I recently purchased a new Super Z 60/28 EFI Kohler engine. I changed oil and filter at 5 hours. I checked oil at 17 hours and it was down 1/4 below full mark, added oil to bring up to full mark. This mower is used for homeowner use only not commercial, it takes me only 3 hours per cut. I checked again at 20 hours, it was down 1/4 below full again. I did not add any this time but proceeded to cut for 3 hours. Upon finishing and allowing mower to cool completely, the oil level had dropped down to add mark. The mower now has a total of 23 hours. The grass is not overgrown and the mower is not forced and I have not abused it whatsoever. I asked my dealer yesterday and he said it was possible that there could be a crack or flaw in the breather seperator, which is a small rubber-plastic type grommet. Has anyone experienced this type of oil use problem, if so how was it solved?