Re: 1958 Johnson repair help
Howdy, Wes.
Welcome to iboats.
That engine uses a double magneto. The only things the mags share are the points cam and the flywheel, and maybe a kill circuit (depends on model).
Pull the flywheel and inspect the points and the condensers. Check each set of points to ensure that they are not grounded when the points are open.
Without history on the engine or the problem it is very hard to say more.
The coils on those engines are notorious for not lasting much more than 50 years, but they usually don't both croak at the same time.
Tell us more about the engine's history and when you first noticed the problem.
It would be nice if we knew the model number, too.