Eva;
What year is your mower? Do you know that MTD is made by Murray inc. Now to try and anwer your question. Looking down from the top of the cutting deck. There are three pulleys as you said. Look at each one to determand witch ones go to the blades. These will be the ones that will have a cage like device around them. The one closestto the middle is called a ideler pully or a tension pully. You will know this because this pully will be spring loaded. Or will have a spring attached to it. It will move foward and back. The other two wont. They stay tight and just spend in place. Your belt will run either left to right or right to left. It doesn't matter. They work both ways. Working under the mowerand on top of the deck place the belt around one of the outer pullies. Now take the back side ot the belt closest to the back wheels and run it to the other side. So that the belt runs stright across the back of the deck. From left to right. Now on the frount of the deck put the belt togather like making a complete loop. You will have plenty of belt to work with. Now take the side closest to the middle pully witch will be wider that the others and put the back of the belt against it. If you have done this right you will have a long and short length of belt. You are almost done. Put the part of the belt facing the motor and carefuly put the belt around the pullt on the motor. You can draw a picture on paper and it should look like a arrow in shape. Facing right or left. Please unplug the spark plug first. Do not touch the mower befor you do this. The motor will have to turn enough and that might start the mower. And we don't want that to happen untill we're ready too! Sure hope that this helps.It realy isn't hard to do . It just sounds like it. Good luck and if you need a copy of how it looks let me know. I will be glad to send one to you.
Lester (chetsbro1@cs.com), July 2004
