Mercury – Fuel Line Assembly | Fuel System | Gray Low-Permeation Hose | 8M0078627

Overview

If you’ve spent enough time on the water, you know the feeling — that first squeeze of the primer bulb that tells you everything’s right where it should be. The pressure builds smoothly in your hand, the engine feels ready, and the day already seems easier. The Mercury Fuel Line Assembly 8M0078627 is built around that simple, reassuring moment. Whether you’re easing out for a quiet drift or riding home through a bit of afternoon chop, this assembly keeps fuel flowing steady, clean, and consistent so you can stay focused on the water, not the equipment feeding your engine.

Key Features

• Five-sixteenth-inch inside diameter hose for dependable, even fuel delivery
• Low-permeation hose construction helps maintain fuel freshness and cut down fumes
• Mercury-engineered primer bulb provides firm, predictable priming pressure
• Gray heat-reflective exterior helps reduce vapor-lock risk
• Flexible, marine-grade hose built for long-term durability
• Works with a variety of engine and tank connector styles
• Ideal for portable tanks, built-in systems, and custom rigging layouts

Engine & Boat Compatibility

• Fits Mercury and Mariner outboards using universal five-sixteenth-inch fuel lines
• Suitable for small to mid-range horsepower engines across many model years
• Great fit for pontoons, runabouts, aluminum fishing boats, skiffs, tenders, and inflatables
• Adapts easily to different tank types once paired with the correct connectors

Performance & Practical Benefits

You feel the engineering the moment you prime it — the bulb tightens with a clean, confident squeeze, moving fuel the way it should. The hose routes smoothly through rigging tunnels, bends naturally around corners, and resists collapsing or kinking, even when the boat shifts through uneven water or weight moves around the deck. That flexibility helps maintain smooth fuel flow in real-world conditions.

On hot summer days, the gray coating reflects heat instead of absorbing it, which helps keep fuel temperature stable and reduces vapor-lock issues during long runs. The low-permeation hose reduces fuel odor and slows evaporation, which is especially useful if the boat sits stored under a cover or inside a garage. Over time, the hose remains flexible instead of cracking or stiffening, and the primer bulb keeps that same crisp firmness year after year. Everything works together to deliver easier starts, steadier idle, and more dependable performance on the water.

Why Buy OEM

Fuel delivery is one place where genuine Mercury Marine components make a noticeable difference. Each part — from the hose blend to the internal valves in the primer bulb — is engineered to Mercury standards for durability, reliability, and consistent performance. Aftermarket versions might look similar but typically fall short when it comes to priming strength, long-term flexibility, or hose quality. Choosing OEM means fewer headaches, cleaner fitment, and the kind of reliability seasoned boaters trust. It’s a smart choice for anyone who wants their outboard to run as smoothly as it was designed to.

FAQ

Q1: Which engines does the 8M0078627 Fuel Line Assembly fit?

It fits Mercury and Mariner outboards using a universal five-sixteenth-inch fuel line, once paired with the proper connectors for your tank and engine.

Q2: Why choose this over aftermarket fuel lines?

Mercury’s materials and primer bulb engineering offer stronger priming, better durability, and more reliable long-term performance.

Q3: How do I confirm it’s the correct replacement?

Check that your current system uses a five-sixteenth-inch line and identify your connector styles. With the proper fittings, this assembly is typically a direct replacement.

Q4: Can this be used for both saltwater and freshwater boating?

Yes. It’s designed to withstand long-term use in either environment.

Q5: Is installation simple?

Very. Add the correct connectors, route and secure the hose neatly, and installation is straightforward for most boaters.