SeaSierra Outboard Water Pump Kit for Mercury 30–60 HP — Complete Impeller, Housing & Seals

The SeaSierra 812966A12 outboard water pump kit is a complete replacement assembly engineered to restore cooling performance for Mercury 30–60 HP four-stroke lower units.

If your Mercury outboard is losing coolant flow or the lower unit shows signs of overheating, this SeaSierra kit supplies the commonly worn components needed to rebuild the water pump and get your engine back to reliable operation. The kit replaces the impeller, housing, seals, gaskets, and small fasteners that deteriorate with time, salt, and debris. It’s compatible with a range of Mercury Marine models and matches OEM part numbers, making it a practical choice whether you’re doing routine maintenance or repairing a failing pump.

Which Mercury engines will this SeaSierra kit work with?

This kit fits Mercury 4-stroke outboards in the 30, 35, 40, 50, and 60 horsepower classes that use the referenced lower unit pump layout. It’s designed as a direct replacement for multiple OEM part numbers, ensuring proper fit and function for those models. Check your engine’s manual or existing part numbers before ordering to confirm compatibility.

• Compatible with Mercury Marine 30HP, 35HP, 40HP, 50HP, 60HP four-stroke outboards
• Replaces OEM numbers: 46-812966A12, 46-812966A10, 46-14334A3, 46-14334A2, 46-14334A1
• Also replaces related OEM variants: 46-812966A6, A5, A4

What parts are included and how do they address common failure points?

The kit contains the primary wear items found in a water pump assembly, so you don’t have to source multiple components separately. Replacing the impeller and seals prevents leaks and restores water circulation through the engine’s cooling passages. The housing, faceplate, gaskets, guide tube, and fasteners ensure the rebuilt pump is sealed and aligned correctly.

• Included impeller 19453T and guide tube 893857 for restored flow
• Housing 14334A3 and faceplate 19700A2 to replace corroded components
• Seals, O-rings, gaskets (805726, 19701, 822189) to stop leaks
• Hardware: key 19699, seal 830749, washers and base assembly 812966A7

How difficult is installation and what tools or skills are needed?

Installation is a moderate DIY task for someone comfortable with basic marine mechanics; it typically requires removing the lower unit, swapping components, and reassembling with correct torque. If you’ve changed an impeller before, you’ll find the process familiar. For first-timers or if corrosion or damaged fasteners are present, professional help may save time and prevent leaks.

• Requires removal of lower unit from outboard for full access
• Common tools: socket set, screwdrivers, torque wrench, marine grease
• Plan for gasket sealant, alignment checks, and a bench to organize parts

Will this kit match OEM performance and warranties?

SeaSierra supplies aftermarket parts that mirror OEM fit and form for listed applications; the kit includes parts that replace both OEM and compatible aftermarket reference numbers. While SeaSierra parts are built to restore factory-like function, check your engine’s warranty terms before installation, as aftermarket replacement parts can affect coverage in some cases.

• Cross-references to OEM and aftermarket numbers for reliable interchangeability
• Designed to restore original water flow and sealing when installed correctly
• Verify manufacturer warranty policy before using aftermarket components

Who is this for: This SeaSierra 812966A12 water pump rebuild kit is aimed at boat owners, marine technicians, and DIY mechanics who operate Mercury 30–60 HP four-stroke outboards and need a full set of replacement pump components. It’s especially useful for routine maintenance intervals, pre-season service, or when diagnosing low coolant flow or lower-unit overheating. Choose this kit when you want a single-purchase solution that includes the impeller, housing, seals, gaskets, and related hardware to properly rebuild the pump assembly.