I used to believe that was the case. Below are comments from a member that has passed. Frank tried to dumb it down for people like me so I could understand it, but I still don’t get it.  Maybe you will be able to. 

There are a lot of things happening every time it produces a spark, and it is hard to explain it all in terms understandable to a novice. In fact, I get some more grey hairs every time I think about it. And I have a diploma that says I am a TV repairman (Not). But to share a grey hair, when the magneto points open, electrons flow into the capacitor and the voltage across the capacitor increases with time It is mighty fast, but not instant. When the time is up, the electrons flow back out in the opposite direction in series with the coil. It is that reversal in direction that induces a spark voltage in the secondary winding. A way too big (mfd) capacitor will not charge up to as high a voltage in the time available as would a small capacitor. Also, a leaky capacitor loses energy through the leak just as a leaky bucket takes longer to fill with water.

As I tried to say, the capacitor charges up in one direction, then discharges in the opposite direction, in series with the coil. Several factors combine to affect the voltage that it charges up to. A higher charge voltage in series with the coil voltage creates a higher reverse current through the coil, which results in a higher AVAILABLE spark voltage. AVAILABLE emphasized because the actual spark voltage only rises till it jumps the plug gap. Then it’s all over till next time. In other words, the actual spark voltage is rarely the maximum it can produce. BUT if it it cannot produce enough to jump the gap reliably, you get no-start, hard start, missing, etc etc.

Even though the timer points are normally open, as I read Franks explanation, both would be the same as far as making a spark.  Battery charges the condenser when the points close. Energy is released when the points open. Anybody?

reading up m.Mohat articles on the magic of magneto and phase maker ignition may shed some light.

Magazine Articles | Western Reserve Chapter

Phase maker ignition ( like one version of Mercs)  fires by “MAKING” the points close   so a storage capacitor that was previously charged up   is allowed to suddenly dumps  into the coil to fire it.

Conventional OMC  type ignition allows  the  primary coil  and lamintes to load up  like an electromagnet by induce current  from the  effect of magnetism  passing by the laminates (just like a pedal bike  magneto)

but when points OPEN…

the coil tries to mainting itself magnetized but can’t because it has lost the ground referrence  due to  the  points gap.

The collapse  of the magnetized field  induces a reverse voltage (counter EMF)  which tends to rejoin ground  via the points   but ends up in the condenser which is there to protect the points from excess arcs  that burn the surfaces.

At the same time,  the collapsing primary current using the condensers as a storage bin…. induces a voltage in the secondary winding (with  100-200 times the winding loops ) and it also is looking  for a ground and  finds one  by jumping the sparkplug gap. !

SO.. one system  dumps a load of electrons previously  created and stored   like gunpowder  while the OMC  method  dumps electrons  “created”   on the spot by magnetism collapsing.

my understanding anyway .. somebody surely has something else in mind  🙂