Looks to me like an old Tecumseh or Briggs. How about a couple more pics of the other sides? Carefully scrap the top of the shroud, by the loop, I’ll bet you find some numbers.
1964 or 1974 or 1984 can’t get any closer than that. I’ll contact a member over there and see it he can help you get parts. Have no idea about the mower.
On the older Tecumseh engines, with 5 characters, the first number is the year of manufacture. His is 4, but that is as close as Tecumseh goes, which is why I gave three different years.