I have a JD 300 garden tractor with a kohler K341 16 horse engine that I recently overhauled. It runs great with lots of power but after running it for about 25 minutes it will start leaking oil out the front from behind the pto. I have replaced the seal twice, checked to make sure there is not a groove wore in the crank, checked the breather to make sure it is assembled correctly. Like I said it runs great with no smoke so I have no reason to think that I am getting blow-by causing to much crankcase pressure. The oil is coming from behind the pto clutch somewhere. Any Ideas? I have rebuilt and ran kohler engines in my pulling tractors for years but have never encountered a problem like this. I am pulling my hair out! Any ideas? Thanks Dave