I'm pretty certain at this point it's the capacitor. That would explain why the trouble only happens at morning start up. Throughout the day, while it's running, enough power has been stored so if I turn off the pump to backwash or something, it turns right back on. Kinda like a car battery on its last legs may have trouble starting in the morning, but once the car has run and charged it up, you can shut it off and restart it as long as not too much time has gone by for it to run down. I have a second (identical) pump for my spa, which I'm not using right now because I have a leak somewhere in the spa return line, so I think I'll try swapping out the capacitors and see what happens. If that does the trick, I'll just buy a new one and replace it. I may just bring it to a rebuild guy, though -- it's a little noisier than it usually is (there's a higher-pitched hum going on) that I think might be the windings.