Small Engines (Lawn Mowers, etc.): kohler kt17qs spec 24301, heavy duty mechanic, john deere 317 garden tractor

Question
this engine is blowing excessive gas/oil out of the oil filler plug. as a heavy-duty mechanic i don't have much experience with small engines. but i would like to attempt to rebuild it if it is worth it. I am either guessing it is piston rings or valve train problem. how do you suggest i diagnose this problem and where can i find a service manual for proper torque procedures and specs? Can i purchase a downloaded manual? This engine is out of a john Deere 317 Garden tractor.

Answer
Kohler manuals are found here: http://www.asberry.net/Kohler.html

There's gas blowing out the oil fill?  A leakdown test is what we do to determine cylinder sealing.  Often oil will be blown back through the fill when the crankcase breather is stopped up.