Spark Plug Wire Set – Fits Mercruiser and Volvo Penta 5.0L, 5.7L Sterndrive Motors (Replaces 3888328, 816608Q61)

Spark Plug Wire Set – Fits Mercruiser and Volvo Penta 5.0L, 5.7L Sterndrive Motors (Replaces 3888328, 816608Q61)

This spark plug wire set is compatible with Mercruiser V8 5.0L and 5.7L GM-MPI sterndrive engines featuring Thunderbolt ignition systems. It is also designed for Volvo Penta V8 5.0L and 5.7L GXI, GI, OSI sterndrive engines equipped with flat top distributors.

It serves as a direct replacement for multiple OEM part numbers including Volvo 3888328 and Mercruiser 816608Q61 among others, ensuring fit and function for these marine engines.

• Package contents: 9 spark plug wires of varied lengths
• Fuel type compatibility: Gasoline
• Installation method: Direct fit replacement with plug-in terminal connectors

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 Mercruiser 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.

Confirm your engine model/year in the table below. For Volvo Penta owners, here’s a guide to help you identify your engine’s serial/model: Johnson Serial Number Guide.

Technical Specifications

Package Contents

• 2 x Spark Plug Wire, 89cm/35 inch
• 2 x Spark Plug Wire, 76cm/29.9 inch
• 2 x Spark Plug Wire, 67cm/26.4 inch
• 2 x Spark Plug Wire, 53.5cm/21.1 inch
• 1 x Spark Plug Wire, 35cm/13.8 inch

Installation Guide

1. Identify and disconnect the old spark plug wires from the spark plugs and distributor cap.
2. Compare the lengths of the new wires to the old ones to ensure proper fitment.
3. Route the new wires carefully to avoid contact with hot engine parts or moving components.
4. Attach the wires to the spark plugs by pushing the terminals firmly onto the spark plug terminals.
5. Connect the other ends to the corresponding terminals on the distributor cap, ensuring a secure fit.
6. Check that wires are not crossed or touching each other to prevent misfiring.
7. Double-check all connections for tightness and correct routing.
8. Start the engine and verify smooth operation and proper ignition performance.

Troubleshooting & FAQ

• How do I confirm this fits my engine? Consult the compatible engine models table and verify your engine’s OEM part number and specifications match those listed here.
• How often should I replace spark plug wires? It is generally recommended to inspect and possibly replace spark plug wires every 2-3 years depending on usage and condition.
• Are these spark plug wires identical to OEM? 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.
• What if a wire is too short or doesn’t fit? Some customer reviews note fitment issues with specific models, such as the Volvo Penta 5.0 GXI coil wire being too short. Verify your engine specs before purchasing.
• 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.