How does a marine toilet work?

TQA said:
One side has the pump rod attached. The volume of the pump rod is the difference. If you have a problem visualizing this make the pump rod much thicker. The swept volume will be less on the rod side.
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Now you have pointed that out, I agree with you. I would think that the volume of the thin rod is pretty negligible.
 
pvb said:
That's right too. But, this means the volume of flushing water is less than the volume of waste water removed. This rather contradicts others' observations.
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+1

All the Jabscos I have ever seen will eventually fill the bowl with seawater if you keep pumping using the inlet setting so I have always assumed that this is a design feature. I don't know how it works though. Perhaps something to do with the different hydrostatic levels at the inlet and outlet end?

Richard
 
tudorsailor said:
Perfect! Many thanks

Will now get armed with equipment to see why "the waste goes out" but not much water comes in! I think I need a new O ring on the piston.

TudorSailor
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Or you may find the inlet pipe blocked by weed/crud sucked back in. This has happened to us several times when the symptoms match your description.
 
My 11 year old Jabsco pumps out more than it pumps in, I assume because the Blakes inlet seacock has a strainer plate over the outside, the trick is to stop pumping just before the thing decides to "spit back", if I stop at the bottom of the stroke, the bowl will fill by syphoning. So the comment about filling more than emptying is outside 11 years of experience with mine... I'm replacing this winter, and noticed the compact is available for £104.95, the Standard for £129.95...
 
The seamanlike way of dealing with the OP's query is for him to do what we all do - take it apart and have a look at the innards. It would be as well to have spare gaskets and other bits, but, if he can bear the cost, he will at least have learned something in the process and be cured of headphobia.
 
johnalison said:
The seamanlike way of dealing with the OP's query is for him to do what we all do - take it apart and have a look at the innards. It would be as well to have spare gaskets and other bits, but, if he can bear the cost, he will at least have learned something in the process and be cured of headphobia.
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My plan was always been to dismantle and see if I can make it all work. I thought I would ask how the pump works to at least try to understand how it should work before dismantling. The instructions for maintenance are poor to say the least. The Youtube video is most helpful.
So camera at the ready to record how it comes undone.
Surely if I was truly unseamanlike, I would simply get the toilet replaced with a new Jabsco
Thanks

TudorSailor
 
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