My kohler 16hp(2003ish) would not turn over so I checked oil and smelled fuel. I drained out the oil(usually 1+ quart) and nearly filled a gallon jug up! I replaced oil. Two questions 1) it likely will continue leaking some fuel in, does this ruin oil or can it take some? I need to mow lawn 1-2 times to burn off rest of fuel in tank. 2) Is putting a fuel shutoff in a fix? I think it flows into engine when not running slowly due to gravity setup.