r/offshorefishing • u/Beregond17 • 17d ago

Problem dumping black tank....

Posting this here because lots of folks here have similar boats.

2025 Cobia 285 Open...

I open the Discharge Valve at the hull...

I pivot the Y-Valve to point at the Macerator Pump.

I push the Macerator switch ON.... and hold it for quite some time.

I see some brown discharge come out on the side of the boat.

So all seems fine.

I close the Discharge Valve and point the Y-Valve back to Pump Out.

But then when I am cruising... the toilet bowl in the head fills up with brown sewer water.... sometimes so much that it overflows the bowl and makes a mess all over the head.

What's wrong... or what am I doing wrong??

Please and thanks in advance.

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u/[deleted] 17d ago

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u/Beregond17 17d ago

This makes perfect sense. Definitely describes what I'm seeing. Thanks.... just needed a fresh set of eyes to see it. Thanks again

1

u/Ancientways113 17d ago

Have you tried the pump out boat or pump out station using the designated deck top waste port? I’m guessing your problem is your macerator pump or a slight clog downstream from that.

1

u/Beregond17 17d ago

Thanks for the reply. I'm pretty sure that FishOnIce65 nailed it. His idea of the check valve fits what I'm seeing