Small Engines (Lawn Mowers, etc.): Deck leveling, blade, wheels

Question
I have had this mower (Murray) for about five years now, and have had no problem leveling the deck to this point. I can't seem to get it level anymore. I have checked the blades to identify if one was bent, all are straight. I have tried over and over, but the left side cuts lower than the right. The deck only has two deck wheels, one rear left and front right. Problem is front left (no wheel) is cutting too low. Any suggestions?

Answer
When you line the blades up, tip to tip, are they the same height?  Don't forget to rotate the blades, one at a time making sure both side are about the same height.

Also, check for play in the shafts.  Grab the blade and wiggle it all around, up and down and compare the play.

Let me know what you find.
Eric