Serpentine Belt – Fits MerCruiser 4.3L, 5.0L, 5.7L V6/V8 Alpha Engines (Replaces 57-861758Q)

Vendor: JLM Marine
Availability: In Stock
Product Type: Belt
$63.00
$63.00
Subtotal: $63.00

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Serpentine Belt – Fits MerCruiser 4.3L, 5.0L, 5.7L V6/V8 Alpha Engines (Replaces 57 - 861758Q) - JLM Marine Boat Parts Limited

Serpentine Belt – Fits MerCruiser 4.3L, 5.0L, 5.7L V6/V8 Alpha Engines (Replaces 57-861758Q)

$63.00

Serpentine Belt – Fits MerCruiser 4.3L, 5.0L, 5.7L V6/V8 Alpha Engines (Replaces 57-861758Q)

$63.00

Serpentine Belt – Fits MerCruiser 4.3L, 5.0L, 5.7L V6/V8 Alpha Engines (Replaces 57-861758Q)

This replacement serpentine belt is designed for specific MerCruiser V6 and V8 Alpha sterndrive engines manufactured between 1996 and 1999. It is engineered to fit models equipped with standard cooling and a 5-3/4" power steering pulley, ensuring reliable performance of engine accessories.

This part is a direct replacement for Mercury/MerCruiser part numbers 57-861758, 57-861758Q, 861758, and 861758Q. It also replaces Sierra 18-15116 and Recmar RM57-861758Q.

  • Precise Fit: Engineered for MerCruiser 4.3L, 5.0L, and 5.7L Alpha sterndrives within the specified serial number range.
  • Durable Construction: Made from a superior, tension-resistant rubber compound with a strengthened main structure for longevity.
  • Application Specific: Designed for engines with standard cooling systems and a 5-3/4" power steering pulley.

Part Number Cross-Reference

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

Brand Part Number
Mercury / MerCruiser 57-861758
Mercury / MerCruiser 57-861758Q
Mercury / MerCruiser 861758
Mercury / MerCruiser 861758Q
Sierra 18-15116
Recmar RM57-861758Q

Compatible Engine Models

Confirm your engine model/year in the table below.

Brand Model Rated HP Stroke Years OEM Part No. Notes
MerCruiser 4.3L Alpha 190-220 4-Stroke 1996-1999 57-861758Q Serial #OF803000-OL618999
MerCruiser 5.0L Alpha 230-260 4-Stroke 1998-1999 57-861758Q Serial #OL012052-OL618999
MerCruiser 5.7L Alpha 250-300 4-Stroke 1997-1999 57-861758Q Serial #OK001506-OL618999
MerCruiser 350 Mag Alpha 300-350 4-Stroke 1997-2004 57-861758Q Serial #OK001501-OL618999

Technical Specifications

Specification Value
Product Type Serpentine Belt
Installation Engine Accessory Drive
Belt Type Ribbed Serpentine
Belt Length 219.7 cm (86.5")
Belt Width 2.06 cm (0.81")
Material Superior Rubber Compound
Weight 0.56-0.65 lbs (0.25-0.30 kg)
Color Black
Application Standard Cooling with Power Steering
Compatibility 5-3/4" Power Steering Pulley
Other Technical Attributes Tension-resistant with strengthened main structure
Warranty 1 year against manufacturing defects

Package Contents

  • 1 x Serpentine Belt (Replaces 57-861758Q)

Installation Guide

  1. Safety First: Disconnect the boat's battery to prevent accidental starting.
  2. Locate Components: Identify the serpentine belt, tensioner pulley, and all accessory pulleys (alternator, power steering pump, etc.).
  3. Document the Route: Before removing the old belt, take a clear photo or draw a diagram of its routing path. This is critical for correct installation.
  4. Release Tension: Use a properly sized socket or wrench on the automatic tensioner pulley to release the belt's tension.
  5. Remove Old Belt: Carefully slide the old belt off all the pulleys.
  6. Verify the Part: Compare the new belt with the old one to confirm the length and number of ribs are identical.
  7. Route New Belt: Following your diagram, carefully route the new belt around the pulleys, saving the smoothest, most accessible pulley (like the idler or water pump) for last.
  8. Apply Tension: Release the tensioner again and slide the belt over the final pulley. Double-check that all ribs are properly seated in the pulley grooves.
  9. Final Check: Slowly release the tensioner, allowing it to apply pressure to the new belt. Visually inspect the entire belt path one more time.
  10. Test: Reconnect the battery, start the engine, and listen for any unusual noises. Let it run for a minute to ensure the belt tracks correctly.

Troubleshooting & FAQ

How do I confirm this belt fits my MerCruiser engine?
Verify your engine details against the "Compatible Engine Models" table. This belt is specifically for MerCruiser 4.3L, 5.0L, and 5.7L Alpha engines from 1996-1999 falling within serial numbers OF803000-OL618999. It is also critical to confirm your engine uses a standard cooling system and a 5-3/4" power steering pulley, as other configurations will use a different belt.

What are common signs that my serpentine belt needs replacement?
Indicators of a failing belt include visible cracks, fraying, missing ribs, or a glazed, shiny appearance. You may also hear persistent squealing or chirping noises from the engine bay, especially on startup or when turning the steering wheel. Failure of accessories like the alternator or power steering can also point to a broken belt.

How often should I inspect or replace my serpentine belt?
Regular inspection during routine maintenance is recommended. A general guideline for replacement is every 3-5 years or upon visible signs of wear and tear. Always consult your engine's service manual for the manufacturer's specific maintenance schedule.

OEM vs. Aftermarket?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.

We can ship to virtually any address in the world with free shipping available for most regions.

For our typical US and Canadian customers , our shipping timeframes are as follows:

  • Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
  • US warehouse shipment: orders will be delivered within 5 days after placing the order.
  • China warehouse shipment: orders will be delivered about 12 days after placing the order.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.

As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.

We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.

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