Hello all!

I was wondering if someone could tell me whether or not they believe the drive belt on my lawn mower needs to be replaced or if they knew of another issue that I need to look at.

The mower has been sitting under a thick rubber cover for about 2 years now. When it was put under there, it was believed to have a problem going forward, and only in reverse. After pulling it out, fixing an issue with the carburetor, and getting it running, I have gotten it to go forward. There is a knocking sound that comes from underneath as you press in and release the pedal for the variable shifting transmission. It is the drive belt that is making the sound. I haven't been able to drive it around very much as the tires are dry-rotted and I have yet to replace them.

To help with identifying the issue, I recorded a video of what happens when put it forward and let off the pedal while it's engaged. This is the link to the video that I made. I apologize if what I'm saying doesn't make sense, as this is the first time I've worked on any kind of lawn mower.

The lawn mower info is as follows:

Bolens by MTD
LT5
Model # : 13am762f765 (2005)
15.5HP
38in Deck

This is the link to the video:

https://www.youtube.com/watch?v=NJRv8dx9qME&list=UU2JoD3VW5TJqTz0BFRmasyQ

Any help would be greatly appreciated!