Mercury – Alternator Belt | High-Output Charging System | Rubber Composite | 8M0178243

Overview

Anyone who spends real time on the water knows how quickly a great day can turn if your charging system stops doing its job. That quiet confidence you feel when you fire up the engine, check your gauges, and see everything responding just the way it should — that feeling matters. It means your gear is working, your battery is charging, and you’re free to focus on the horizon instead of the “what-ifs.”

The Quicksilver 8M0178243 Alternator Belt brings that confidence back. Built for the powerful charging demands of Mercury’s V10 and V12 platforms, it keeps your 12-volt system steady and dependable, whether you’re offshore chasing a rip line or easing into the dock after a long day. It’s a small part with a big job, and when it’s doing that job right, you’ll barely think about it — which is exactly how it should be.

Key Features

• Maintains proper alternator function and battery charging
• Designed for Mercury 5.7L V10 and 7.6L V12 outboards
• Precision-fit replacement for the factory-installed belt
• Durable rubber composite construction for long service life
• Built to handle high-output alternator loads in marine conditions
• For all 12-volt battery systems used on these engines

Engine & Boat Compatibility

Compatible with:

• Mercury 5.7L V10 350–400hp outboards
• Mercury 7.6L V12 500hp SeaPro outboards
• Mercury 7.6L V12 600hp Verado outboards

Common on:

• Offshore center consoles
• Dual and triple-engine sport boats
• Heavy-duty commercial and utility boats
• Cruising boats relying on strong charging capacity

Performance & Practical Benefits

A good alternator belt doesn’t call attention to itself — it just runs tight, smooth, and steady. That’s exactly what this Mercury Marine part is built for. Once installed, you’ll notice how cleanly the alternator responds at idle, how the belt stays quiet under load, and how reliably it holds tension even after long, hot runs.

The rubber composite construction resists cracking, glazing, and the stretching that often shows up in cheaper aftermarket belts. That means fewer surprises and fewer times you’ll pop the cowl to investigate a squeal or charging drop. When you’re relying on a high-output alternator to power electronics, pumps, lighting, and everything else onboard, having a belt you trust makes a real difference.

It’s also an easy part to replace, making it a smart piece of preventive maintenance. Many boaters swap theirs annually just for peace of mind — and that’s never a bad call.

Why Buy OEM

Choosing a genuine Mercury Marine part is really about protecting the investment sitting on your transom:

• Exact fitment designed for V10 and V12 pulley systems
• Correct material composition for marine heat cycles and alternator load
• Longer service life compared to aftermarket belts
• Maintains optimal charging output
• Meets all Mercury Marine durability and performance specs

When you’re running a premium engine, the small parts matter just as much as the big ones. OEM keeps everything working the way Mercury engineered it.

FAQ

Q1: Which engines does this alternator belt fit?

It fits Mercury 5.7L V10 outboards and 7.6L V12 Verado and SeaPro outboards using 12-volt systems.

Q2: What makes this better than an aftermarket belt?

OEM belts match Mercury’s tension, load, and heat requirements — aftermarket options often don’t last as long or run as quietly.

Q3: How can I confirm it’s the right belt for my engine?

Check your owner’s manual or verify that your engine is a V10 5.7L or V12 7.6L model. If so, this is the correct Mercury Marine part.

Q4: Is it suitable for both saltwater and freshwater boats?

Absolutely — the construction holds up in any marine environment.

Q5: Is installation straightforward?

Yes, most boat owners with basic tools can replace the belt in minutes. Just follow Mercury’s tensioning instructions.