JPR,
If you have a way of mounting a small camera, or at least getting a camera above the hydros while the belts are engaged. Keep hands out of the area of moving belts by all means. Cameras are disposable, hands, well maybe not so much.
You may find that the belt is flopping around and getting into the cooling fan blade on one or both of the hydros. It is usually the right one from what I've found. Might want to contact the manufacturer if you find this is your situation.
Max