ARCO Mercury V8 Delco HEI Marine Ignition Coil

The ARCO replacement ignition coil is made for Mercury V8 inboard engines using Delco HEI ignition. The supplier specifically excludes MPI applications equipped with ECM 555, so identifying the ignition system is essential before ordering. It is intended as a direct replacement for the conventional Delco HEI-style coil used on the covered engines. That application-specific distinction helps prevent using the correct-looking coil on an incompatible electronic ignition package.

Mercury 806673T1, 806673, and 806673T are listed as replacement numbers for this coil. Sierra also cross-references the application under 806673T. Matching one of those numbers to the existing part provides a straightforward confirmation when the engine’s ignition configuration is uncertain. The mounting and electrical connections should be compared with the removed coil before final installation.

While the coil is removed, inspect the cap, rotor, high-tension lead, primary wiring, and grounds for heat damage or corrosion that could contribute to the same symptoms. Replacing a coil will not correct a poor connection elsewhere in the HEI system. ARCO lists 12-month parts-and-labor warranty protection for this component. After installation, confirm consistent starting and ignition performance through the normal operating range.

• Designed for Mercury V8 engines with Delco HEI ignition
• Not specified for MPI engines using ECM 555
• Replaces Mercury 806673-series coil numbers
• Direct marine ignition-system service replacement

For other Mercury inboard ignition components and service parts, Browse more Engine Controls & Ignition for related replacement and service components.