governor issue?

After a long day of rough cutting, my old Craftsman 19hp I/C gold twin lawn tractor made a "freaky" noise and then started "screaming" with the engine at beyond full blast. I tried to lower the throttle, and idle the engine, but nothing worked. After turning it off, I was able to restart, but it still screams and feels like it is going to blow apart. Now, it turns over, but doesn't start. Probably not a good idea to restart it anyway if is what I think it may be (based on very limited knowledge, a bit of common sense, and a bit of research). Does this sound like a governor gear inside the engine coming apart? If so, what kind of repair bill am I looking at? The mower has/had great power, but it was/is missing a gear. Still, was doing a good job cutting my rough property which is a bit over an acre. What other issues could this be if not a governor?



I appreciate everyone's help. I basically need help deciding if this is fixable, or if I am looking at a new mower. Thanks.