Magneto on 1942 John Deere B isn't getting oil, any tips how to fix it?

Everything else in our governor is is getting oil except the magneto. We have it off of the governor case and are trying to figure out what could be the problem. Could someone help?Magneto on 1942 John Deere B isn't getting oil, any tips how to fix it?
Ok I'm gonna try, but it's 3 years older than me lol. Most old mag and govenor drives get ';splash'; oil off the cam gear. Can you see far enough in to figure if maybe a gasket piece is in the way. If it's not something like that, I'd look for a piece of goop blocking a hole, which maybe you could move with an airline blower with a long nozzle. Hope this helps, as it's an old girl, glad it's still going