V-Belt – Fits Volvo Penta AQ271, AQ311 & 5.7L V8 350 Engines (978750, 966857)

V-Belt – Fits Volvo Penta AQ271, AQ311 & 5.7L V8 350 Engines (978750, 966857)

This is a high-quality aftermarket alternator V-belt designed for a wide range of Volvo Penta marine engines. It is engineered to fit various 4-stroke models, including the AQ271 and AQ311 series, as well as multiple 5.7L V8 350 models manufactured from the 1970s through the 1990s.

This V-belt serves as a direct replacement for Volvo Penta part numbers 978750, 966857, 22298172, and 20405712, along with Sierra Marine part 18-4046, ensuring broad compatibility and reliable performance.

• Application: Designed for use with 50 amp alternators.
• Durable Construction: Made from heat and grease-resistant rubber with high-strength synthetic cords for long service life.
• Package Includes: 1 x Alternator V-Belt.

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 V-Belt (Replaces 978750 / 966857)

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning any work.
2. Locate the Belt: Identify the alternator and the V-belt path around the pulleys.
3. Release Tension: Loosen the bolt on the alternator or tensioner pulley to create slack in the old belt.
4. Remove Old Belt: Carefully slide the old V-belt off all pulleys.
5. Inspect Pulleys: Check the pulleys for any signs of wear, damage, or misalignment. Clean them if necessary.
6. Route New Belt: Following the engine's belt-routing diagram, install the new V-belt onto the pulleys.
7. Apply Tension: Adjust the alternator or tensioner to apply the correct tension to the new belt. A rule of thumb is about half an inch of deflection with firm thumb pressure.
8. Tighten Bolts: Securely tighten all bolts that were loosened.
9. Final Check: Reconnect the battery, start the engine, and listen for any unusual noises. Ensure the belt is running smoothly.

Troubleshooting & FAQ

Q: How do I confirm this V-belt fits my Volvo Penta engine?
A: Please check the 'Compatible Engine Models' and 'Part Number Cross-Reference' tables on this page. Match your engine model or original part number (e.g., 978750, 966857) to ensure an exact fit.

Q: What are the signs of a failing V-belt?
A: Common signs include high-pitched squealing noises from the engine bay, visible cracks or fraying on the belt, a hard or glazed appearance, or a battery warning light on your dashboard, which may indicate the alternator is not being driven properly.

Q: How often should I replace my engine's V-belt?
A: While there is no universal interval, V-belts are typically inspected during routine maintenance and replaced every 3-5 years or as recommended by your engine's service manual. Replace it immediately if you notice any signs of wear or damage.

Q: OEM vs. Aftermarket?
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.