I’m sorry to say but I don’t reckon that engine will do much work before giving up the ghost.
The only bit that looks as though it’s been rebuilt in the last decade is the exhaust deflector.
I’ve had a few Greenfields and they need a decent mill on them to be reliable. A good one will outperform most fancy zero turns. I’d be looking for at least a 12 horse engine, preferably more.
There are a few floating around because the mower frames on many of the imported ride-ons chuck it in on our rougher lawns well before a well-maintained engine.