-87 Carver 4207: Black water coming into toilet!?

[steve&tammy]

Hi all, thanks in advance for any and all help.
Ok, so forward toilet...just working through de-winterizing everything. Boat was recently out of water getting new bottom paint and everything was fine.
Boat was put back in water, I go to see it, walk in the forward head and there's water on the floor and the toilet is full.
I looked below the generator where the water inlet is connected to the seacock and the tube is NOT connected there. (They disconnect them for the winter).
I'm only saying this as there's only one other place (that I can think of!) that would bring water into the toilet and that's the black water tank.
I don't know why or how but it's full. I can run the toilet (again, not currently hooked up to the seacock water inlet) and it drains the toilet bowl but an hour later, it's full again
Please help!!
Thank you

[buster53]

First of all, you always pump out your holding tanks before you put your boat away for winter. Pump out your tank and do a rebuild kit for your head. It’s a job that needs to be done every so many years. Basically, your duckbill valve has gone bad allowing back water to come back

[Viper]

Ya back to the basics. Check your duckbill valve first. Would help to know the type of toilet you have....Crown? Sounds like the tank didn't get pumped out before winter or someone thinking they were filling the fresh water tank but filled the holding tank instead

[km1125]

Might also want to check the VENT for the blackwater tank to make sure it's clear. If there's no filter in the line then you can use a hose on the vent to force water back to a mostly empty tank (provided you also remove the pump-out cap so you don't pressurize the tank!). If there is a filter in the line you probably would have to take that out-of-circuit and check the rest of the parts individually.

[buster53]

I’m also guessing you have the Raritan Crown heads. I used to have a 3807 with 2 Crowns. I did the rebuild kit on both. The duckbill is the primary part but other parts are included as well. Takes a couple hours and anyone comfortable turning a wrench can do it. If I recall, instructions were pretty clear. Empty your tank first and then flush with 1-2 gallons of fresh water.

Quick question, what was the water like that refilled the head and overflowed on the floor? Nice and clean or not nice and clean.

[tomschauer]

Is the holding tank higher than the head? If not it shouldn't be coming from there.
Are you sure you don't have fresh water flush and a leaking solenoid?

[steve&tammy]

The water rising into the toilet is "not nice water". I do keep looking for where else it could be coming from other than the black tank. I'm awaiting on the marina to get someone to empty it.
As mentioned in my original post, the inlet from the seacock is not currently connected.

[bud37]

It seems to me there was a thread a while back with much the same problem....don't remember all the details but it had to do with the macerator and the overboard waste discharge system/ "y" valve as I remember it....

Is that something you have installed on your boat ?

[buster53]

The water rising into the toilet is "not nice water". I do keep looking for where else it could be coming from other than the black tank. I'm awaiting on the marina to get someone to empty it.
As mentioned in my original post, the inlet from the seacock is not currently connected.

Not giving you a hard time on this, but why are you waiting on the marina to do this? If this had happened to me, I would have immediately driven my boat over to the pump out dock and taken care of it.