Spark plug gap/voltage

[rodbolt17]

and that is why most Yamaha COP systems use a Zener diode. if it sparks at all it starts at 32 Kv. and yes my Kv tester reads the peak.

[boscoe99]

COP = Coil On Plug for those that don't know.

A great system IMO. Maybe it is just me coming from the old days of points and plugs however. Plugs that were eaten up in 3000 miles. Points that needed to be adjusted often. What a pain.

Nothing like being in the open ocean with a motor that ran on points and plugs. Wondering if the damn thing would ever start. No radios on board to call anyone. No paddle of course. That was what testosterone was about I suppose. Too stupid to know any better.

Of course back in the day it was ever so much easier getting to parts on the motor than it is today. Particularly on an automobile.

[99yam40]

I was never stranded with the old points and condenser system, you could always make it go for a little longer before it burned the points again.

but the new stuff caused me a problem when the Mass air flow went bad and just dumped way too much fuel.
had to pull the plugs and spin it over to clear the cylinders.
got it fired up and headed to a shop.
had no idea what was going on

[panasonic]

I was wondering when aviationman would be along. Tell us a bit about gas turbine igniters and such. And joules. It is one thing to ignite gasoline. Something altogether different to ignite Jet A at 35,000 feet.

Keep your fingers away from them testing....

They are rated in Joules, which is basically a measure of amount of work done...

wiki says It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule

Very simple system CDI ignition, no timing involved so just snap,snap,snap..when turned on. But I think they produce a very different spark then a typical CDI that we would think about. It just stays at constant amount of discharge's per second.

But more to it then meets eye for us simple men...read this if you dare lol http://worldphaco.com/uploads/GAS_TU...R_EXCITERS.pdf

They are automatic during start up, turn on manually during take off, landing, heavy rain, ect. They are off most of the time the engine is running.

Plugs don't last that long and are changed frequently, they erode away quite quickly.

Very reliable system, don't remember ever changing a ignitor box. The leads go bad where they attach to the plug sometimes.

https://www.youtube.com/watch?v=NmHW65093_o

[ausnoelm]

The voltage produced is not dependant on plug gap, the same voltage jumps a smaller set plug as it does on a wider set plug, the ignition produces plenty to jump the gap if it's too big, the ignition system does not know if you just fiddled with the plug gap, it just sends KV down the lead, the gap can however cause some issues if set incorrectly, in an experimental lab, voltage could be increased slowly until the spark jumped the gap, and this could be altered to make the voltage required be higher, but that does not happen in "electronic" ignition, it produces max voltage in an instant and consistently, regardless of plug gap.