Quote:
Originally Posted by Chris Simenstad
Neil: I have not calculated the ignition system current--I switched to electronic ignition in 2008. What would be the reason too? Not enough current= weak spark?
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The issue with EI and current is there's a maximum, a not to exceed value of 4 amps. Anything above 4 amps and you risk overheating the coil, damaging the internal windings and repeated engine shut downs. Our recommendation is to build in a 15% margin of safety for a max current of 3.4 amps.
For example let's say you have electronic ignition and a coil that measures 3Ω. You know that the engine operates on a 12 volt system so all seems good (12V÷3Ω=4.0 amps). Not so fast. When the engine is running the alternator determines the voltage, usually around 14.2 volts so in reality your amperage is more like 4.7 amps. Oh-oh, trouble ahead. The example doesn't take into account wiring voltage drop but that's supposed to be less than 3% which affects the result by only 1/10th of 1 amp.
If you're above 4 amps, coil failure doesn't happen instantly. It builds up over time and the internal coil damage is cumulative.