When I bought my 2008, it had sat for couple years. Carbs gummed up and in my attempts to get it running, I hydro-locked engine due to petrol leaking past float-valves and filling engine.
Went to crank and it had slow spin, caught 1-2 puffs, and made scratching noise. Result was 4 broken teeth off ring gear. I managed to find all pieces which had stuck to stator coils. Welded teeth back onto starter gear and it'a been working fine since.
Seems worse damage in your situation with broken cases. Personally I would have no problems welding case back together. But you may have difficulty finding someone qualified to do work. And cost may be prohibitive compared to used set of cases.
Might as well rebuild it in process with new bearings, rings and seals.
