UANOFCN Outboard Upper Water Pump Impeller Kit for Mercury 8–25 HP — Complete Repair Kit with Gaskets & Seals

This premium aftermarket repair kit contains the housing assembly, impeller, gaskets, o‑rings, face plates, plate set, key and related seals needed to restore the upper water pump on many Mercury outboard engines. It replaces OEM part numbers 99157T2, 85098A2 and 99157A2 and covers a range of Mercury 2‑stroke and 4‑stroke models from roughly 8.0 to 25 HP. Before ordering, confirm your outboard model and serial number to ensure fit and compatibility.

Which Mercury outboards will this kit fit?

This kit is built for a variety of small Mercury outboards. It covers several 2‑stroke sizes (15, 18, 20, 25 hp) and 4‑stroke applications (9.9, 15 hp), and aligns with the listed OEM part numbers for a straightforward replacement.

• Compatible with Mercury Marine 2‑stroke: 15 hp, 18 hp, 20 hp, 25 hp.
• Compatible with Mercury Marine 4‑stroke: 9.9 hp and 15 hp models.
• Replaces OEM numbers: 99157T2, 85098A2, 99157A2.
• Verify your engine model and serial number before purchase to avoid fitment errors.

How does the kit restore my outboard cooling system?

Replacing the upper pump assembly and impeller restores the impeller’s ability to circulate cooling water and re-establishes sealed surfaces for proper flow. New gaskets, o‑rings and face plates help prevent leaks while the included key and plate hardware ensure the assembly mounts correctly.

• New impeller re-establishes water flow through the engine cooling passages.
• Housing assembly and face plates replace worn mating surfaces to stop leaks.
• Gaskets and O‑rings provide fresh seals for long service life.
• Includes key and plates for correct mechanical alignment during reassembly.

What’s included and why those parts matter?

The kit is supplied with every component needed for an upper pump service so you don’t have to source parts separately. Each piece addresses common failure points in the upper pump assembly, minimizing downtime and ensuring a reliable rebuild.

• Pump housing assembly — replaces corroded or cracked housings.
• Impeller and face plates — restore pumping action and sealing faces.
• Gaskets, O‑rings, guide sleeve and key — ensure correct fit and leak prevention.
• Gear lube fill and vent screw O‑rings — refresh small seals often missed in partial kits.

How should I check compatibility before buying?

Because Mercury used varying configurations across years and models, match your engine’s model designation and serial number to the kit’s supported part numbers before purchase. If your outboard’s part number or serial doesn’t match, consult a dealer or the motor’s service manual.

• Locate the model and serial plate on the outboard housing or transom tag.
• Compare your OEM part number with 99157T2, 85098A2, 99157A2 listed for this kit.
• When in doubt, contact a Mercury dealer with your serial for verification.
• Keep a photo of the old pump and parts for reference during installation.

Who is this for: Boaters, DIY mechanics and marine technicians who need a full upper water pump rebuild for compatible Mercury outboards will find this UANOFCN kit useful. It’s aimed at owners of small to mid‑size Mercury engines who prefer a single purchase that contains all necessary components to complete the service correctly. Always confirm fitment with your engine details prior to ordering to ensure successful installation.