91 M 103 w 124 belt tensioner adjuster
 

I hate to sound like a space cadet ...but here goes. the "tensioner adjuster" that fits on the back of the boss ( two flats and round) of the belt tensioner has an offset to the part that fits on the boss. Does the offset flat on the round part go flush with the tensioner or on the out side? I usually remember how things come apart but I couldn't see what I was doing when the parts separated.



Getting old isn't for wimps as your eyesight and memory suck!

The manual (M star) showed the orientation
 

I found my old disk and voila the belt section showed the correct fitment. Sorry to be such a time waster....