Mercury – Water Pump Impeller | Cooling System Component | Flexible Marine Elastomer | 89981

Overview

There’s something timeless about running an older Mercury two-stroke. Those light, dependable 3.9–9.8 horsepower outboards have powered fishing trips, camping weekends, and quiet shoreline cruises for generations. But even the toughest vintage motor relies on one small part to stay cool and keep running strong — the water pump impeller. The Quicksilver 89981 Water Pump Impeller brings fresh reliability to these classic engines, delivering the strong, steady cooling flow they need whether you’re idling along a creek bank or pushing across open water on a summer afternoon.

Key Features

• Designed for vintage Mercury 3.9–9.8 HP 2-cycle outboards
• High-flex marine elastomer construction ensures dependable cooling
• Bonded center insert prevents separation and protects water flow
• Engineered for strong flow rates and consistent temperature control
• Built to Mercury OEM specifications for older model outboards

Engine & Boat Compatibility

• Fits vintage Mercury 3.9–9.8 HP 2-cycle outboards
• Commonly used on:
  • Small aluminum fishing boats
  • Portable dinghies and tenders
  • Inflatable boats and canoes with clamp-on motors
  • Lightweight skiffs and utility boats
• Compatible with legacy Mercury water pump housings in the corresponding model range

Performance & Practical Benefits

A healthy cooling system can make all the difference in keeping a classic two-stroke alive and running its best. Over time, impellers lose flexibility, crack, or wear unevenly — especially in older motors that may sit for long periods between seasons. When that happens, water flow drops, and the engine begins running hotter than it should. The Quicksilver 89981 restores that cooling performance and helps keep these engines running cooler, smoother, and more reliably.

The marine-grade elastomer allows each vane to flex cleanly as it rotates through the housing, maintaining water pressure even at low idle or slow trolling speeds. This flexibility is important on smaller portable outboards, which often spend long periods running at variable RPMs. The bonded hub prevents the all-too-common failure where the vanes separate under load, instantly cutting off water flow — a serious risk on older engines.

With a fresh impeller installed, the cooling system delivers a strong, visible telltale stream and consistent water pressure. You’ll notice a steadier idle, quicker warm-up, and more confidence when running at higher throttle settings. Vintage Mercury engines are famous for their longevity, and a properly functioning pump is one of the most important steps in keeping them that way.

Why Buy OEM

Classic motors deserve parts made to the standards they were designed for. Aftermarket impellers may appear similar, but they often rely on cheaper rubber compounds that harden, crack, or deform more quickly — especially in engines used in sandy or silty shallows. An OEM Quicksilver impeller ensures correct diameter, correct vane shape, and correct flexibility, giving your vintage outboard the cooling performance it requires. When you’re preserving a motor that’s been running for decades, OEM is the safest and smartest choice.

FAQ

Q1: Which engines does the 89981 impeller fit?

It fits vintage Mercury 3.9–9.8 horsepower 2-cycle outboards.

Q2: Why is replacing the impeller important?

Impellers wear out with heat, time, and storage. Replacing them regularly prevents overheating and internal engine damage.

Q3: How do I confirm compatibility?

Check your model and horsepower range or reference your service manual for part number 89981.

Q4: Does this impeller work in saltwater?

Yes. The elastomer is designed for marine use when properly flushed after saltwater operation.

Q5: Is installation manageable for DIY boaters?

Absolutely. With basic hand tools and a service manual, most owners can perform an impeller change successfully.