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Dufour 27 Newb
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Discussion Starter #1
Dear All,

We have a very old shurflo diaphram type fresh water pump on board and not withstanding the age (20+ yr), the 12v motor seemed to work pretty well and only complaint was the pressure on the external shower.

So we tried opening it up for a bit of a service but found nothing particularly wrong! We cleaned it, oiled the shaft and gasket and diaphrams looked ok so we put it all back together but it is not pumping any water (zero pressure on the intake) - anything we can check to try and get some life back into it?

thanks

J.
 

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have you tried forcing a prime on the pump?

You might consider a rebuild kit. The Jabsco I have done included diaphragms. If I recall, there was a particular way the diaphragms had to go in which wasn't obvious. If you've flipped a diaphragm wrong way round it won't pump. Any little grains of dirt can mess up those diaphragms, needs to be real clean inside
 

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Learning the HARD way...
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Buy a whale? IMHO and limited experience they are a much better pump.
 

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Dear All,

We have a very old shurflo diaphram type fresh water pump on board and not withstanding the age (20+ yr), the 12v motor seemed to work pretty well and only complaint was the pressure on the external shower.

So we tried opening it up for a bit of a service but found nothing particularly wrong! We cleaned it, oiled the shaft and gasket and diaphrams looked ok so we put it all back together but it is not pumping any water (zero pressure on the intake) - anything we can check to try and get some life back into it?

thanks

J.

Diaphragm pumps are self priming, so it likely went back together incorrectly.

Most "fresh water" pumps are set for 40 PSI OFF and 25 PSI ON... This is a pretty low PSI for a shower.

I generally use "washdown pumps" for domestic water if the boat has a shower or water filtration system. They are the identical pumps with the only general difference being the pressure switch. Our boat has a 70 PSI OFF and 40 PSI ON pump and the difference was night and day between the old 25/40 pump we used to have..... If you move to a 60-70PSI pump however your on-board plumbing better be in good shape. What did not leak at 40PSI may leak at 60-70PSI...

Whatever you do avoid the VSD or variable speed pumps.... (Arghhh...)

With some of the older diaphragm pumps you can order a higher pressure switch, if it is available.
 

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Dufour 27 Newb
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109 Posts
Discussion Starter #7 (Edited)
thanks all for taking the time to respond! I will double check why the self priming is not working (any tips on how to manually induce it?) and the other points mentioned in the thread.

Should I expect to feel decent suction on the intake?

cheers
 

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Definitely check the check valves. Since you just took it apart and found nothing wrong, there is a high probability they didn't get put back in right.
 
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