[jclark003]

I would start by disconnecting the discharge hose. Blow into it to see confirm it is open and clear. If so the blockage is either at the base of the pump or there usually is a check valve on the discharge line going out of box (if it's the box I'm thinking of). Unless it can get the water out of the box the pump will continue to run. Excess water will spill into bilge spaces tripping mid pump from time to time.