Small Engines (Lawn Mowers, etc.): 16 hp single cylinder Kohler, crankcase, john deere

Question
My 1977 John Deere, with the 16hp Single Cylinder Kohler engine, has started to get some pressure in the crankcase.  First, is this normal, or does this mean I have some type of bad ring or damage to the piston.  The machine seems to run fine, and does not make any abnormal noise.  It does overheat in a few minutes, so I have not used it since I noticed this.  How easy would it be to replace this , if indeed this is the problem? Or would I be better taking it in to fix, even though the machine is 25 years old?   Thanks for you help.
Jon


Answer
Hi Jon,

I agree.  The pressure is probably due to compression bypass.  Either through the rings or valve stems.  Normal pressure is usually vented through the breather.  You could rebuild or replace the engine but if the tractor is worn, it may be time for an entire replacment.  Doing it yourself would be involved.

Good luck,
Michael