Small Engines (Lawn Mowers, etc.): Kohler CV15S Burning Oil

Question
I have a John Deere LT150 tractor with a Kohler CV15S engine. It recently started puffing blue smoke (oil) intermittently, mostly when under load. Especially with the mower deck engaged. The engine has to be fully warmed up. I thought I might have a blow head gasket so I replaced that this past weekend. I didn't see any evidence of a blown head gasket. I also cleaned the carburetor thoroughly. I noticed what I thought was an excessive amount of oil from the PCV tube going into the carburetor intake. After the head gasket replacement it ran fine for about 15 minutes and then started belching blue smoke again only worse than before. Should I be looking for a broken oil ring or compression piston rings? I didn't notice any cylinder scuffing when I had the head off. Could the head get pressurized and force oil past the valve seals?

Answer
Yes, the engine can get pressurized.

Did you download the engine service manual from Kohler's website?

You really should perform 2 tests:

1) Crankcase vacuum test.  Make sure the engine is creating and maintaining vacuum so the crankcase does not push out oil.

2)  Leakdown test.  Checks the condition of the cylinder, piston, rings and valves...to make sure there is no excessive loss due to worn parts.

What weight of oil are you using?

Did you torque the head?

Eric