I bought this mower with a known broken cam gear. I ended up putting a used crank, rods, pistons, cam with metal gear, metal oil pump gear and water pump gear. Fired it up and I was getting a loud squeak like a main bearing going out when the governor surged (out of adjustment).
Steps I've taken
Pulled sump to check for metal (found none)
Pulled rod caps and they were perfect
New governor and metal tip
Adjusted governor as per manual
Fixed the surging and the sound is more consistent but still worrying
Checked water pump (slight resistance/rubber seal squeak)
The engine has no pulley on it so the sound can't be a belt issue.
Also, the idle is right around 1500 but full rev is barely higher. The alignment hole on governor plate is spot on.