I tried (as others seem to) install one of these pilot jets and after less than half a turn it stopped screwing in. I didn't try to oil it or force it, just took it out and measured it. The upper main shaft, which has the size marked on it, is actually wider than the original pilot jet that came with the carburetor (KOSO OKO PWK). The same overall length and threads look the same, but if you look down where you put the screwdriver, it's thicker.
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