2001 31 open head issues

[Akgleick]

I'm really hoping someone can help me. I am getting black water coming back into the bowl slowly after flushing. The toilet that came with the boat was a jabsco and it the same thing was happening. Here is what I have done.

Replaced toilet with raritan marine elegance
Flushed out vent and vent line.
Talked with tiara customer support
I used 1 gallon of raritan CH to clean out the waste hose

I called raritan they said it seemed there was too much pressure in the hose and it was slowly getting by the joker valve.

The hose from the head to the tank goes thru the bulkhead at the top then drops down along the floor under the sink and then up to the back of the head. I don't think black water is coming from the tank but is the stuff sitting in the hose.

I am $700 into this so far and still have the same problem. Any help would be greatly appreciated.

Thanks

[Uhehner]

One step at a time.
First loosen the cap for the holding tank pump out to relieve any pressure in the system and leave it loose all weekend to eliminate that as a possibility. Then let us know what happens.
Capt. George

[anthem]

excellent idea Capt. George. The vent may be blocked.

[Akgleick]

Thanks for the reply. I have tested the vent and it is open but I will try this today. Stay tuned

[Uhehner]

Do you have an in-line filter? Perhaps it's blocked. The loose cap will tell us. Capt. George

[Dazzle]

I had a similar issue with an older 31. While installing a complete rebuilding kit in the head I discovered a yucky joker valve. But that was not the only problem; the hose from the head to the Y-valve was plugged and had to be replaced.

[Akgleick]

All fixed. The new raritan toilet had 2 defective joker valves. The were deformed, looks like they were heated with a torch. Thanks for the replys