I acquired a free hot tub and have been working through problems. I put new bearings in my main pump (Waterway executive 48 4.5 hp). After getting it put back together, the pump will not start on low speed (just hums). I can turn it on high, it starts, then turn it back down to low and it runs fine. It runs fine until it reaches the set temp, shuts off, and when the water cools off enough to start back up again it just hums. I replaced the start capacitor today and it did not cure the problem. What else could cause these symptoms? As a side note, before the bearing change, I did not have the bad cap symptoms. Is there something I could have messed up? The cap looked like something had melted out of it, a black tar –like substance. Thanks for any assistance