ARCO 2005-Up Mercury Outboard Ignition Coil

The ARCO replacement ignition coil is intended for 2005-up Mercury DFI outboards across a broad horsepower range. The supplier also lists 1100, 1350, and 1650 QC4V race sterndrive applications, making this coil useful beyond standard production outboards. Because those engine families use specific electronic ignition hardware, fitment should be confirmed from the engine model or the original coil number. The component is designed as a replacement for the existing coil rather than a universal high-performance conversion.

Mercury 300-8M0077471, 339-879984A1, and 339-879984T00 are listed as OEM interchange numbers. Sierra 18-5159 and CDI Electronics 184-0003 are also included in the supplier cross-reference information. Those references are especially helpful on later engines where several visually similar coils may be used across different control systems. Compare the connector, mounting position, and secondary lead arrangement with the removed part before installation.

Inspect the surrounding ignition harness and plug connection for corrosion, heat damage, or loose terminals while access is available. A new coil should be installed only after confirming the circuit and related components are in serviceable condition. ARCO lists 12-month parts-and-labor warranty protection for this replacement component. Once installed, verify starting and running quality under load instead of relying only on a static spark check.

• Covers multiple Mercury DFI outboard applications
• Also listed for select QC4V race sterndrives
• Cross-references Mercury, Sierra, and CDI Electronics part numbers
• Application-specific electronic ignition replacement

For additional Mercury ignition coils and engine-control service components, Browse more Engine Controls & Ignition for related replacement and service components.