After a catastrophic failure like that, my advice is to find another engine. To me it would be more dependable than repairing that one. The only thing you need on a different engine is the PTO crankshaft side needs to be tapered and have a threaded hole for the generator bolt. You will see engines with a shaft which have a longer round shaft with a flat side on them but if it has a bolt in it, that shaft comes off the tapered shaft you want. There's one on epay now but the guy wants like $199 for it. Nice engine but you can find one less expensive or buy that one and sell the extra parts. That gas tank alone might sell for $25 - $40 depending on bad someone wants it.
https://www.ebay.com/itm/Vintage-O-R-Ohlsson-Rice-Compact-Engine-w-Gas-Tank/323901552141?hash=item4b6a09760d:g:dN4AAOSwMH9dbAsu
Look at the shaft, remove that bolt and that shaft extension comes off the tapered crank end like you need for attaching a TT generator head.
If you search Orline on there, there are a couple of rods and bearings which might fit your engine but David @factory can help you with what fits better than I can.
You'll probably need a new piston and head, all the gaskets and seals, rod and bearings. By the time you pay for all of that you could probably find a donor engine, change the diaphragm and be up and running for the same amount or less. Plus not worry about if that case piston head and other parts are any good,. Just my opinion. Once you tear it down and have a good look see inside you can make a decision on the best approach. I might have the parts you need to do it.
