Re: battery ignition vs. alternator ignition
Silvertip, While what you have stated about battery-driven ignitions having distributors is correct, that was a design decision, based upon cost, not physics. Merc built their battery-driven cdi ignition systems with a distributor and a single switchbox. They could have easily built a battery driven CDI system with seperate coils, triggers and switchboxes, and not used a distributor. Also, on the battery-driven CDI systems, Merc used a stator and a rectifier to change the battery. Battery charging was completely seperate from the ignition, however, the source of the battery charging voltage and current came from the stator under the flywheel and the flywheel's permanent magnets.
The newer Outboard ignition systems use a combo stator that supplies voltage to run the ignition system switchboxes or power packs, as well as charge the batteries via rectifier or voltage regulator. At least one outboard that I know of has an external automotive-like belt driven alternator, but the vast majority use stators for both purposes. Also, my '98 150HP Johnny uses battery voltage to supplement the stator voltage to the powerpacks during starter cranking. After the motor starts. only the stator powers the ignition system.