Quicksilver – Low-Pressure Fuel Boost Pump | MerCruiser Fuel System | Marine-Grade Construction | 861155A3

Overview

If you’ve ever felt an engine hesitate as you throttle up, you know how unsettling it can be. Smooth, confident fuel delivery is the heartbeat of a good boating day, and this Quicksilver fuel boost pump is designed to bring that steady rhythm back. It’s one of those Mercury Marine parts you install and immediately appreciate — not because it draws attention to itself, but because your engine suddenly feels younger, steadier, and more eager to run.

Key Features

• Low-pressure fuel boost pump for select MerCruiser engines
• Includes pump, fittings, and wiring with multi-pin connector
• Ensures consistent fuel delivery to high-pressure components
• Built to Mercury Marine OEM standards
• Mercury Marine part number 861155A3

Engine & Boat Compatibility

• Used on select MerCruiser sterndrive and inboard engines
• Common across 4.3L, 5.0L, 5.7L, and various multi-port injection platforms
• Suitable for cruisers, runabouts, cuddy cabins, larger bowriders, and heavy-loaded family boats
• Works in both freshwater and coastal environments

Performance & Practical Benefits

Once installed, the pump delivers a steady, reliable flow of fuel that makes the engine feel tight and responsive. It helps prevent starvation during hard acceleration, sharp turns, or rough water — moments when under-fueling can lead to stumbling or hesitation. The boost pump assists the high-pressure system by feeding it exactly what it needs, keeping the whole fuel stream balanced and controlled.

The pump’s marine-grade construction gives it the durability it needs to live in a hot, vibrating engine compartment. The fittings seat cleanly, and the included wiring harness makes the electrical connection simple and secure. That clean fitment matters. When everything snaps into place the way it should, it takes the stress out of the job.

Once the engine fires up and settles into a smooth idle, the improvement is immediate. Throttle response sharpens, mid-range feels cleaner, and long runs become easier on the engine and the driver.

Why Buy OEM

Fuel components are unforgiving places to cut corners. Aftermarket pumps may produce inconsistent pressure, struggle under heat, or fail sooner than expected. A genuine Mercury Marine part is engineered to deliver reliable flow and hold up to real-world marine conditions.

With OEM, you get the right connector, the right pressure curve, the right flow rate, and the durability that keeps you away from costly fuel-system diagnostics. Experienced boaters know: fuel delivery is one area where OEM matters most.

FAQ

Q1: Which engines does this pump fit?

It fits various MerCruiser sterndrive and inboard engines that require a low-pressure boost pump.

Q2: What makes it better than aftermarket pumps?

OEM pumps maintain proper pressure and are built to withstand marine heat and vibration.

Q3: How do I confirm it’s correct for my setup?

Check your manual. If it calls for part number 861155A3, this is your pump.

Q4: Can it be used in saltwater?

Yes — its marine-grade design handles both environments well.

Q5: Is installation straightforward?

Yes, especially with the included wiring connector and fittings.