this may be a silly question but i bought a a simular pump on ebay (2639) that i am going to hook up next weekend but a little unsure how to wire it. There are 4 wires coming out of the pump two are black and wired into the capacitor. The others are blue and brown. Does it matter which one is common and positive? if so which is which? sorry for the dumb question but not sure and do not want to mess up.

THanks