As soon as I find out what the problem is, I will post it. I mowed my yard Saturday and noticed that after about 30 to 40 minutes of mowing it started to show the power loss. The first 30 minutes or so, it would cut like heck. Then it would begin to bog down to the point of having to slow down to recover power. I shut the unit off and let it sit for about an hour to cool down. When I started back mowing, the same thing occurred. After about 30 minutes the power loss was very noticeable. I also noticed that the temprature gauge was holding well above the half way mark, unlike my other 331 that hardly ever gets to the half way mark. Very puzzling!! I am having the DFS system installed on the more powerful unit today. I don't think the one with the power loss could handle it.