This is off of my A-45 Johnson. The wires on this one come off the bottom, but
I assume you have a similar magneto plate with a single, dual secondary coil.
If your coil test okay with an ohm meter, then I’d go ahead and use it.
Care is required installing new plug wires so the “hair” thin windings in the coil, under
the plug wire doesn’t overheat.
If the coil is bad, there may be options of a coil swap. Search the forums, should be
lots of examples.
Prepare to be boarded!