Mercury – Serpentine Belt | Engine Drive System | Rubber Composite | 865615Q08

Overview

There’s a certain comfort in hearing your engine hum the way it’s supposed to. When you ease the throttle forward and everything responds smoothly—no shudder, no strain—it reminds you why you trust the gear under your hatch. On older Bravo-series V6 and V8 engines, the serpentine belt plays a bigger role than most boaters realize. It ties the whole system together, keeping the alternator steady, the cooling flowing, and the boat feeling ready for the day ahead. This Mercury Marine part brings that calm reliability back, giving you confidence from the moment you fire up the engine.

Key Features

• Designed for 1999–2002 MerCruiser V6 and V8 Bravo engines
• Fits 305, 350, and 377 cubic inch configurations
• Intended for setups with a high-mounted alternator and removed power steering pump
• Built from durable marine-grade rubber composite
• Matches the original factory-installed belt
• Engineered for precise tension, steady tracking, and long-term reliability

Engine & Boat Compatibility

• Fits 1999–2002 MerCruiser MCM V6 and V8 Bravo engines
• Compatible with serial numbers 0L619000 through 0M343007
• Works with high-mounted alternator configurations
• Designed for engines where the power steering pump has been removed
• Common on performance boats, cruisers, older sport boats, and multi-purpose recreational vessels
• Suitable for both sterndrive and inboard setups using this specific routing pattern

Performance & Practical Benefits

On engines from this era, a properly matched serpentine belt makes a noticeable difference. With the right belt in place, accessories spin smoothly and predictably. You’ll feel steadier electrical output, more consistent steering assist if equipped, and stable cooling performance. Everything just feels “right,” especially when you accelerate or maneuver in tight spaces.

This Mercury Marine part fits naturally into the pulley system. You won’t struggle with tension or slip because it’s built to the exact dimensions the engine was designed for. As soon as it’s installed, the belt seats cleanly in the grooves, grabbing firmly without being overly tight. That clean engagement helps prevent squealing, reduced alternator output, and premature belt wear—issues common with off-brand replacements.

The rubber compound is formulated specifically for the marine environment, resisting heat cycling, moisture, and long run times. For boats that still see plenty of hours despite their age, that durability helps keep maintenance predictable and downtime minimal. More than anything, this belt keeps your engine feeling balanced and composed, which is something every boater can appreciate.

Why Buy OEM

With older engines, precision matters even more. Factory-original belts are engineered to match the engine’s exact load demands, groove spacing, and tension points. Aftermarket options may look similar, but slight deviations can create problems—slip, noise, heat spots, or rapid wear. An OEM belt gives you confidence that everything will line up, work smoothly, and last. It’s the kind of part you’d recommend to another boater at the dock because it saves time, protects your investment, and keeps the engine running the way Mercury intended.

FAQ Section

Q1: Which engines does this belt fit?

It fits 1999–2002 MerCruiser V6 and V8 Bravo engines within the serial range 0L619000–0M343007.

Q2: What makes this different from aftermarket belts?

The sizing, groove depth, and tension profile match the original exactly, resulting in smoother accessory operation and longer belt life.

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

Check your serial number, engine model (305, 350, or 377), and ensure your alternator is high-mounted and your power steering pump has been removed.

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

Yes, the marine-grade rubber is built for both environments.

Q5: Is installation easy?

Most boaters can install it using basic tools and the belt-routing diagram in the engine compartment or owner’s manual.