57-861757Q Serpentine Belt for MerCruiser 4.3L 5.0L 5.7L 6.2L 350 Mag 377 Scorpion | JLM Marine

57-861757Q Serpentine Belt for MerCruiser 4.3L 5.0L 5.7L 6.2L 350 Mag 377 Scorpion

This serpentine belt is engineered for MerCruiser sterndrive V6 and V8 engines, including 4.3L, 5.0L, 5.7L, 6.2L, 350 Mag, and 377 Scorpion models. Designed to deliver reliable power transmission across a wide range of serial number applications from 1996 through 2005, this belt ensures consistent performance for your marine engine.

Direct Replacement for: MerCruiser OEM part numbers 57-861757, 57-861757Q, 861757, 861757Q, and Sierra 18-15115. This aftermarket replacement meets OEM specifications to keep your engine running smoothly.

• Precision-engineered 97.28" serpentine belt for optimal fit
• Compatible with both fresh water cooled (FWC) and raw water cooled (RWC) configurations
• Aftermarket replacement built to OEM standards for reliable performance

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 × 97.28" Serpentine V-Belt

Installation Guide

1. Disconnect the battery to ensure safety before beginning work on your engine.
2. Locate the serpentine belt routing diagram on your engine or consult your service manual for the correct path.
3. Using a belt tensioner tool or appropriate wrench, release tension on the old belt and carefully remove it from all pulleys.
4. Inspect all pulleys and tensioners for wear, damage, or misalignment before installing the new belt.
5. Route the new 97.28" serpentine belt around each pulley following the diagram, ensuring proper seating in each groove.
6. Release the tensioner slowly to apply proper tension to the new belt; verify it sits correctly on all pulleys.
7. Rotate the crankshaft by hand one full revolution to confirm the belt tracks properly without slipping or misalignment.
8. Reconnect the battery and start the engine briefly, listening for any unusual noises or squealing.
9. Shut down the engine and perform a final visual inspection to ensure the belt is seated correctly and under proper tension.

Troubleshooting & FAQ

Q: How do I confirm this serpentine belt fits my MerCruiser engine?
A: Check the compatibility table above for your engine model, displacement, and serial number range. Verify your engine's serial number falls within the listed ranges (1996-2005 models) and confirm the OEM part number 57-861757Q matches your original belt.

Q: What are the signs that my serpentine belt needs replacement?
A: Common symptoms include squealing or chirping noises during startup or acceleration, visible cracks or glazing on the belt surface, fraying edges, or accessory components (alternator, water pump) not functioning properly. Replace immediately if you notice any of these signs.

Q: How often should I replace the serpentine belt on my MerCruiser?
A: MerCruiser recommends inspecting the serpentine belt every 100 hours of operation or annually. Typical replacement intervals range from 300-500 hours or every 3-5 years, depending on operating conditions. Always replace if wear or damage is visible during inspection.

Q: Will this belt fit both fresh water cooled and raw water cooled configurations?
A: Yes, this 97.28" serpentine belt is compatible with both FWC (fresh water cooled) and RWC (raw water cooled) MerCruiser engines within the specified serial number ranges.

Q: What's the difference between OEM and aftermarket serpentine belts?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.