Crowsbeak , here are the Time Serts that I use. I got them from Amazon. It may possibly be overkill, but I use them all the time in my cars and other outboards, and have never had a problem yet with one of them pulling out. Super strong. Large initial investment at first, but after you buy the kit the extra Time Serts aren’t that costly.
You might want to go the route that Dave B suggests, or Helicoils. Just remember that the screw thread is a 10-24.
Good luck, this is certainly not one of the fun aspects of outboard restoration. I will post some pictures of the completed Time Serts in place, if there is any interest .
Bob D
