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Johnson Outboard Coils

Written by Nicholas Kamuda
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Replacing the Johnson outboard coils on your engine can be simple if you follow the proper procedures. The coils, part of the engine's ignition system, can be found along the path of the wires that connect the ignition switch to the distributor, power packs, and spark plugs. By following the procedures documented in Johnson service manuals, replacing old or damaged Johnson outboard coils can be a quick and painless process.

The coils' main function is to amplify the signal that is generated by the battery upon startup. When you turn the key in the ignition switch of your Johnson engine, an electrical signal is sent to the Johnson outboard coils, which is stored and amplified in the coils. Once the signal is strong enough, the electricity is sent to the distributor, which will activate the spark plugs at the correct time and in the correct order, causing the pistons to move in the cylinders.

Testing Johnson Outboard Coils

If your engine doesn't seem to be receiving any spark, there may be a problem with the amplifier coils. A good first step is to double-check the wires and contacts for corrosion or wear. If everything appears to be clean and functional, simply touch a voltmeter to the positive terminal of the coil (usually the one with a purple wire) to test the coil. As long as there is a the correct charge moving across the coil (as specified in the service manual), then the problem most likely lies elsewhere in the ignition system.

If there is no charge at the positive terminal of the coil, then the coil may be damaged. Replacement coils can be purchased at many marine parts supply stores and from boating supply websites. Many online parts vendors offer fast shipping and knowledgeable sales staff to help you get your boat back in the water as quickly as possible.

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