Small Engines (Lawn Mowers, etc.): LT 155 blade rotation, john deere lt 155, belt tension

Question
I have a John Deere Lt 155 with two blades and only one of the blades will turn when I engage the blades.  One turns fine the other does not turn at all.  The belt is obviously stretched and needs to be replaced.  I am wondering if replacing the belt will solve this issue or is there more to this problem?  Thank you!

Answer
If yoou have only one blade turning then it is defintely a belt tension issue.
Check and be sure that the belt idler tension spring is still attached.
This is the spring that attaches to the belt idler pulley to maintain a steady tension on the belt.
If that checks out then your belt needs replaced.
Let me know what you find out.
If you want please rate my answer.