Jabsco toilet issue after service

[VicS]

Another thought : since the external black lever switches between input and discharge is it possible that either the twin top valve itself or the black internal lever are displaced so as to allow input and discharge at exactly the same time ? The length of the discharge pipework and volume of the tank are not necessarily a barrier to external mixing since they will already have contents similar to the fresh contribution.

One of the Jabsco Tech videos I mentioned in #37 explains how the Jabsco pump, including the wet/ dry bowl lever, works . I recommend you watch it

 

[Graham376]

I was really careful to follow the instructions but I must have put something back incorrectly. The joker valve at the bottom has the 3 short pegs , can it be in incorrectly? Surely the waste must be passing at the top stroke of the pump and hence the issue is at the top valve? I can’t see it getting past the piston o ring?

The Joker valve is the circular one way valve with 3 lips right at the bottom, not the flap valve. As the Joker ages, it distorts and deposits build up around it, restricting its opening and stopping it closing properly. When replacing it, the crud around it should be chipped away to allow the new one to seat and function properly. The top of the pump unit only handles the flush water not the waste and it's virtually impossible for waste to get past the O ring.

If the outlet pipe has a large build up of crud and is becoming blocked, it is just possible for back pressure to force some waste back through the joker and flap valve but that would appear at the bottom of the bowl, not in the flush water. What you're seeing is either deposits built up in the inlet pipe being flushed through (normal after layup) or, as suggested above, the seacocks are too close together.

 

[bluerm166]

One of the Jabsco Tech videos I mentioned in #37 explains how the Jabsco pump, including the wet/ dry bowl lever, works . I recommend you watch it

Thank you Vic for your link.Unfortunately Bill and Ben from jabsco don't cover this particular point so i wonder if you could explain your difficulty with this post in your own words.