Hi, I found an old OS 60 SR engine that is locked solid due to old fuel being left in the engine. I am sure I can clean the engine and get the beast running again. My question is - One of the muffler mounting bolts in the crankcase is broken. Can I purchase a new crankcase for this engine and if so, do I purchase a crankcase for an FSR or what. Anyone know thehistory of the SR engine line? I can't find anything on the internet about this engine.