Mercruiser Spark Plug Wire Set - Fits 5.0L, 5.7L & 6.2L MPI V8 Engines (Replaces 84-863656A1)

Mercruiser Spark Plug Wire Set - Fits 5.0L, 5.7L & 6.2L MPI V8 Engines

This spark plug wire set is designed for V-8 MerCruiser stern drive and inboard engines equipped with the ECM 555 electronic control module. It is a direct-fit replacement for 5.0L, 5.7L, and 6.2L MPI engines with serial numbers ranging from 0M300000 through 2A455878.

This kit is a direct replacement for multiple OEM and aftermarket part numbers, ensuring wide compatibility with specified engines. It is designed to meet or exceed original equipment specifications for reliable performance.

• Installation Type: Direct replacement for a hassle-free installation.
• Ignition System: Specifically designed for the Delco HVS ignition system with a flat cap style connection.
• Quality Construction: Features a durable silicone and Kevlar core for maximum protection and performance.

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 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.

Technical Specifications

Package Contents

• 1 x Spark Plug Wire Set (84-863656A1)

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning work.
2. One by One: To avoid incorrect firing order, remove and replace only one spark plug wire at a time. Note the routing of the original wire.
3. Distributor Cap End: Firmly press the new wire's boot onto the correct terminal of the distributor cap until you feel it click into place.
4. Spark Plug End: Route the new wire to the corresponding spark plug and press the boot securely over the plug terminal.
5. Repeat: Continue this process for all remaining wires.
6. Final Check: Once all wires are replaced, ensure they are neatly routed and clear of hot or moving engine parts. Reconnect the battery and test the engine.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: The most reliable way is to check your engine's serial number. This part fits MerCruiser 5.0L, 5.7L, and 6.2L MPI engines with serial numbers from 0M300000 to 2A455878. You can also compare your existing part number to the cross-reference list provided.

Q: What are common signs that my spark plug wires need replacing?
A: Symptoms of failing spark plug wires include engine misfires, a rough idle, poor acceleration, reduced fuel economy, and visible signs of wear, such as cracking or burning on the wire boots or insulation.

Q: How does this aftermarket set compare to the original OEM part?
A: This part is manufactured to meet or exceed original OEM specifications. It uses a high-quality silicone and Kevlar core for excellent heat resistance and durability, ensuring reliable spark delivery.

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.