In that hobbico pump, there is a motor, with a small disc attached to the shaft. On that small disc are two protrusions that drive another disc connected to the pump. More than likely, one of those two discs has broken. Take it apart, and fix it with CA glue. I did this with mine, and it lasted another several months. It finally broke again, and I just bought a sullivan. Haven't had any problems with it yet--it's lasted most of this summer so far! It's direct drive, so gears breaking won't be an issue with it!