Ignition Coil Optimax | CDI 184-0004 CDI Electronics Ignition Coil Optimax | 184-0004 Ignition coil used on a variety of Mercury Optimax DFI V6 outboards. Mercury Optimax ignition coil Used on 2005 and Up 135, 150, 175, 200, 225 and 250HP DFI Outboards Used on Mercruiser 1100,1350 and 1650 QC4V Race sterndrive engines Replaces Mercury 339-8M0077473 Replaces Sierra-18-5159 CDI Electronics: Keeping Your Boat and Engine Running Smooth CDI Electronics has been in the business of keeping boats and other engine-powered machines happy and healthy for over 35 years! They specialize in making ignition systems and tools to help diagnose problems so your engine runs its best. They even train technicians on how to install and fix these parts. From Fixing to Making: CDI started in 1982 as a repair shop called Rapair Incorporated. They fixed boat engine ignitions out of a small garage in Alabama. They learned a lot about what went wrong with these systems, and in 1995, they decided to put that knowledge to good use! They started designing and building their own ignition parts under the CDI Electronics brand. These parts were known for being reliable and affordable compared to what came with the engine originally. New Owners, Bigger Dreams: In 2007, CDI was bought by new owners who brought fresh ideas and experience in the marine industry. They helped CDI run their business better and sell their products all over the world. In 2014, CDI even got a special certification that shows they make high-quality products. They also bought a company called Balmar to start making parts for charging systems on boats with inboard engines. Today, CDI Electronics is all about providing value and the best possible parts for your boat or engine. They want to keep you on the water and enjoying the ride! Shop today for CDI Electronics to keep your marine engine running at peak performance!