There are two ignition coils mounted on the magneto plate under the flywheel. two sets of points and 2 condensors. If you see the coils are cracked (at all) replace them both along with the points and condensors.
Hope this is helpful.
SIncerely,
Evinrude-tech
A spark tester will tell you if you have cranking spark while pulling the recoil or keying the electric starter. However it wont tell you if you are loosing spark once the coils get hot which is when a crack would get even larger and arc to the mag plate.
You can use a timing light while the engine is running to see if you have goos steady spark on each cyl while the problem is occuring. This is a more accurate test.
In response to your question about the flywheel. Yes it is alot stronger than it appears. The weak point is the (3) 5/16 holes you hold the puller to the flywheel with. Make sure they are good grade bolts and tighten them securely before trying again.
Good luck!
Marine Mechanic
Evinrude Master Technician with 27 years of experience.
You're welcome. And thank you for the comment!