Hi;
I have a lx127 1992 lawn tractor . I change the traction drive belt but it the still engaged.. cannot let the motor idele unless in neutral ! What is the problem . Thank you !

Hi,
First, I think you probably refer to a Deere LX172. I will proceed as if that is your mower.
If you used the OEM(Deere) belt, there should only be one place that would cause this. That is the idler near the engine pulley. It should be centered in its slot front to rear. Putting it otherwise will prevent the clutch from fully working.
If you opted for and aftermarket belt, the above still holds true but there are two other adjustment points as well. A bit more than midway rearward is the clutching idler assembly with a flat and a V idler. They are in slots. Tension can be decreased by moving the flat idler outward(toward the frame and the V idler inward(toward the center.) All three can have some affect but only have a limited range in which they are effective. In the case of a non-original belt, it has to be close to to the correct length.
The first on mentioned is by far the most important and shoud be done first.
Peace,
Clarke