Pull the volute cover off the pump and check the mesh on the impeller. There may be some loose mesh that's slowing down the impeller. If you see any strands, just cut them off.
Even with the start up problem, the pump should start on it's own after about 10 secs or so. The pump won't (or at least shouldn't) burn up because the impeller is spinning, but it's hoping up and down. You can get it to start by blowing into the airline.
If you still have problems, contact Rob at MarineSolutions. He may even send you a new impeller.