Blake water pump not pumping water

I've recently purchased a Blake water pump. On attaching the pump and starting it up using a
Lister the pump isn't pumping. I have taken all the covers off and split the pump apart but can see nothing a miss. I visited a steam fair yesterday and asked around and was advised to fill the top cylinder which I tried but the water just came straight out the inlet. I'm at a loss now of what could be wrong, I will say that the pressure valve doesn't move when running either.

If anyone could shed any light on this I would be very grateful.
Thank you
Barrie

Needs priming I reckon, can you turn the inlet pipe up so you can pour water down it? If you can then fill it up and while the pump is running put the pipe back under water with your thumb over the pipe to stop the water running out. Or the piston cups have dried out and need soaking in veg oil to soften them up again.