So long as the flywheel is turning, the stator would power the CDI box and the trigger (the arm that moves as you change throttle position) would still fire the CDI. it would all just happen at the wrong time.
Now if the engine is cranking too slowly then maybe not. Remove all 3 spark plugs, shoot some fogging oil in the cylinders & try again with the plugs removed. Maybe the cyljnder walls are all dry & engine is cranking slow.
Max timing (somewhere around 30 degrees BEFORE TDC ) is set with engine running in gear under load (as in with a test prop or driving boat which becomes a 2 person job) at a specified RPM (3000 if I recall). There is no minimum timing specification. Idle speed is adjusted with the idle stop screw while all 3 throttle plates are fully closed. This idle stop screw stops the trigger arm as the timing retards. In other words, idle timing which may be AFTER TDC is what controls idle speed.
This ignition system is self powering. If it is functioning properly, the engine could be 100% disconnected from the boat electrical (battery cables & big red plug), you could rope start it & have no way to shut it off. So, a short to ground, failed key switch or emergency stop lanyard (if installed) could be the problem. 1st & easiest test is disconnect the big red connector & short across the solenoid to ground. If spark now, problem is forward of engine (If this is you, jump to end of answer). If no spark, problem is ignition component.
Do not go out & buy parts because of the following!!!!!
1) OMC most often CDI failure. Can kill 1 or multiple cylinders. Most often fail after sitting over winter.
2) Ignition coil next but will kill only 1 cylinder. Almost unheard of for all to fail simultaneously. If 1 cylinder is dead, swap that coil with one that fires to confirm problem follows.
3) Trigger, senses magnetic pulses from inner hub of flywheel to fire the correct cylinder. Magnets have N & S poles. This is how it knows which cylinder to fire when. Can kill 1 or all cylinders on a 3 cyl engine. I don't believe it can kill 2 of 3 but I may be wrong.
4) Stator, has 2 sets of windings. Yellow wires go to rectier for battery charging only. If yellow side fails engine will run. Other side charges CDI.
5) Flywheel magnets can loose their magnatism, break or depending on design come loose & move. If key shears (typically from improper torque or hard prop impact) timing would be off but spark would be there if tight enough that starter can spin engine.
I did not include the possibility of wire damage under the cowling but it is certainly possible. Your 1st picture where you are pointing appears to show corrosion & mouse **** residue. Take a look at damaged insulation or wires chewed thru.
If after disconnection of red plug you have spark: This is a pontoon. Rodents & particularly muskrats like to sit on top of right pontoon & eat the wire harness running forward. Check it for condition.
