WOW !!!!!!
That's absolutely unbelievable !!!
How can someone let a piece of machinery go so bad ??
If I'm correct that is a H25 engine on what would be quite a rare Scotty as it's got both a brass and ally plate riveted to the chassis rail. There weren't many of that combination made.
Honestly I would just find another Kirby engine and fit it, unless you specifically want the original one to fly again.
Cheers,
BB.