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SeaSierra

Water Pump Impeller Housing – Fits Mercury/Mariner 40-60 HP (Replaces 14334A3, 812966A12)

$42.00

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Orders are typically processed within 1–2 business days.


U.S. orders usually arrive within 6–15 days, depending on stock location and destination.


International delivery times may vary due to customs processing.


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

Product Details

This aftermarket Water Pump Impeller Housing is engineered as a robust replacement for Mercury and Mariner 40-60 HP 2-stroke and 4-stroke outboard engines from 1991 to the present. It ensures proper cooling system function by securing the water pump impeller.

It provides a direct interchange for Mercury part numbers 14334A3 and 812966A12, Quicksilver 14334A3, and Sierra 18-3578, offering a reliable fit and performance.

  • Installs as a direct OEM-equivalent replacement, requiring no modifications.
  • Constructed from a durable cast metal alloy to withstand the marine environment.
  • Produced in an ISO9002 certified factory (JLM Marine) to ensure consistent quality.

Part Number Matrix

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

Brand Part Number Superseded By Notes
Mercury 14334A3 812966A12 Original part number.
Mercury 812966A12 Current OEM part number.
Quicksilver 14334A3 OEM-tier aftermarket brand.
Sierra 18-3578 Aftermarket equivalent.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This housing fits a wide range of Mercury and Mariner outboards. Please verify your engine's serial number against the ranges provided to ensure an exact match. Note: This part will NOT fit Mercury Bigfoot models on 2-stroke engines manufactured during the 1991–1995 period.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Mercury 30 EFI 30 4-Stroke 2009 and up 14334A3 3-cylinder, Serial # 1C109093 & Up
Mercury 40 40 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P094500 THRU 0P206999
Mercury 40 40 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0T178500 THRU 0T598999
Mercury 40 CARB 40 4-Stroke 2006 and up 14334A3 3-cylinder, Serial # 0P401000 & Up
Mercury 40 CARB 40 4-Stroke 2006–2008 14334A3 3-cylinder, Serial # 1B227000 THRU 1B344306
Mercury 40 CARB 40 4-Stroke 2008–2009 14334A3 3-cylinder, Serial # 1C000001 THRU 1C018825
Mercury 40 CARB 40 4-Stroke 2009 and up 14334A3 3-cylinder, Serial # 1C018826 & Up
Mercury 40 EFI 40 4-Stroke 2009 and up 14334A3 3-cylinder, Serial # 1C043417 & Up
Mercury 40 EFI 40 4-Stroke 2006–2007 14334A3 3-cylinder, Serial # 0P401000 THRU 0P515896
Mercury 40 EFI 40 4-Stroke 2006–2008 14334A3 3-cylinder, Serial # 1B227000 THRU 1B344398
Mercury 40 EFI 40 4-Stroke 2008–2009 14334A3 3-cylinder, Serial # 1C000001 THRU 1C043416
Mercury 40 EFI 40 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P153500 THRU 0P400999
Mercury 40 EFI 40 4-Stroke 2006–2007 14334A3 4-cylinder, Serial # 0P401000 THRU 0P515896
Mercury 40 EFI 40 4-Stroke 2006–2008 14334A3 4-cylinder, Serial # 0T409000 THRU 1B344306
Mercury 40 EFI 40 4-Stroke 2008–2009 14334A3 4-cylinder, Serial # 1C000001 THRU 1C050251
Mercury 40 EFI 40 4-Stroke 2007 and up 14334A3 4-cylinder, Serial # 0P515897 & Up
Mercury 40 EFI 40 4-Stroke 2009 and up 14334A3 4-cylinder, Serial # 1C050252 & Up
Mercury 40 EFI Jet 40 4-Stroke 2009 and up 14334A3 4-cylinder, Serial # 1C051324 & Up
