Water Pump issue

[Concord]

Looking for input on our water pump/impeller, my friend was commissioning our 1978 A4 and everything went well except the water pump was not drawing water. They spent some time trouble shooting and finally they were able to run the engine with the stainer not in line. Engine cooled down and controlled at proper temp.

99% sure the issue is just an airleak in the strainer because they opened it up to make sure it was empty and clear. During diagnostics they found the wear to the seal (cork) a bit out of round.

My question is regarding the pump, never had a lick of trouble with it and rebuilt it a few years ago replacing the seals and the internal shoe. Flow was great after the rebuild and ever since then....

During the trouble shooting they tried priming the pump to see if it was airlocked and found when they poured water in the discharge it came out the inlet and I was wondering if that was normal. There seems to be a gap behind the impeller that is allowing water to get by. As I said when they took the strainer out of line the engine ran fine and the flow was good. (Strainer is probably 25 years old and never serviced so I am sure it could benefit from new seals throughout)

[CalebD]

Are you sure you used the correct impeller size for your water pump?
Which brand of water pump is it? (Oberdorfer/Sherwood/MMI?)
Model?

If you replaced the impeller with a slightly smaller one, that would explain why water placed in the downstream hose would leak out the inlet.

[Concord]

Impeller

Yes we have an Oberdorfer pump (MMI Product No. - CSOB_02_63) and have used/replaced the same impeller for years. They compared the two side by sideand the new impeller was identical to the old one.

We never had a flow issue in hte past so it may have always been able to do this but it is not something we ever tried.

I am just curious if others have seen this.

[roadnsky]

You may want to read this thread...

http://www.moyermarine.com/forums/showthread.php?t=7688