SeaSierra Outboard Water Pump Rebuild Kit for Mercury 30–60 HP — Complete impeller, seals & gaskets

The SeaSierra 812966A12 Outboard Water Pump Kit is a full rebuild set engineered to restore cooling performance on Mercury 4-stroke 30–60 HP outboards.

This kit gathers all primary components needed to replace a worn or leaking gearcase water pump and return reliable raw-water flow to your lower unit. Designed to match OEM specifications and fit a range of Mercury horsepower models, the set includes impeller, housing parts, seals, gaskets, and hardware — everything a routine pump rebuild requires. Below you’ll find concise answers to common buyer questions, clear lists of included parts, and guidance on who benefits most from this kit.

What parts are included in the SeaSierra 812966A12 kit?

The kit is comprehensive so you won't need to source multiple small parts separately. It covers the internal impeller and the external mating pieces that commonly wear during normal use.

• Housing 14334A3 and Water Pump Base Assembly 812966A7
• Impeller 19453T with Guide Tube 893857 and Key 19699
• Seals and O-rings: Seal 830749 and O-Ring 805726
• Gaskets and faceplate: Lower Gasket 19701, Gasket 822189, Faceplate 19700A2
• Washers and small hardware: Washer 12-858234, Washer 8M0204720

How do I know this kit fits my Mercury outboard?

This rebuild kit is specified for many Mercury 4-stroke outboards in the 30 to 60 HP range. It replaces multiple OEM part numbers and common aftermarket equivalents to simplify compatibility checks.

• Compatible with Mercury 30HP, 35HP, 40HP, 50HP, 60HP 4-stroke engines
• Replaces OEM numbers: 46-812966A12, 46-812966A10, 46-14334A3, and related series
• Also fits aftermarket references such as Sierra 18-3690 and GLM 12124

When should I replace my outboard water pump with this kit?

Swap the pump components if you notice reduced water discharge, overheating warnings, or visible deterioration of the impeller. Many owners perform a rebuild as preventative maintenance every few seasons or after extended storage.

• Signs to replace: low water stream from the telltale, overheating, or cracked impeller
• Recommended intervals: inspect annually; replace impeller every 1–3 years depending on use
• Includes common wear parts so a single service visit can fully refresh the pump

What tools and skills are needed to install this rebuild kit?

Basic mechanical ability and common marine tools cover most installations; however, lower-unit removal and correct torqueing are required for a proper seal. If you’re unfamiliar with outboard servicing, a qualified marine mechanic can install the kit quickly and ensure gaskets and seals seat correctly.

• Typical tools: socket set, screwdrivers, gasket scraper, marine grease
• Time estimate: 1–3 hours for experienced DIYers; longer if lower unit removal is needed
• Tip: replace all gaskets and seals included in the kit to prevent leaks

Who is this for: The SeaSierra 812966A12 kit is aimed at boat owners, marinas, and technicians who maintain Mercury 4-stroke outboards in the 30–60 HP range and want an all-in-one repair pack. It’s suited for preventative maintenance, seasonal rebuilds, and mid-life repairs when the impeller, housing, or seals show wear. If you need OEM-equivalent replacements without hunting multiple part numbers, this kit consolidates the necessary components into a single serviceable package.