Re: How do Atom Computer Ignition modules work?

[John]

quote legendre:

quote jnjvan:

The chances are excellent. You turn the mag plate to get the peak (and the points opening) at the correct crankshaft timing angle.

JV

Only one of those events can be precisely set. You either time for optimal spark energy, or you time for the most efficient crank angle – you can’t have both.

Fortunately, the former has a fair amount of angular ‘slop’ – the latter, not so much.

But you can have both: You time for optimal spark energy with the points, you time for crank angle by rotating the magneto plate (which moves the coil and the points relative to the crankcase). The points gap will have a small effect on timing vs the crank, but not much. By far the dominant factor for crank angle timing is the mag control lever.

Your statement is true for lawnmower engines, and others with fixed ignition timing, but not for 99.9% of outboards. The spark control on outboards is very similar to the accessory mag you mention in another post.

I do agree with you that the former has some slop. That’s why you still have spark if you set the gap a few thou either side of the recommended .020 setting.

John Van