Description
Sierra 18-5186 Mercury Ignition Coil is a premium replacement part designed to maintain a high-performing ignition system for wide-ranging marine outboard engines. It acts as a direct swap-in for a variety of original equipment manufacturer (OEM) part numbers, including popular Mercury, Mariner, and Chrysler Force applications.
Product Compatibility & Specifications
- Engine Fitment: Built primarily for carbureted Mercury and Mariner 2-stroke models ranging from 6 hp up to 140 hp. It also fits Chrysler Force 40–120 hp models (typically mid-1990s ranges) and Sport Jet 120/150 models.
- Interchangeable Parts: Directly replaces Mercury part numbers 339-832757A4, 339-7370A13, 339-7370B13, and 8M0219430.
- Key Traits: It uses a female connector designed for a coil-near-plug mounting style and weighs approximately 6.56 ounces.
Installation Tips
- Sealant Application:Many marine mechanics recommend applying a thin bead of high-temp RTV silicone sealant (such as Permatex Ultra Black) around the outside diameter of the core pegs during assembly. This protects the coil from excessive engine vibration and premature failure. Allow 24 hours to cure before firing up the motor.
- Avoid Over-tightening:When mounting the central through-bolt and screwing the brass terminal terminals snug, use hand tools like a 10mm socket and a 9mm wrench. Excessive torque can easily crack the terminal screws or break the plastic coil housing.
- Dielectric Grease:Always coat the inner brass contact point of your spark plug wires with dielectric grease before clicking them onto the new coil to shield the terminal from corrosive saltwater environments.
