Alternator V-Belt – Fits Yanmar 6LY3-Series Marine Engines (Replaces 119578-42360)

Alternator V-Belt – Fits Yanmar 6LY3-Series Marine Engines (Replaces 119578-42360)

This alternator V-belt is designed for a precise fit on Yanmar Marine 6LY3-series (STC, STP, UTC, UTP, ETP) diesel engines. Built to meet or exceed original equipment specifications, it ensures reliable power transmission from the crankshaft to the alternator, keeping your battery charged and essential electronics running smoothly.

This component directly replaces Yanmar part number 119578-42360 and Recmar part number REC119578-42360, offering a dependable and cost-effective alternative to OEM parts.

• Installation Type: Direct OEM replacement
• Fuel Compatibility: Diesel
• Construction: Made from durable, fiber-reinforced rubber for longevity and resistance to heat and oil.

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.

Technical Specifications

Package Contents

• 1 x Alternator Belt (Replaces 119578-42360)
• Important Note: Some engine configurations may require two (2) belts. Please verify your specific requirement before ordering.

Installation Guide

1. Safety First: Turn off the engine and disconnect the battery's negative terminal.
2. Locate the Belt: Identify the alternator and the existing V-belt routing.
3. Release Tension: Loosen the alternator's pivot and adjusting bolts to release the tension on the old belt.
4. Remove Old Belt: Carefully slide the old belt off the alternator and crankshaft pulleys.
5. Install New Belt: Route the new belt onto the pulleys, ensuring it is seated correctly in the grooves.
6. Apply Tension: Use a pry bar or tensioning tool to apply appropriate tension to the belt while tightening the adjusting bolt. The belt should have about a half-inch of deflection when pressed firmly.
7. Tighten Bolts: Securely tighten the alternator's pivot and adjusting bolts.
8. Final Check: Reconnect the battery, start the engine, and check for proper belt operation and listen for any unusual noises.

Troubleshooting & FAQ

How do I confirm this belt fits my Yanmar engine?

This belt is specifically for the Yanmar 6LY3-series diesel engines. To ensure a perfect match, please compare your existing belt's part number to 119578-42360 and check your engine model against the compatibility list provided above.

How many belts do I need for my engine?

This package contains one (1) alternator belt. While many configurations use a single belt, certain Yanmar 6LY3 models may require two. We strongly recommend checking your engine's specific setup before purchasing.

What are the signs my alternator belt needs replacing?

Common symptoms of a failing belt include a loud squealing or chirping sound from the engine, visible cracks or fraying on the belt's surface, or a battery that fails to hold a charge due to the alternator not spinning correctly.

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.