RANSOTO Ignition Coil Pack for Mercury/Mariner Outboards — 2-Pc 6–150HP Replacement, OEM Match 18-5186

RANSOTO 18-5186 ignition coil pack (2 pcs) is a direct-fit replacement designed to restore reliable spark for compatible Mercury, Mariner and Chrysler Force outboard motors from 6–150HP.

If your outboard is misfiring, hard to start, or running unevenly, a failing ignition coil can be the cause. These RANSOTO coil packs match common OEM part numbers (18-5186, 339-7370A13, 339-832757A4/B4) and are offered as a two-piece set so you can replace both coils at once. They are manufactured to fit a wide range of Mercury & Mariner models as well as specific Chrysler Force engines, making them a practical spare for boat owners, marinas, and repair shops.

Which engines and years will these coils fit?

These coils are engineered to be compatible with many Mercury and Mariner outboard models spanning small tiller motors to larger V-model engines, plus selected Chrysler Force models from the late 1980s through mid-1990s. Always cross-check your engine model and OEM part number before ordering to confirm fit.

• Mercury/Mariner: compatible across 6–125HP, 140HP, V135, V150, 210CC ranges.
• Supported HP list: 6, 8, 9.9, 15, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70, 75, 80, 90, 100, 115, 125, 140.
• Chrysler Force coverage: 40–150HP models (specific years 1989–1995 depending on HP).
• Replaces OEM numbers: 18-5186, 339-7370A13, 339-832757A4/B4.

How do these replacement coils improve engine performance?

New ignition coils supply a consistent high-voltage pulse to each spark plug, which helps the engine ignite fuel cleanly and run smoothly. Replacing worn or cracked coils reduces misfires, improves throttle response, and can make cold starts easier.

• Restores consistent sparking across cylinders for smoother idle and acceleration.
• Reduces sputtering and intermittent power loss caused by weak coils.
• Two-coil package lets you service both coils at once for balanced ignition.
• Matches common OEM specifications for straightforward installation.

What should I know about installation and compatibility checks?

Installation is typically a straightforward bolt-and-plug swap on compatible outboards, but follow your engine’s service manual for torque values and wiring checks. If you are unsure, consult a marine technician; improper installation or incorrect gap/wiring can cause performance issues.

• Inspect wiring harness, boots, and mounting surfaces before fitting new coils.
• Compare the OEM part number printed on your old coil to ensure correct match.
• Secure mounting and clean contact surfaces improve longevity and performance.
• Check all spark plug wires and connectors while replacing coils.

Who is this for? The RANSOTO 18-5186 two-pack is intended for boat owners, mechanics, and service shops maintaining Mercury, Mariner, and Chrysler Force outboards that use the listed OEM part numbers. It suits anyone needing an affordable, ready-to-install coil replacement to address ignition faults, misfires, or preventative maintenance. RANSOTO backs the product with a one-year satisfaction warranty—contact the seller directly if you encounter fitment or performance concerns.