Name:   lakngulf - Subject:   Serpentine Belt Date:   6/12/2016 2:22:07 PM

I had to replace serpentine belt on my Mercruiser 5.0 motor.  Replacement seems simple enough and belt tightening without problem.  BUT, when I start the engine the belt around the main motor pulley begins to rise forward over the pulley.  I put it back in the grooves, try tightening more, and then I put back in grooves and try it a bit looser.  Any method and the belt begins to rise forward over the pulley.

You can see the rise at the red arrow.  Also, at the blue arrow the belt moves forward.  Any suggestions?  Second picture is closeup of the rising belt.  It kicks out of the grooves as soon as the engine starts.