Belt keeps popping off.

[Rich A]

Craftsman 2011 - 247.28881 7 speed Shift-on-the-Go lawn tractor.

What would cause the smaller vari-speed belt to instantly pop off when engaging clutch? Could this be caused by a miss-adjusted part of the linkage? The user manual does not have any instructions for brake or clutch adjustments and says to "contact the nearest service center" for those repairs. I thought the problem was the smaller idler pulley bracket which was slightly out of line and tilted downward a few degrees. I've since replaced ALL the brackets and belts with new OEM parts and the slight tilt of that idler pulley is exactly the same with the new part purchaced. I've tried various manufacturers belts as well as supposed OEM MTD parts from Sears, MTD etc. And also found some NOS parts that had the original brackets. Nothing works. Help !!

 

[Barrett50]

I'm new here, my first post. You have replaced the belt. Is the belt the exact same width as the old belt? Just from the photo, it appears the new belt is too wide for the idler pulley. Or - is the idler pulley tilting on the driven axis when engaged? If you still have it, use the old belt and see if the issue remains.

 

[Scrubcadet10]

double check that model number, it's pulling up a completely different drive system

 

[Auto Doc's]

I agree the small idler pulley is too narrow for the belt being used. A belt should never ride far to the outside of the "V" of the pulley.

 

[Scrubcadet10]

That belt isn't tensioned in the picture, so it may sit fine in the pulley when applied

 

[StarTech]

247.288810 appears the OP dropped the ending zero.

Which belt are you using? OEM belt PN 954-0241A [954-05040] which is 5/8 x 35-1/4 or the one Sears is claiming is the replacement belt [490-501-Y087 5/8 x 35-11/16]. If using the longer belt that may be the problem as nearly a half inch is quite a bit on the smaller size since adding 1/2 to circumference increases the diameter by nearly a 1/4 inch and these CVT systems are very sensitive to belt width and lengths.