Description

The Mercury MerCruiser Quicksilver Idler Pulley 864625T is an OEM serpentine belt pulley used on compatible MerCruiser V6 and V8 stern drive and inboard engines. It helps guide and maintain proper belt tracking across the accessory drive system.

Key Features

• Genuine Mercury/MerCruiser idler pulley
• Part number: 864625T
• 4.25″ / 4-1/4″ outside diameter
• 6-groove serpentine belt design
• Sealed bearing pulley construction
• Used on compatible Alpha and Bravo engine packages
• Helps maintain proper accessory belt alignment and tension

Engine Compatibility

Fits select 1998 and newer MerCruiser V6 and V8 marine engines, including 4.3L V6, 5.0L V8, 5.7L / 350 Mag, and 6.2L / MX 6.2L applications using this 6-groove serpentine pulley setup.

Serial Number Fitment Notice

Verify fitment by engine serial number, belt routing diagram, pulley diameter, and original pulley part number before ordering. Pulley fitment can vary by accessory bracket layout, belt system, engine model, and production range.

When This Part Needs Replacement

Replace this pulley if the bearing is noisy, rough, loose, seized, wobbling, cracked, corroded, or if the belt shows abnormal wear, squealing, tracking issues, or repeated belt failure.

Installation Notes

Inspect the serpentine belt, belt tensioner, adjacent pulleys, alternator pulley, power steering pulley, and bracket alignment during service. Replace the belt if it is glazed, cracked, frayed, oil-soaked, or worn.

Alternate/Superseded Part Numbers

Primary Mercury references: 864625T, 849296T, 57-8638764, and 57-862086. Common aftermarket interchange: Sierra Marine 18-15101.

Parts Desk Insight

A worn idler pulley can make a new belt fail quickly. If the pulley bearing feels rough or the belt is tracking off-center, replacing the pulley during belt service helps protect the full accessory drive system.

Shipping: Ships same or next day for fast Canada wide shipping.