Started the 310 today and noticed that the bolt and washer for the large dual pulley towards the front of the machine was lying in the engine compartment. Also there was a three inch square piece of metal lying on the ground (is this a key). When i try to reinstall the bolt and washer, the pulley just shakes and the bolt becomes loose again. HELP!! What could be the problem? Where does the little key go or where is it from? How do I tighten the bolt?