It kind of depends on what you "cleaned" it with. Go with denatured alcohol. It is quite typical for a OWB to slip after time. It all really depends on how much fuel/oil seeps down the shaft that the bearings grab. Cleaning the OWB is standard maintenance though. If there is ANY scoring on the shaft or ANYthing out of ordinary in the look of the bearing you'd need to replace it, the shaft or both. Sooner or later it's going to stop working all together. Your job is to replace it before it scores the shaft. Good luck with your new engine bro.