I don't really have any experience with these, but don't recall hearing anything.

Are you sure it's the engine and not the pump?

If you had oil in it then the governor is not working or hung up. You need to see if it is moving freely.
Hard to diagnose without seeing it. But a un adjuster governors do many strange things.
I would also suggest that you remove the shroud and gas tank. Only 3 nuts and look to see if the flywheel is hitting the magneto.
Remove the spark wire first.
Also see if the flywheel has any slop sideways. Also look to see if the flywheel bolt may have come loose.
This engine has a heavier flywheel.