UANOFCN Water Pump Impeller Kit 8M0113799 for Mercury 30–125 HP — Neoprene Impeller & SS Wear Plate

UANOFCN 8M0113799 water pump impeller kit is a complete replacement assembly designed to restore cooling flow on compatible Mercury 30–125 HP outboard engines.

This impeller kit supplies the core components needed to rebuild the lower unit water pump used on a range of Mercury and Sierra outboards. Packaged components include a neoprene impeller, stainless wear plate, seals, gaskets, screws and housing parts, so you get the common wear items in one purchase. The kit matches several OEM numbers and is intended for preventive maintenance or mid-life rebuilds when cooling performance drops.

Which outboard engines will this kit fit?

This assembly is compatible with many Mercury Marine outboards in the 30–125 HP range but fit depends on exact model and year. Cross-reference the OEM numbers printed below with your engine parts list or serial plate before ordering. If you are unsure, provide your engine model and serial number to confirm compatibility.

• Replaces Mercury numbers: 46-8M0113799, 46-43024A7, 43024A4, 43024A5, 43024A6, 43026T9
• Also replaces Sierra part: 18-3688
• Intended for select Mercury 30–125 HP outboards — verify model/year

What parts are included in the kit and what are they made of?

The kit bundles the impeller with the typical mating parts needed for a rebuild so you don’t have to source multiple small items. Materials are chosen for corrosion resistance and durability in a marine environment. The combination helps re-establish a sealed pumping chamber and correct impeller fitment.

• Neoprene impeller for flexible blade action
• Stainless steel wear plate for corrosion resistance
• Nylon PA66 tube, non-asbestos gasket, housing, pump cover and drive key
• Two seals, several gaskets and four mounting screws included

How do I know when to replace my water pump impeller?

Signs of a failing impeller include reduced engine operating temperature stability, overheating, or low water discharge from the telltale. Mechanical wear, torn blades, or a hardened impeller rubber typically mean replacement is needed. Regular replacement on a service schedule prevents cooling system failure while on the water.

• Look for damaged, cracked, or missing impeller blades
• Noticeable drop in cooling-water flow or engine overheating
• Replace as part of routine seasonal maintenance

Are there installation tips or precautions I should follow?

Installation requires basic marine-mechanic tools and familiarity with lower-unit disassembly. Take care to align the drive key and seals correctly, and replace gaskets to ensure a watertight assembly. If you lack experience, a marine service technician can fit the kit to recommended torque and sealant specs.

• Confirm engine model and serial before starting work
• Lubricate impeller lightly for easier installation and fit
• Replace all seals and gaskets supplied; tighten screws to spec

Who is this for: This UANOFCN impeller kit is aimed at boat owners, DIY marine technicians and professional mechanics who maintain Mercury outboard engines and need an economical, ready-to-install rebuild kit. It’s useful for seasonal maintenance, mid-life pump rebuilds, or emergency repairs where OEM-equivalent replacement components are required. Always check your engine’s model, year and serial number to confirm fit, and consult a professional if you’re unsure about installation.