Mercury – Fuel Pump | MerCruiser V8 GM Series | Marine-Grade Mechanical Pump | 861677T

Overview
Out on the water, nothing feels better than an engine that responds instantly—smooth, strong, and ready to run. Whether you’re pushing a big V8 through open chop or easing away from the dock with friends aboard, you want to know your fuel system is doing its job without hesitation. That’s where a dependable mechanical pump really earns its place. The Mercury Marine part number 861677T Fuel Pump is built for those classic V8 MerCruiser engines, delivering steady, reliable fuel flow that keeps your boat running the way it should. It’s the kind of part you install once and trust every time you turn the key.

Key Features

• Mechanical fuel pump engineered for V8 MerCruiser sterndrive and inboard engines

• Designed for General Motors 454 and 502 cubic-inch marine engine platforms

• Durable marine-grade construction built to handle heat, vibration, and moisture

• Factory-matched to Mercury Marine OEM specifications for consistent performance

• Provides precise, dependable fuel delivery for efficient combustion and strong throttle response

Engine & Boat Compatibility

• Fits V8 MerCruiser sterndrive and inboard engines made by General Motors

• Supports 454 CID and 502 CID MerCruiser engine models

• Ideal for cruisers, offshore boats, sport boats, cabin boats, and classic big-block setups

• Suitable for both leisure and heavier-duty marine applications

Performance & Practical Benefits
A mechanical pump may seem simple, but on a big-block marine engine, it’s absolutely essential. The 861677T provides the steady, controlled fuel flow these engines need to stay smooth at idle and strong under load. You’ll feel the difference when the throttle responds cleanly instead of stumbling or lagging. When you roll the power forward, the fuel supply stays steady and confident, giving your V8 that tight, powerful push you expect from a MerCruiser.

This fuel pump is engineered specifically for the marine environment. The internal components are built to handle constant vibration, fluctuating temperatures, and the demands of long hours on the water. The body feels solid and secure in your hand—heavy enough to inspire confidence, precise enough to install smoothly without wrestling it into place. Once installed, it maintains tight sealing and consistent flow, helping protect your engine from fuel starvation or lean-running conditions.

With an OEM match, the fit is exact, the mounting points are perfect, and the flow characteristics align with what Mercury designed. No guesswork, no adjustments—just a dependable pump that does what it’s supposed to.

Why Buy OEM
For something as vital as fuel delivery, sticking with genuine Mercury Marine parts is simply the smart choice. The 861677T is built to the same standards as the original factory pump, ensuring long-term reliability and proper fuel flow under all conditions. Aftermarket pumps might look similar but often vary in flow rate, pressure regulation, or material durability. That can lead to hard starting, inconsistent performance, or even engine damage over time. An OEM pump gives you the right performance the first time—and for many seasons after.

FAQ

Q1: Which engines does the Mercury 861677T Fuel Pump fit?
It fits V8 MerCruiser sterndrive and inboard engines made by General Motors, including 454 and 502 cubic-inch models.

Q2: What makes this pump different from aftermarket alternatives?
It’s engineered to Mercury Marine’s exact OEM specifications, ensuring proper flow, pressure, and durability for marine V8 engines.

Q3: How do I know if this is the correct replacement?
Check your service manual or existing pump for part number 861677T. If it matches, this is the correct pump.

Q4: Can this pump be used in saltwater and freshwater boats?
Yes—its marine-grade construction resists corrosion and performs reliably in both environments.

Q5: Is installation straightforward?
For most mechanically inclined boat owners, yes. Mounting and fueling connections are simple, but professional installation is always an option.