Yes, you can use the mag off another, similar, same manufacturer engine. Use a guvment style post card to reset the flywheel gap. Sand the rust off the flywheel legs and the magnet on the flywheel. I think when you get the flywheel exposed, you will find that the meece have eaten the insulation off the coil to plug wire. A common occurence on machinery that has been setting idle!
I have one customer whose pet mice have eaten the pink insulation out of his shed, and stuffed it into every engine flywheel housing he has.
And, heck, 64 ain't old!! Try 85! And i'm still fixing all kinds of stuff! And, looking forward to a better year, next year!
Oh, here's a tip: If you find evidence of mousies living free in your engines, try stuffing a dryer sheet, like the Mrs. uses in her clothes dryer, the stinky kind, and stuff ot tape them around your engines. They hate the smell and will move on soon!

Many thanks, rustyj14. The mag wire is OK so I'll set about trying to scavange a mag from a relic in a boneyard somewhere. As far as age goes, I never have felt 'old' until last year (age 57) on the way into the woods for first day of whitetail season I became very out of breath. Short story, I'm nursing severe congestive heart failure of unknown cause. Other issues set it... Still, as far as I'm concerned I have this day and I will use it with gusto!
Blessings, buddy!
Chiz

You might want to check underneath flywheel. 12+ might have points. breaker ignition. Also check that kill wire and make sure it's not grounded.

MY 34 year old tiller wouldn't start after leaving it out for some time. It also had no spark. I changed the condenser and points and it started right up. That's the first place I would look if it has points?????