Small Engines (Lawn Mowers, etc.): Kohler 25hp, Ring problem ??, ransome mower, valve seals

Question
I have a ransome mower with a Kohler command 25, spec# 68514. I was having a problem with heat, I cleaned it, check the muffler, removed and replaced the valve seals and head gaskets(both had small leak), still at full rpm the muffler started to get red(internally), I then removed the hydrualic lifters and cleaned them and changed the oil and filter. This seems to have stopped the muffler from getting red, but in the process I found that there is a lot of pressure from I presume blow by, when I take the oil fill cap off. My question is, Is this normal because it has no exhaust seals or does it need a ring job ? I appreciate any and all help, thank you !!

Answer
 Hello Mark:

 The Internal Pressure you are Talking about is Normal. As Long As the Crankcase Vent/Breather isn't Allowing Oil into the Carburetor, then the Engine is Fine. If the Pressure was to High then the Crankcase Vent/Breather would Allow the Oil to be Sucked Into the Carburetor and the Engine Would Smoke from the Oil. You can View a Breakdown of this Engine at this Addy http://www.kohlerengines.com/service/manuals/index.jsp and Follow the Instructions to Locate the Service Manual for this Engine. Hope this Helps. I am here if you Require more Assistance. Thanks.

 Good Luck

 Respectfully

 John