I got one for you, I have a Kohler V-twin that has a distinct click to it. You only hear it when you shut it off and it makes it's last RPM or two. I have a single cylinder 13HP cv dose the same thing. Am I hearing a hydraulic lifter or what? Both engines run fine and quiet while they run so it's just when I shut it off. Got any ideas!!
Welcome to the forum!! Maybe it's the deck pto on these making the noise when the engine rpm slow? Sounds like something that turns all the time (ie blade pto or hydro drive/trans.) when running might just have enough resistance to make the engine stop suddenly when shutting off.