910, 8M0204712, and Force/OMC 0755466, ensuring a precise fit for listed applications.

Easy to install as a direct OEM-equivalent replacement.
Features a durable neoprene housing and a brass hub for reliable performance in marine environments.
Includes the required drive key for a complete installation.

Part Number Matrix

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

Brand	Part Number
Mercury	47-8508910
Mercury	47-85089-10
Mercury	8M0204712
Mercury	47-85089-3
Mercury	850893
Mercury	8M0024502
Force/OMC	0755466
Sierra	18-3057
Mallory Marine	9-45303
GLM	89640
CEF	500315

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This impeller is designed for a variety of Mercury, Mariner, and Force outboards. Please check your specific model and year against the list to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	15 HP XD Bigfoot	15	2-Stroke	1984–2005	47-8508910
Mercury	18/20 HP XD	18/20	2-Stroke	1984–2005	47-8508910
Mercury	25 HP SeaPro, Mara, Super15	25	2-Stroke	1984–2006	47-8508910
Mercury	25 HP 3-cylinder	25	2-Stroke	1997+	47-8508910
Mercury	25/30/40 HP	25-40	4-Stroke	1998–2006	47-8508910
Mercury	30 HP 2-cylinder	30	2-Stroke	1994–1998	47-8508910
Mercury	30 JET	30	2-Stroke	1998	47-8508910
Mercury	40 HP 2-cylinder	40	2-Stroke	1994–1998	47-8508910
Mercury	40 HP 3-cylinder	40	2-Stroke	1997–1998	47-8508910
Mercury	50 HP 3-cylinder	50	2-Stroke	1998	47-8508910
Mercury	45/50 HP 4-cylinder	45/50	4-Stroke	1995–1999	47-8508910	Standard
Mercury	75 HP	75	2-Stroke	1999	47-8508910
Mercury	8 HP Bodensee (Intern)	8	2-Stroke	1984–2005	47-8508910	International model
Mercury	9.9 HP (323cc)	9.9	2-Stroke	1984–2005	47-8508910
Mercury	13.5 HP (International)	13.5	2-Stroke	1984–2005	47-8508910	International model
Mercury	30 HP EFI (3 Cyl)	30	2-Stroke	1997–2006	47-8508910
Mercury	40 HP Carb (3 Cyl)	40	2-Stroke	1997–2006	47-8508910
Mercury	40 EFI (3 Cyl)	40	2-Stroke	1997–2006	47-8508910
Mercury	40 ITALY	40	2-Stroke	1997–2006	47-8508910	Italian market model
Mercury	45 Bodensee	45	2-Stroke	1997–2006	47-8508910	International model
Mercury	50 BIGFOOT	50	2-Stroke	1997–2006	47-8508910

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Force	15-50 HP	15-50	2-Stroke	1984–1999	0755466	Force was acquired by Mercury

Technical Specs

Product Type: Water Pump Impeller
Installation: Direct OEM Replacement
Connection: Brass Hub with Drive Key
Housing Material: Neoprene with Brass Hub
Dimensions: Inner Hub Diameter: 16.00 mm, Outer Diameter: 73.00 mm, Width: 12.60 mm
Number of Blades: 6
Warranty: Varies by manufacturer (OEM: Factory warranty, Aftermarket: Typically 1 year)

What’s in the Box

1 x Water Pump Impeller (47-8508910)
1 x Drive Key

Installation Notes

Disconnect the battery and remove the engine cowling.
Drain the lower unit gear lube.
Remove the bolts securing the lower unit (gearcase) to the engine's midsection and carefully drop it down.
Locate the water pump housing, usually situated on top of the lower unit.
Unscrew the bolts holding the water pump housing cover.
Pry the old impeller off the driveshaft, being careful not to lose the drive key.
Clean the housing and inspect it for wear or damage. Replace the housing if deep grooves are present.
Lightly grease the new impeller and housing interior with marine grease.
Slide the new drive key into its slot on the driveshaft, then install the new impeller, turning the driveshaft clockwise to seat the blades correctly.
Reassemble the water pump housing, reattach the lower unit, and refill with fresh gear lube.
Reconnect the battery and test the engine with a water supply to ensure proper water flow.

Troubleshooting & FAQ

How do I know if this impeller fits my specific engine model?

The best way to confirm fitment is to check your original part number against our Part Number Matrix. If you don't have the original part, carefully review the Engine & Model Compatibility table and compare your engine's brand, HP, stroke, and year. When in doubt, message us with your engine's serial number.

What are the signs of a failing water pump impeller?

Common signs include a weak or non-existent "telltale" stream (the water stream exiting the engine), engine overheating alarms, and reduced engine performance. A dry-rotted, cracked, or worn impeller cannot pump water effectively.

How often should I replace my impeller?

As a preventative maintenance item, it is recommended to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Usage in saltwater or sandy/murky water may require more frequent replacement.

What does the included drive key do?

The drive key is a small metal piece that locks the impeller to the driveshaft, ensuring that the impeller spins with the shaft to pump water. It is a critical component that must be installed correctly.

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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