I have a Ferris ZT mower w/a CV740 engine, About 2 years ago it started using oil, smoking on start up. I understand Kohler had a problem with head gaskets on that motor. Replaced the head gaskets and all was well, a least for awhile. Next problem was loss of power. The fuel line inside the tank is flexable plastic. Where the plastic line connects to a barb fitting entering the tank, it had cracked. This acted like I was running out of gas while having a full tank.
About a month ago my neighbors Ferris stopped and wouldn't start. Same fuel line problem. I replaced the fuel line and it's up and running again.
I don't know if Sears uses the same system, but it's easy to check out.
Best, Bill