Mercury 40 Jet 40 4-Stroke 2004 and up 14334A3 Serial # 0P325500 & Up
Mercury 40 Jet 40 4-Stroke 2005 and up 14334A3 Serial # 0T980000 & Up
Mercury 40 Jet 40 4-Stroke 1999–2004 14334A3 Serial # 0P094500 THRU 0P325499
Mercury 40 Jet 40 4-Stroke 1999–2005 14334A3 Serial # 0T178500 THRU 0T979999
Mercury 45 Jet 45 2-Stroke 1994–1995 14334A3 3-cylinder, Serial # 0D000750 & Up
Mercury 45 Jet 45 2-Stroke 1999–1998 14334A3 Serial # 0G760300 THRU 0T129554
Mercury 45 Jet 45 2-Stroke 1994–1999 14334A3 Serial # 0P017000 THRU 0P094499
Mercury 50 50 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P094500 THRU 0P206999
Mercury 50 50 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0T178500 THRU 0T598999
Mercury 50 EFI 50 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P153500 THRU 0P400999
Mercury 50 EFI 50 4-Stroke 2006–2007 14334A3 4-cylinder, Serial # 0P401000 THRU 0P515896
Mercury 50 EFI 50 4-Stroke 2006–2008 14334A3 4-cylinder, Serial # 0T409000 THRU 1B344306
Mercury 50 EFI 50 4-Stroke 2008–2009 14334A3 4-cylinder, Serial # 1C000001 THRU 1C050251
Mercury 50 EFI 50 4-Stroke 2007 and up 14334A3 4-cylinder, Serial # 0P515897 & Up
Mercury 50 EFI 50 4-Stroke 2009 and up 14334A3 4-cylinder, Serial # 1C050252 & Up
Mercury 50 50 2-Stroke 1991–1997 14334A3 3-cylinder, USA, Serial # 0D000750-0G589999
Mercury 50 50 2-Stroke 1991–1997 14334A3 3-cylinder, Belgium, Serial # 9683055-99773099
Mercury 55 55 2-Stroke 1996–1997 14334A3 3-cylinder, USA, Serial # 0D000750 & Up
Mercury 55 55 2-Stroke 1996–1997 14334A3 3-cylinder, Belgium, Serial # 9741042 & Up
Mercury 55 55 2-Stroke 2004 and up 14334A3 3-cylinder, Serial # 0P325500 & Up
Mercury 55 55 2-Stroke 2005 and up 14334A3 3-cylinder, Serial # 0T980000 & Up
Mercury 55 55 2-Stroke 1998–2004 14334A3 3-cylinder, Serial # 0G760300 THRU 0T979999
Mercury 55 55 2-Stroke 1994–2004 14334A3 3-cylinder, Serial # 0P017000 THRU 0P325499
Mercury 60 60 2-Stroke 1991–1995 14334A3 3-cylinder (Std, not Bigfoot), USA, Serial # 0D000750 & Up
Mercury 60 60 2-Stroke 1991–1995 14334A3 3-cylinder (Std, not Bigfoot), Belgium, Serial # 9683055 & Up
Mercury 60 60 2-Stroke 2004 and up 14334A3 3-cylinder, Serial # 0P325500 & Up
Mercury 60 60 2-Stroke 2005 and up 14334A3 3-cylinder, Serial # 0T980000 & Up
Mercury 60 60 2-Stroke 1998–2005 14334A3 3-cylinder, Serial # 0G760300 THRU 0T979999
Mercury 60 60 2-Stroke 1994–2004 14334A3 3-cylinder, Serial # 0P017000 THRU 0P325499
Mercury 60 Bigfoot 60 2-Stroke 1998–2005 14334A3 3-cylinder, Serial # 0G760300 THRU 0T979999
Mercury 60 Bigfoot 60 2-Stroke 1994–2004 14334A3 3-cylinder, Serial # 0P017000 THRU 0P325499
Mercury 60 60 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P094500 THRU 0P206999
Mercury 60 60 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0T178500 THRU 0T598999
Mercury 60 EFI 60 4-Stroke 1999–2006 14334A3 4-cylinder, Serial # 0P153500 THRU 0P400999
Mercury 60 EFI 60 4-Stroke 2006–2007 14334A3 4-cylinder, Serial # 0P401000 THRU 0P515896
Mercury 60 EFI 60 4-Stroke 2006–2008 14334A3 4-cylinder, Serial # 0T409000 THRU 1B344306
Mercury 60 EFI 60 4-Stroke 2008–2009 14334A3 4-cylinder, Serial # 1C000001 THRU 1C050251
Mercury 60 EFI 60 4-Stroke 2007 and up 14334A3 4-cylinder, Serial # 0P515897 & Up
Mercury 60 EFI 60 4-Stroke 2009 and up 14334A3 4-cylinder, Serial # 1C050252 & Up
Mercury Formula 60 60 4-Stroke 2009 and up 14334A3 Serial # 1C104574 & Up

