Mercury – Fuel Line Assembly | Fuel System | Gray Low-Permeation Hose | 8M0078629

Overview

There’s a certain comfort in the simple things — like the feel of a primer bulb firming up beneath your hand before you start the engine. That smooth resistance tells you fuel is moving the way it should, and for most boaters, that moment brings a quiet sense of readiness. The Mercury Fuel Line Assembly 8M0078629 is built around that exact feeling. Whether you’re gliding out for a calm morning run or heading home through a bit of wind and chop, this assembly keeps fuel flowing steady and predictable so you can focus on the water, not the equipment feeding your engine.

Key Features

• Five-sixteenth-inch inside diameter hose for consistent, dependable fuel flow
• Low-permeation hose construction helps reduce fumes and maintain fuel quality
• Mercury-engineered primer bulb provides strong, reliable priming pressure
• Gray heat-reflective exterior helps lower vapor-lock risk on hot days
• Flexible, marine-grade hose designed for long-term durability
• Compatible with a range of tank and engine connector styles
• Ideal for portable tanks, built-in fuel systems, and custom rigging routes

Engine & Boat Compatibility

• Fits Mercury and Mariner outboards using a universal five-sixteenth-inch fuel line
• Suitable for small to mid-range horsepower engines across many production years
• Works well for pontoons, skiffs, aluminum fishing boats, runabouts, tenders, and inflatables
• Adapts easily to various tank types when paired with the correct fittings

Performance & Practical Benefits

You’ll feel the quality right away. The primer bulb firms up cleanly and consistently — no spongy feel, no uneven pressure — just a confident squeeze that tells you the system is working properly. The hose runs smoothly through tight rigging pathways, bending around corners without kinking or collapsing. That flexibility makes a big difference in maintaining stable fuel flow when the boat rocks, turns sharply, or hits an unexpected patch of chop.

On warmer days, the gray exterior helps reflect sunlight and keep fuel temperatures more stable, reducing the risk of vapor lock. The low-permeation hose also cuts down on gasoline odor and slows evaporation, especially useful when the boat is stored under a cover or kept in a warm shed. Over the long haul, the hose remains flexible instead of stiffening or cracking, and the primer bulb retains its firm, dependable squeeze season after season. The result is smoother starts, steadier idle, and more reliable performance on the water.

Why Buy OEM

When it comes to fuel delivery, genuine Mercury Marine parts make all the difference. Every detail — from the hose blend to the valves inside the primer bulb — is engineered specifically for the demands of marine use. Aftermarket components may look similar, but they rarely match Mercury’s consistency, durability, or long-term performance. Choosing OEM ensures proper fitment, predictable operation, and the confidence that your fuel system will perform exactly the way your engine needs it to. It’s a smart choice for anyone who values trouble-free time on the water.

FAQ

Q1: Which engines does the 8M0078629 Fuel Line Assembly fit?

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

Q2: What sets this apart from aftermarket options?

Stronger priming, higher-quality hose materials, and engineering tailored specifically to Mercury’s performance standards.

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

Verify your current hose diameter and connector types. If you use a five-sixteenth-inch line, this assembly is typically a direct fit with the proper fittings.

Q4: Can this be used in both saltwater and freshwater?

Yes. The materials are designed for long-term durability in either environment.

Q5: Is installation straightforward for most boaters?

Absolutely. Once the correct connectors are attached, routing and securing the hose is simple.