ARCO Marine Premium Replacement Ignition Coil f/Mercury Inboard Engines (Early Style Volvo)

The ARCO Marine Premium Replacement Ignition Coil for Mercury Inboard Engines (Early Style Volvo) is a direct-fit OEM-equivalent component designed for reliable engine starting and consistent spark delivery on early Volvo 8.1-liter inboard platforms. This ignition coil replaces Mercury part numbers 300-8M0187403 and 881732, as well as Sierra's 18-7648, making it a verified solution for boaters needing dependable electrical system components without premium aftermarket pricing.

Ignition coil performance directly impacts engine reliability in marine environments where salt air and vibration accelerate electrical component wear. This replacement unit maintains proper voltage delivery to spark plugs across the full operating RPM range, preventing the misfires and hard-start conditions that plague aging ignition systems. The coil's compact 4 x 2 x 4 inch form factor allows straightforward installation in tight engine bay spaces typical of inboard mercury installations. Built to handle the thermal cycling and humidity exposure inherent to marine duty, this component resists corrosion better than older OEM coils that may have degraded from years of exposure.

This replacement is essential for inboard boat owners running Volvo 8.1L, 8.1GI, 8.1GSI, or 8.1GXI engines who experience rough idle, starting hesitation, or fuel economy loss—all classic signs of failing ignition coils. Weekend fishermen and offshore anglers alike depend on engine systems that fire on demand; a worn coil can leave you stranded miles from the dock. The ARCO Assurance warranty provides 12 months of parts and labor protection, giving you confidence in this mission-critical component.