Water pump on VP C5 petrol engine not pumping?

[dickh]

Hi everyone - I've just checked the water pump on the VP C5 engine I've just aquired and it's not pumping water. The engine is mounted on a work bench, the pump is a geared bronze pump and it wouldn't suck up even 12" from a bucket. I had this type of pump on an Albin years ago and cannot recall any problems. Does this type of pump have to be below water level to work? does it need to be primed? or is it just knackered?

 

[pvb]

I don't think gear-type pumps generate much suction, so I'm not surprised it won't suck water up 12". When the engine's installed in a boat, it's likely the pump will be very close to sea level, so it would probably self-prime then.

 

[Freebee]

gear pumps are positive displacement which means once primed they have fair bit of delivery but will not self prime, so the suction has to be flooded to work. so yes it needs to be below water level to work