My edger sounds like it is not running up to speed and it is sparking.

Most likely it just needs a set of brushes, if you keep on running after this starts you may need more than that by the time you quit. Check the brushes and replace them. If your brushes have a wire attached to them (shunt wire) you need to replace them with the same kind, do not put brushes without a wire in a edger that has brushes with a wire (it is there for a reason). If that does not fix the problem bring it in for service. Again running it too long with the problem can cause more damage which will be expensive!