Pump loses prime after repair

I recently purchased from you an ejector for a Pulsafeeder chem tech pump.
Installed it as instructed and everything worked fine. Pump and ejector still work fine but pump loses its prime when it shuts off. Possible solutions? Thanks Bill Rutledge
Installed it as instructed and everything worked fine. Pump and ejector still work fine but pump loses its prime when it shuts off. Possible solutions? Thanks Bill Rutledge