Mercury – Water Pump Repair Kit | Cooling System Rebuild | Multi-Piece OEM Kit | 89984Q5

Overview

Anyone who’s run an older Mercury or Mariner outboard — or one of the classic MerCruiser drives — knows how important a strong cooling system really is. These engines work through decades of tides, heat cycles, and long days on the water, and the hidden wear inside the water pump slowly adds up. When the telltale starts to weaken or the engine runs a bit warmer than you remember, that’s your cue. The Quicksilver 89984Q5 Water Pump Repair Kit brings everything back to center, giving your engine the water flow it needs to stay cool, reliable, and ready for another season of use. It’s a full reset for one of the most important systems on your boat.

Key Features

• Complete 14-piece OEM water pump repair kit
• Fits select Mercury and Mariner 65 HP 4-cylinder outboards
• Also fits MerCruiser I, R, MR, and Alpha sterndrives using short-vane impellers
• Includes gaskets, face plate, impeller, drive key, o-ring, and water guide tube
• Elastomer impeller vanes maintain flexibility across wide temperature swings
• Designed for high, consistent water flow and long-term durability
• Built to Mercury Marine OEM specifications for perfect fit and cooling protection

Engine & Boat Compatibility

This kit is engineered for a broad lineup of engines, including:

• 65 HP Mercury and Mariner 4-cylinder outboards
• MerCruiser sterndrives using short-vane impellers:
  • MerCruiser I
  • MerCruiser R
  • MerCruiser MR
  • MerCruiser Alpha

Common boat types using these engines and drives include:

• Classic fiberglass runabouts
• Vintage aluminum fishing boats
• Small cruisers
• Older family bowriders
• Utility workboats
• Boats restored or maintained with original MerCruiser systems

Performance & Practical Benefits

Over years of use, the components inside a water pump slowly wear: vanes stiffen, plates groove, seals weaken. That wear reduces water flow gradually, often so slowly you don’t notice until your engine starts idling hotter or steaming at the telltale. A full rebuild with the 89984Q5 kit restores the pump to its intended efficiency.

The impeller’s elastomer design keeps it flexible from early-spring cold starts to peak-summer heat. Fresh gaskets and the new face plate ensure every vane sweeps across a clean, smooth surface. The drive key helps the impeller maintain firm rotation, pushing water at the rate the engine was built for. It all adds up to quieter running, more stable temperatures, easier starts, and stronger confidence when you’re out on the water with family or friends.

The added durability of OEM parts is especially important for older outboards and sterndrives that have already seen years of use. Restoring the pump with a full kit, not just a single impeller, eliminates hidden weak points and helps protect the powerhead against overheating.

Why Buy OEM

With cooling systems, precision isn’t optional. Mercury’s OEM components match the material specs, geometry, and tolerances the engine was originally engineered around. Aftermarket kits may fit the housing, but they often lack the correct vane stiffness or plate hardness needed for proper water flow. Choosing an OEM kit means longer life, better performance, and fewer unexpected problems — especially important with older or classic engines you want to protect.

FAQ

Q1: Which engines does this kit fit?

It fits select Mercury and Mariner 65 HP 4-cylinder outboards and MerCruiser I, R, MR, and Alpha sterndrives that use short-vane impellers.

Q2: Why use a full repair kit instead of replacing only the impeller?

A full kit ensures the pump is restored completely, improving flow and preventing issues caused by worn plates or seals.

Q3: How do I confirm this is the correct part?

Check your engine model and confirm whether it uses a short-vane impeller. Your owner’s manual lists compatible part numbers.

Q4: Can this be used in freshwater and saltwater?

Yes — just flush the engine after saltwater use for best longevity.

Q5: Is installation straightforward?

With the proper tools and a service manual, most boat owners can complete this repair at home.

• Supersessions
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