What kind of water is it pumping? Sump pumps are dead easy. If you undo that union you can pull the whole pump out. Buy a new pump with the same dimensions, spin the MIP out of the pump, Teflon tape it, spin it into the new pump and put it back in. You might also find out that the pump is just jammed or only need to replace the float.

Edit I see it's pumping rain water into the house, cool what for?

Anyways I'm surprised you can't get a plumber this sort of thing is easy money, you should be able to figure it out yourself.