ARCO Mercury 1998-2006 Replacement Ignition Coil

The ARCO ignition coil is an application-specific replacement built to restore dependable spark energy on the compatible outboard engines listed for this part. This ignition coil fits 1998-2006 (135,200,225,250 & 300HP) Mercury outboard engines. Replaces: MERCURY Ignition Coil 339-850227 MERCURY Ignition Coil 339-856991A1 SIERRA Ignition Coil 18-5187 CDI Electronics Ignition Coil 184-0005 Matching the coil to the exact engine family and production range is essential because ignition connectors, mounting, and electrical characteristics can vary between otherwise similar engines.

A replacement ignition coil converts the ignition system's low-voltage input into the high-voltage pulse needed at the spark plug. Using the specified ARCO component gives a service-focused alternative when diagnosing a failed or weak original coil, while the listed original-equipment and aftermarket cross-references help confirm the intended application.

Verify engine manufacturer, horsepower, model, year, connector style, mounting arrangement, and applicable replacement part numbers before installation. Disconnect battery power as required by the engine service procedure, keep ignition connections clean and secure, and route leads away from heat or abrasion. After installation, test engine starting and running performance according to the manufacturer's diagnostic procedure.

• The coil supplies the high-voltage pulse required for compatible spark-plug ignition.
• Engine and replacement-number references help confirm correct fitment.
• Application-specific service parts support targeted ignition repair.
• Correct installation and clean terminals help preserve ignition performance.

See what else we carry in engine controls & ignition.