Too long , too short, too thin , too thick , wrong colour, won't bend, gemlins keep biting my fingers.
Care to explain what the problem is ?
The belt is actually a std B section x 90.375" double kevlar fibre cotton wrapped.
Goes on in an L shape from the engine around the left of both idlers then around the right upper pulley.
The idlers it goes around are the 2" wide ones almost the same diameter.
Some times you can put a long wrench on the nut on the pulley to give you the extra leverage.
If that is not good enough try a ratchet tie down from the tension arm to the front of the mower.
The springs are not all that strong but they are in a place where you really can not get any purchase on them.
Some tie it works better to fit the belt to the deck, sit in front of the machine with your feet against the deck then pull on the belt, you will not hurt the belt they are kevlar & very strong in tension.
Just make sure you do it with leather gloves on to avoid pinching your fingers when you let the belt go over the engine pulley