Jabsco Twist N Lock woes

[MikeBz]

Jabsco pump stopped pumping water in yesterday. Pumping out working fine. Checked the seacock was open and no blockage. I had a service kit at home so took the pump home and dismantled it. One of the flap valves (is that the correct term?) in the top valve gasket had fallen apart, so I cleaned everything up, fitted the service kit & reassembled following instructions with the kit and various YouTube videos. Refitted it to the boat today and it still doesn’t pump in, but worse when you try to pump in water dribbles and squirts out from the interface between the valve cover and the pump cylinder (part names from Jabsco’s own pare parts list). Took it apart and double-checked everything, reassembled - same problem.

The only thing I could think of is that the top valve gasket is too thin and not making a seal, but checked it against the old one and it’s no different. So I’m stumped. Looks like I’ll just buy a whole new pump but I’d like to know why this is happening.

 

[ash2020]

Isn't it horrible when you find a fault, fix it and it still doesn't work! I feel for you. I can't picture the exact pump but is it possible to submerge the whole thing in the sink and see if air is getting in or out of the sealing gasket?

 

[MikeBz]

Isn't it horrible when you find a fault, fix it and it still doesn't work! I feel for you. I can't picture the exact pump but is it possible to submerge the whole thing in the sink and see if air is getting in or out of the sealing gasket?

It might be tricky. I did wonder whether to try pressurising it, but given that water gets out I’m pretty sure air will.

 

[Boater Sam]

Jabsco's plastic pump parts distort with age and once you have undone them they will not seel unless you restore flatness to the mating surfaces by rubbing them on abrasive on a piece of flat glass or a surface plate.

 

[johnalison]

I’ve taken them apart and not generally had trouble. Providing everything is the right way round and all that, it is mainly a matter of making sure that everything is properly lined up and evening out the tension without overtightening. A little silicon grease can help finally seal things.

 

[nevis768]

Its much easier to buy the pump as a unit, its not much dearer and no farting about, excuse the pun...
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