1) BE SURE the washer is UNPLUGGED FROM POWER and drained before you take the black plug out or make yourself a funnel that will go from the front of that out to a bucket (I used an under bed hard plastic tote) you may have 3 gallons or so in there.
2) When the cover is off, you are looking straight in at the intake of the impeller. it has 4 fins and should spin freely if it's not blocked. (Mine had a color catcher sheet stuck in it.)
3) clean out any loose debris in the pump housing (i had a bobby pin, a nail, a metal clip that looked like part of the washer :(, and various rocks and gems from active young 'uns.
4) before replacing the black plug, be sure you have not fouled the threads that it screws in to. they need to be perfectly clean or your pump won't seal and you'll have leaks.
5) replace the pump cap -- white arm goes down in the groove at the bottom of the pump housing (there's an arrow on the cap inside)
6) power on and give it a spin!
Kevin, May 2010