The deal is the FSM says that the center of rotor and clamp should be in line, but I have to turn mine 180 degrees out and then it was fine... I am willing to bet that you are going to have the same problem with the one you just bought. If it runs really rough like it is, mark where it is on the case, take it completely out and turn it 180 and put it back in, I bet it will run like a champ!