I have a John Deere self-propelled lawn mower. My pull cord is shredding and I would like to replace it. I am sure it isn't rocket science and I am sure there are experts out there who have done it before. I would rather play it safe before attempting to replace it so I don't make a mistake. Can anyone provide me with tips and/or instructions on how to do this? Thanks in advance for any and all help you can provide me.cpd2591@aol.com