I just had a Kohler 20 hp with about 1900 hrs start using a lot of oil. I had been noticing oil leaking around the oil cooler, but didn't know how to fix it. I decided I needed to replace the paper gasket hoping I was just losing oil and not burning it. I replaced the gasket and it stoopped leaking, but it burned oil. There's a young guy I know who is a good mechanic and I asked him about rebuilding it. The engine had been well cared for and I thought I might take a chance. When he opened it up, he say it looked great. He said that you could still see the original milling marks in the cylinder and that the rod bearing still had a part of the original coating. He said that it looked like the engine had gotten hot and the oil rings had just lost their spring. He put in new rings and head gaskets and put it back together. This is the first of my engines to have a rebuild after using synthetic oil. If this is a true indication, I think it has been worth the difference in cost.