Just to follow up, it was about -20C earlier this evening and it spun fine, and did start after a fair bit of cranking. It would spin and then try to run for a longer and longer period of time (and then I would try starting it again), until it actually caught and run fine.
I also got ahold of Scott at Kohler (after getting forwarded to him from Kohlers twitter account), and he said they didn't have an anti-freeze kit for this engine as it was made for a summer job, but said that the best thing to do would be to get warm air from the exhaust to the intake.
So, I initially came up with just removing the heat shield from the exhaust, then fabbing a shield around the exhaust, up to just inside the bottom of the air filter cover. But then, as I was thinking about how it really wouldn't get a lot of hot air from over the exhaust into the intake (it would be better, just not that great), I came up with the idea of putting a hole in the heat shield, welding a short tube over that hole, making a plate that goes underneath the carb (mostly horizontal, with sides that go up, just inside the bottom edge of the air cleaner cover, with the same hole/tube setup that's in the heat shield), and then connect the two with a short piece of insulated flexible metal tubing.
And thinking back, this is the kind of setup they did in cars back in the 70's and earlier, when they had carbs. They had a heat shield over an exhaust manifold, with a short tube, and a short tube on the air cleaner housing with a valve that opened when it was cold out, with the insulated tube connecting them, so the carb would draw air from over the exhaust manifold in cold weather.
I also got ahold of Scott at Kohler (after getting forwarded to him from Kohlers twitter account), and he said they didn't have an anti-freeze kit for this engine as it was made for a summer job, but said that the best thing to do would be to get warm air from the exhaust to the intake.
So, I initially came up with just removing the heat shield from the exhaust, then fabbing a shield around the exhaust, up to just inside the bottom of the air filter cover. But then, as I was thinking about how it really wouldn't get a lot of hot air from over the exhaust into the intake (it would be better, just not that great), I came up with the idea of putting a hole in the heat shield, welding a short tube over that hole, making a plate that goes underneath the carb (mostly horizontal, with sides that go up, just inside the bottom edge of the air cleaner cover, with the same hole/tube setup that's in the heat shield), and then connect the two with a short piece of insulated flexible metal tubing.
And thinking back, this is the kind of setup they did in cars back in the 70's and earlier, when they had carbs. They had a heat shield over an exhaust manifold, with a short tube, and a short tube on the air cleaner housing with a valve that opened when it was cold out, with the insulated tube connecting them, so the carb would draw air from over the exhaust manifold in cold weather.