I have read a ton of post on the WEB regarding this subect, and I am havig the same problem wth a 2004 Murray model 425001x8b. I have tried everything. I bought the mower from my neighbor that moved. As far as I could tell he did not have ths problem. Here is my theory. I put a mulching kit on it shortly after I bought it and I think that is when it started, I do not feel like it does that good at mulching and the tires run over all the half mulched grass causing it not to cut even (on the discharge side). I am going to remove the mulching plug and see how it does. Any comments?