Small Engines (Lawn Mowers, etc.): blade turns but will not cut, pulley bolt, craftsman riding mower

Question
QUESTION: I have a small craftsman riding mower, when I engage the blade it turns, however it does not cut the grass, I am guessing that it is not turning fast enough.  How can I remedy this?

thank you

ANSWER: What is the model number of the mower?  The model number format similar to 143.xxxxx.  

Has the belt been replaced, adjusted or has the blade been replaced?
Let me know.
Eric

---------- FOLLOW-UP ----------

QUESTION: Model number is 247.270250.  Blade or belt has not been replaced, however they have been adjusted.  Belt is tight now (I believe it is aligned correctly), and when I manually turn blade the belts move and vice versa.  

thank you

Answer
The first item I would replace is the belt, part number 754-0495.  You can purchase the belt from Sears.com or MTDproducts.com.

With the belt removed from the pulley, the engine off and spark plug removed, engage the blade as if you were cutting grass.  Rotate the blade by hand and see if it turns easy and smooth.
Also, check the engine pulley bolt and engine mounting bolts to ensure they are tight.
Let me know what you find.
Eric