I have a simplicity pacer that stalls when the PTO is engaged. If I disconnect the belt from the pto to the blades the mower does not stall. As soon as I reconnect the belt to the blades the mower stalls when the PTO is engaged. I checked the mandrels and they are not bound and I have replaced the bearings in one of the mandrels and that did not help. Any suggestions/advice would be greatly appreciated.