Tools, Sharpening and Power Machinery - Belt tension on Trimmer mower

I am replacing a broken belt on a DR trimer mower. The belt requires v-belt 4L450, (from the manual) which I'd purchased. After installation, the mower continues to rotate after I disengaged the handle bar lever. The cable is already adjusted to the "most loose" but the trimmer continues to rotate or engage for cutting and it chatters. (like the belt is too loose) Both springs are normal and cable is fine. Did I get the wrong belt? Anyone have a DR trimmer mower and have more knowledge on this please let me know?

Did you do any adjustment on either the safety cable or the engagement cable (the handle on the right handlebar?)? You may find that until the belt heats up a little, it may be too tight. Make sure the hooks in the levers underneath are laying flat and aren't cocked up in any way. Doncha just love the machine? Ours is really my wife's.....I just have to keep it going for her.

Yes, the cable was adjusted. All springs are aligned. It still continues to spin. I can assume the v-belt is too tight. I can't do any more adjustment. It is at the end of the adjustment bolt on the right side of the engagement bar.

I would take the belt to a auto parts house and have them get you one maybe 1/2" longer. That should give you enough slack to let it disengage. This is to say that not all things are made to exact specifications, and the belt they provided may have been "mis made". Good luck with it, as I know it is a real workhorse.