Probably not worth the effort. If other good engines can still be found in your region at reasonable prices. I said probably as you have no solid indication of what the actual reason is. I would still try to start it. See what the compression numbers where like after it ran awhile.

It had not run for a long time so look hard for past vegetable oil use in the craze. If it was a past veggie engine I would pass it by. A veggie diet may be good for people. Not as often for these engines. The rings could be glued solidly in the lands with sitting.