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[Scalyback]

Sorry, coffee not reacted with me yet. got confused when you said about widening the gap, assumed spark plug connected. But this can replace the plug for testing so set it to a gap twice as wide as atmosphere = 1?



or you could have plug in series and get both sparks with smaller gap in tester! OK, I think I am waking up now.

Very neat job and also reminds me of a soldering iron plug from the telephone exchange!

[Dennis C]

That looks like a well made and useful tool Pete.

j
Just for information the maximum test gap on a magneto should be 6mm any more can cause internal sparking, also some coil/electronic systems can be damaged by bigger spark gaps.

[Scalyback]

OOPS, hope that didn't sound rude, but it does look like them. I'll post one!

[p]

Similar items, with a fixed gap and enclosed in plastic, used to be sold as "spark intensifiers" ... I think there was some scientific explanation (maybe flawed!) which tempted their purchase. Also some plugs also used to incorporate something similar; anyone shed any light on the theory?
By the way, I have an old piezo spark generator from some long departed gas appliance which I use to test spark plugs themselves!

[apparently lucky eddie]

Great idea. But lets be honest guys, not nearly so much fun as getting an idiot to stick a finger in the plug cap

[PeteF]

Didn't know that Dennis, thanks.
I do know that making a coil system jump a big gap does put a strain on the system so not a good idea for a long time.,
Anyway, it did the job this afternoon on the lawnmower. I tracked the fault to an intermittent fault on the earth wire. It was very useful to be able to see if a spark was there or not without all that fiddling about earthing the plug.

[PeteF]

Oh, and the little ignition coil on the mower (flywheel magneto?) Jumped an 8mm gap no problem as long as the cranking speed was brisk enough.