Thanks can you tell me where this belt is?
Take off the large black cover on the front f the mower. Under it you should find the timing belt. You will see the belt tensioner also. Loosen this tensioner until the left side pulley can turn freely when you loosen the belt cogs fron the pulley. Carefully turn the left blade until it is at 90 degrees to the right pulley. Hold the pulleys in this position and retention the belt. Double check to see that the blades stay at 90 degrees.