hzatph wrote:
It can be tricky. Have you tried flooding the outlett hose while the pump is
running? Put a hose pipe or similar into it. I know that initially you will
be opposing the pump, but it will flood the impeller and once it is flooded
you can remove the hose pipe and it may pump out as you intended.

I had thought of either attaching a wet vacuum to the outlet and
sucking the damn air out, or trying, as you suggest, to force water in.
I suspect the latter will only push water out the bottom of the pump
though - it's open to the water that the pump is sitting in.

The impeller is, weakly, pushing water out. But a finger over the
outlet can stop the flow, so it's really only just catching water.

--
"Diagonally parked in a parallel universe."