V-Belt – Fits MerCruiser 5.0L, 5.7L, 7.4L, 8.2L Engines (Replaces 57-48122Q)

V-Belt – Fits MerCruiser 5.0L, 5.7L, 7.4L, 8.2L Engines (Replaces 57-48122Q)

This engine V-belt is engineered for reliable performance in MerCruiser V8 engines (5.0L, 5.7L, 7.4L, 8.2L) manufactured from 1988 to 2001, including Bravo and MIE models. It also fits a wide range of OMC sterndrive engines.

It serves as a direct replacement for Mercury/Quicksilver part numbers 57-48122Q, 48122, and 48122Q, as well as aftermarket equivalents from Sierra and GLM. This belt drives the alternator and water pump on engines with V-belt systems.

• Designed as a direct OEM-equivalent replacement for alternator and water pump drives.
• Constructed from durable rubber with a reinforced fiber core for enhanced longevity and grip.
• Compatible with both raw water and fresh water cooling systems.

Part Number Cross-Reference

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

Compatible Engine Models

MerCruiser 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.

OMC Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x V-Belt (Replaces 57-48122Q, 48122, 48122Q, 0509295)

Installation Guide

1. Ensure the engine is turned off, has cooled completely, and the battery is disconnected.
2. Loosen the alternator pivot bolt and any corresponding adjuster-plate or tensioner bolts.
3. Carefully note the belt's path around the crankshaft, water pump, and alternator pulleys.
4. Remove the old belt by swiveling the alternator inward to relieve all tension.
5. Before installing the new belt, inspect all pulley grooves for excessive wear, rust, or damage.
6. Route the new belt following the same path as the original.
7. Tension the new belt by carefully swiveling the alternator away from the engine.
8. A correctly tensioned V-belt should deflect about 1 cm (½″) under moderate thumb pressure at its longest span.
9. Securely tighten all pivot and adjuster bolts to the manufacturer's recommended torque specifications.
10. Reconnect the battery.
11. Start the engine and carefully observe the belt to ensure it is tracking properly in the pulley grooves.
12. After a brief run time, shut down the engine and recheck the belt tension, adjusting if necessary.

Troubleshooting & FAQ

How do I confirm this V-belt fits my specific MerCruiser or OMC engine?
Verify your engine model and year against the compatibility tables on this page. It's critical to also check the OEM part number (such as 57-48122Q or 0509295) printed on your old belt or listed in your service manual. This is a 48-inch V-belt, not a serpentine belt, so ensure your engine uses this type.

What are the common signs that my V-belt needs replacement?
Common signs of a failing V-belt include visible cracks, fraying, or a glazed, shiny appearance on the belt's surface. You might also hear a high-pitched squealing sound during startup or acceleration, or notice your battery isn't charging properly due to alternator slip.

How often should I replace my engine's V-belt?
While a universal replacement interval doesn't exist, it is best practice to inspect your V-belt during every routine service check. We recommend replacing it proactively every few seasons or immediately if you notice any signs of wear, damage, or loss of tension to prevent unexpected failure on the water.

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.