Manual Black Water Pump

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Nick
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Manual Black Water Pump

Post by Nick »

Seems the manual black water pump is a pretty easy principle. Mine has worked fine to date, but recently seems to have stopped pumping. I disconnected the black water hose to check incoming pressure and it seems to draw although not sure what “normal” is. I suppose next step is to disassemble the pump itself, but am I missing something? Seems like too easy a system to have a major fail unless a diaphragm, but like I said it sucks. Does anyone know the manufacturer name?

I am in the Bahamas and left the black water valve open....is it possible the tank would have been sucked out while underway? Any guidance would be much appreciated
Nick & Barb
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duetto
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Re: Manual Black Water Pump

Post by duetto »

hi nick,

not sure if a vacuum would empty tank. can you tell if tank has stuff in it?

also, not sure which pump you have. our overboard out of the tank went thru a jabsco electric macerator.

that said, i'm familiar with 2 different diaphragm pumps (similar to a whale). both are round, where the diaphragm sits, and both have an inlet valve and an outlet valve out of that chamber. here are the things which over the years made them either stop pumping or pump inefficiently: 1) someting is keeping the inlet valve from closing (i.e. toilet paper, crap buildup,...) actually same would be true with outlet valve. 2) if diaphragm is rubber, buildup of crap is preventing it from deflecting to cause a vacuum.

when i had trouble when in marina i got some muriatic acid and put pump parts in bucket for an hour. this will make them serviceable but not new. in a pinch just scrape the buildup off the parts.
john & diane cummings
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Nick
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Re: Manual Black Water Pump

Post by Nick »

Thanks duetto for quick response. Well, I'm assuming the tank has stuff in it because we've been putting "stuff" in there (although never toilet paper). I turned the valve to pump out overboard as we left Florida and successfully pumped out (wasn't much) and then left that valve open assuming it was unnecessary to close once off shore. Normally, there's a pretty "solid" feel to the pump once it's built pressure and starts to draw material up the hose. I now get a gurgling when pumping, but nothing actually comes out. That's what led me to think pressure may have drawn material out as we were underway. I disconnected tank side of hose from pump to check if I was getting suction when pumping. I am, but not clear it's enough to draw material up that hose and out.

Yes, the pump is a manual pump with a "collar" like the Whale Pump in shower. Next step will be to disassemble and clean as you suggest...oh boy! Why does this stuff happen at the most inconvenient times in the most remote locations???? That's boatin" I guess. Thanks again for the help.
Nick & Barb
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duetto
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Re: Manual Black Water Pump

Post by duetto »

nick,

if it's not too big a deal, try hooking up pump to a bucket of water and see if it'll empty it. if it does, i'd be looking for a blockage or maybe a plugged vent hose. if it doesn't, start taking it apart.

where are you in bahamas?
john & diane cummings
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Nick
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Re: Manual Black Water Pump

Post by Nick »

Will try the water test first as you suggest. We’re at Staniel Cay right now and believe it or not found a random guy at some storage locker who had some muratic acid! Will update on result(s).
Nick & Barb
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duetto
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Re: Manual Black Water Pump

Post by duetto »

nick,

when you get back get a spare set of whatever valves are on the inlet and outlet of your pump.

good luck.
john & diane cummings
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kjoverbeck
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Re: Manual Black Water Pump

Post by kjoverbeck »

Nick, I had that pump installed just before our Bahamas trip in the Spring 0f 2017. You are the first to use it so I doubt buildup is the problem. Since pump out worked it doesn't sound like blockage in the tank. My bet is on a valve stuck open in the pump.
Good Luck Buddy, Kent
Nick
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Re: Manual Black Water Pump

Post by Nick »

EPILOGUE: I took the pump apart (very simple and not gross!) and found some hard piece of crud stopping the joker valve from closing thereby limiting suction. Figure the crud somehow broke loose during rough passage (there have been a few this year in Bahamas). Anyway, cleaned it up and pumping strong! Onward! Thank you.
Nick & Barb
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Re: Manual Black Water Pump

Post by kjoverbeck »

Happy Easter!!!
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Re: Manual Black Water Pump

Post by duetto »

so nick,

what kind of pump is it?
john & diane cummings
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Nick
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Re: Manual Black Water Pump

Post by Nick »

It’s a manual Whale Pump mounted under deck in front of starboard hatch. With only one moving part (beside flapper and joker valves) and no electric component it is very simple and normally very reliable. Thankfully access and repair was easy once you put me on the right track!
Nick & Barb
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