I work in a small engine shop. We see that a lot on those engines. Have you tried adding an extra clamp beside the existing one at each end? That seems to help sometimes.
Kohler uses a special hose in an effort to combat the problem. It is not 3/8" fuel hose. And the clamps they supplied in the last kit I put on are as good or better than the chinese wonders you get at Auto Supply.
The problem is the hose material tends to creep out from under the clamp, then it begins to ooze. And the heat/cool cycles the hose undergos doesn't help either.