Be sure to check out Ebay & Amazon for a New or Rebuilt Engine with warranty before rebuild. Might not be that much difference in cost. Never know.
They may have run the Engine without OIL. After the Fact,, then poured in Oil. I almost ran a Generator 11 hp without oil.
I put oil in,, and then stored the Generator for a year or so. Decided to crank the Engine up,, just to let it run for a while before needed.
Pulled, Pulled, and Pulled until my arm was sore. Cheap Junk I said. Cheap Cheap Cheap.
Then I decided to check the Oil. Didn't have a Drop in Pan. Had leaked out past the Drain Plug washer seal.
The engine has a low oil no start sensor. Put oil in,, and Motor Cranked up on 1st Pull. 1st small engine I've ever owned with a Low Oil No Start Sensor.
Another Testamonial for Checking the Engine Oil,, before Cranking on all Engine's.:thumbsup:
Good Luck