Technical Specs

Product Type
Water Pump Impeller Housing
Installation
Direct OEM replacement
Housing Material
Cast metal alloy
Housing Color
Silver/metallic
Other Technical Attributes
Produced in ISO9002 certified factory (JLM Marine)

What’s in the Box

When purchased as part number 14334A3, you will receive:

  • 1 x Water Pump Impeller Housing (14334A3)

When purchased as complete kit 46-812966A12, you will receive:

  • 1 x Impeller (47-19453T)
  • 1 x Plate (19700A2)
  • 1 x Housing (14334A3)
  • 1 x Base (46-812966A7)
  • 1 x Coupler/Guide Tube (859770/859770-1/893857)
  • 2 x Washer (12-858234)
  • 1 x Gasket Upper (27-822189)
  • 1 x Gasket Lower (27-19701)
  • 1 x Impeller Key
  • 1 x O-Ring

Installation Notes

  1. Disconnect the negative battery cable and position the outboard in the neutral gear.
  2. Carefully unbolt and remove the lower unit (gearcase) from the engine's midsection. Keep track of all hardware.
  3. Unbolt the existing water pump assembly to access the old housing and impeller. Note the orientation of all parts.
  4. Thoroughly clean the mating surfaces on the gearcase and driveshaft, removing any old gasket material or debris.
  5. Install the new housing and other kit components in the reverse order of removal. Ensure the impeller key is correctly seated.
  6. Lubricate the inside of the new housing and the impeller with a marine-safe lubricant.
  7. Torque all bolts to the manufacturer's specified values to prevent leaks and ensure a secure fit.
  8. Reinstall the lower unit, carefully aligning the driveshaft, shift shaft, and water tube.
  9. Once assembled, reconnect the battery and test the engine using a water source (flushing muffs) to verify proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I know if this housing fits my specific engine?

The best way is to verify your engine's model, year, and serial number against the detailed compatibility table above. This part is a direct cross-reference for OEM part number 14334A3 and its successor, 812966A12.

What are the signs of a failing water pump housing?

Visible signs include cracks, deep scoring, warping, or melting on the housing's interior or exterior. Performance symptoms include an overheating engine at idle or low speeds, or a weak or intermittent water stream from the "tell-tale" outlet.

How often should I replace my water pump components?

As a general maintenance guideline, it is recommended to inspect the impeller and housing annually. Plan to replace the full water pump kit every 2-3 years or every 200-300 hours of operation, whichever comes first, especially if you operate frequently in saltwater or silty conditions.

Does this fit Mercury Bigfoot models?

This part fits many 60 HP Bigfoot models from 1994 onwards, as shown in the compatibility table. However, it specifically excludes 2-stroke Bigfoot models made between 1991 and 1995. Always double-check your serial number range before ordering.

My original part number is 14334A3. Will this work?

Yes. Mercury Marine has officially superseded part number 14334A3 to 812966A12. This housing is the correct component for applications calling for either of those part numbers.

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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