Mercury – Quicksilver Serpentine Belt Idler Pulley | For MerCruiser Engines | 807757T

Overview

Smooth, steady belt operation keeps your boat’s vital systems running right — and the Mercury Marine 807757T Quicksilver Idler Pulley helps make that happen. Designed for MerCruiser 4.3L, 5.0L, 5.7L, 6.2L, and 8.2L sterndrive and inboard engines made by General Motors, this OEM pulley guides the serpentine belt while maintaining proper tension and alignment. Made from a durable thermal resin with an integrated bearing, it’s built to handle constant load, heat, and vibration in marine conditions. It’s a simple replacement that helps keep your belt drive system quiet, stable, and efficient — just the way it should be.

Key Features

• Purpose: Maintains proper tension and alignment in serpentine belt systems.
• Compatibility: Fits MerCruiser 4.3L, 5.0L, 5.7L, 6.2L, and 8.2L engines by General Motors.
• Construction: Made from high-strength thermal resin for long service life and corrosion resistance.
• Bearing Design: Features a molded-in bearing for smoother, quieter operation.
• Dimensions: 3-inch pulley with six grooves for accurate belt tracking.
• Maintenance Tip: Inspect pulley bushings and serpentine belt for wear when replacing.

Engine & Boat Compatibility

• MerCruiser sterndrive and inboard engines with serpentine belt systems, including:
• 4.3L
• 5.0L
• 5.7L
• 6.2L
• 8.2L

Performance & Real-World Benefits

The 807757T idler pulley plays an essential role in keeping your belt drive system quiet, efficient, and reliable. A worn or failing pulley can cause squealing, belt vibration, or premature belt wear — all signs that it’s time for replacement.

This Mercury OEM pulley is engineered from reinforced thermal resin, a lightweight yet durable material that resists corrosion and deformation. Its sealed bearing is built into the pulley for smooth rotation, reducing friction and extending belt life. Once installed, it keeps your serpentine belt running true and steady, ensuring consistent power to your alternator, water pump, and steering system.

Why Choose Mercury OEM

The Quicksilver 807757T is a genuine Mercury Marine component, precision-engineered for your MerCruiser engine. Aftermarket pulleys may look similar but can use lower-grade plastics or loose-tolerance bearings that wear quickly under load.

Mercury OEM parts are tested in real marine environments to handle high torque, heat, and exposure to saltwater. The result is a pulley that runs smoothly, stays balanced, and lasts longer — the same one Mercury technicians trust on factory engines.

FAQ

Q1: What engines does this pulley fit?
It’s designed for MerCruiser 4.3L, 5.0L, 5.7L, 6.2L, and 8.2L sterndrive and inboard engines with serpentine belts.

Q2: What’s it made from?
It’s made of durable thermal resin with a molded-in bearing for long life and quiet operation.

Q3: When should it be replaced?
Replace it if you hear belt noise, see cracks, or notice the belt slipping or wearing unevenly.

Q4: Is installation simple?
Yes — it’s a direct OEM fit that installs easily using standard tools.

Q5: Why OEM instead of aftermarket?
Because Mercury OEM pulleys are precision-balanced, corrosion-resistant, and designed to perform reliably in harsh marine environments.