I have York forced-air furnace, about 17 years old. When I turn the system on, the blower motor makes a buzzing noise, but doesn't turn the fan. I can get it started by removing the cover, giving the fan a spin, replacing the cover, then turning the unit on. It works fine this way. I've looked at some of the other posts here and it seems like it might be the capacitor or the relay. Any thoughts. Thanks in advance for any advice.