I have a Metro 36 with a Kawasaki FB460V. It's hard to start and only idles at a higher rpm that normal. The manual says minimum compression should be 43 and mine is 35. I'm going to rule out a leaking head gasket today but it says to check spring length/valve stems which are no longer available. I could buy some rings(around $50). I didn't have a problem with this engine about 20 years ago where the valve seat came off the block. Someone suggested I peen over the edge of the seats so they stay on the block. I has to use a punch tool and hit the block near the seats and bend the metal over the seats. I was surprised it actually worked. I heard the engine was recalled but I missed that notice since I was the 2nd owner. The deck and everything on the mower is in great shape.
I believe a replacement engine is around $1500. Not sure I can do an engine swap with a kohler/B&S or another make because of the mounting alignment.
I'm thinking it's time to let it go and getting a used one off FB or CL.
I pulled the cylinder head off and immediately noticed the valve seat on the intake loose like it was before I peened it 20 years ago. I peened it again but the valve did not seat properly. I resurfaced both valve seats and lapped the valve seats. I also replaced the intake valve. 2 pulls and it started right up. I guess we'll see how many more hours/years I can get out of it.