My father gave me Lowe's 1642 riding mower but the drive belt keeps coming off. I have put a new idler pulley on and it still does this. I took the middle cover off and watched the clutch pulley when I was mowing and the belt seems to get too much slack in it and thrown off. Are there any belt keepers that are supposed to be there. I see no sign of any. What else could be causing the problem? Other than the belt coming off the mower runs and mows great. Thanks for any help.

Dustin

Is the belt new? They can get worn down (very rarely stretched though) and pop off. As for belt keepers, they can range from tabs to bolts sometimes.

I put a new belt on it when I did the idler pulley. I asked the people at the parts store for a shematic and it did not show any keepers for that belt.

There are 3 bolts--2 short and 1 long--- which attach the front of the transaxle case to the frame. Make sure they are tight. They are only 1/4 diameter bolts and will loosen and even fall out. When bolts are loose and torque is applied by releasing clutch pedal the transaxle will tip forward just enough to kick belt off. You will probably have to drop the deck to access the bolts.
Hope this helps.