Those eninges are well, good for a golf cart and that is about it.
I have a Yamaha golf cart and I had to rebuild the engine last year. Mine is a newer model, but the engine is simmilar. They do have bearings on all the rotating surfaces, but the rod is weak and so are the counter balancers.
After visting with the local golf cart shop they said if you over speed these engines the conter balancer will break. And if the rod is shot it will start knocking. And they don't like long run times, they are designed to run for short spurts.
SO I'm playing with fire on my golf cart. New engine and bypassed govenor!!
Come on............YOU didn't think I could leave it STOCK!!!!!!!!!
Sell it, it isn't worth much. You need the starter/generator anyway to make it work and be usefull. Which is the expensive part.
Paul