Small Engines (Lawn Mowers, etc.): Smoke from engine after 30 seconds, blown head gasket, john deere lt155

Question
My lawn tractor, a John Deere LT155 with a 15 HP Kohler engine emits smoke
from the front of the mower about 30 seconds after I start it and the smoke
lasts maybe a minute.  The longer the mower sits between uses the more it
smokes.  Sitting a few hours will result in less smoke that sitting a week.  It
doesn't seem to use much oil. It's hard to describe the smoke's color,
probably a little blueish but not real dark.  Is this something to be concerned
about?  Easy and cheap to fix ?

Answer
Several possibilities.
1 have you changed the oil recently, it holds 48oz not 2 quarts.
2 blown head gasket. This is kinda common.
3 Park the the tractor with the front tires sitting on a 2by4. If this solves the problem you have a problem with the oil drain back holes on the piston.
4 Trying to keep the oil at the full mark. Most Kohler engines have a knack of burning off oil until it reaches the level it really likes. Don't "top of the oil" until it's almost to the add mark. It's pretty common for this engine to burn oil until it gets to a certain point and then they quit smoking so unless the oil is closer to the add mark than the full don't worry about it.
DON'T DRAIN A LITTLE OUT!!!!! Let it burn out.