Downriggin,

You still got the upper end, but no water pumping out? Or is the powerhead the problem?

The pumps are pretty easy to work on. Take out the (6) or (8) bolts that hold on your shoe.
Then you can get up close and personal with the impeller. Take a look at the clearanse between the edges of the impeller and the pump sleeve. This should be fairly tight, maybe .002 clearance.
One nut, and off comes the impeller with the stack up of washers. Then you can take a look at the sleeve itself. If there is no major defect you are good to go. When you put it back together, take one or two of the washers from the top of the impeller, and put them on the bottom. This decreases the clearance between the impeller and the sleeve.

While you have the impeller out, go ahead and touch up the leading edges with file. Not to much, you don't want to take the impeller out of balance. Also take a look into the pump tunnel for any obstructions.

I have done this twice on my motor, and I spent more time touching up the impeller than the disassembly and reassembly. About an hour.

Hope it helps. Good luck