Tap Spark Ignition

[Richard Durgee]

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This is a 1904 Marine engine ad, it mentions jump or tap spark, is anyone familiar with the term "Tap Spark" ?

[Andrew Mackey]

Both terms, jump spark and tap spark, are archaic terms for ignition systems. Jump spark refers to spark plug ignition. The spark has to 'jump' a gap in the plug, thence the name. Tap spark refers to ignitor ignition. Usually, on the marine engines, the ignitor is tapped by the trip mechanism, and it was usually battery and coil for power. Marine engines, like aircraft engines and fire equipment, often had 2 seperate ignition systems, that operated independantly from each other. At the time, magnetos were often not that reliable, or powerful enough to start the engine in cold or damp weather. A battery and coil was often used to start the engine, and then it was switched to magneto for running. If the mag quit, the battery and coil would get you home.
Andrew

[Richard Durgee]

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Thanks Andrew,

I thought that "Tap Spark" was probably a local, casual or nonformal reference to mechanical or make and break ignition but I have never heard it used or seen it in print anywhere other than the ad in above post ?

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