Crappy situation part 2. You won't believe this!

family affair

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You all might have seen my 2 other posts about my holding tank and head. Every time I think I have it fixed, I find out I don't. I finally pulled the floor up. I pulled the tank sensor out and the tank was 100% full despite pumping it out a week ago! Yamaha's make oil, my holding tank makes black water. Awesome.
My only thought was that somehow the suction tube broke or rotted off and pump outs were only pulling water off the top. I decided to pull the pump out hose off and found this:
20240811_161350.jpg

Grady rigged the damn tank wrong from the factory! 19 years and no one knew.
20240811_162614.jpg

Ive never been so excited to have my holding tank pumped out!
 
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Hookup1

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Worst project in boating. Unfortunately I have earned my PhD in MSD's working on my CPU (Crap Processing Unit). I'm not sure if this is OEM. The Groco phenolic plate and plumbing looks standard. The Shurflow pump doesn't - maybe it has nothing to do with pumping the head out - maybe an owner modification. Normally these Groco setups have a in-tank macerator that works pretty well until it doesn't. Expensive to replace. I re-designed mine -seems to work. I don't understand that Blaster pump being there...may have nothing to do with holding tank.
 

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The blaster pump is for fresh water. It has nothing to do with the waste system.
Once I get this pumped out, I might try to resurrect the groco pump, but odds are it is trashed. It has been marinating in yuk for almost 20 years. If it is indeed not salvageable, I'll consider the options others on the forum have tried.
 

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Grady rigged the damn tank wrong from the factory! 19 years and no one knew.
Why do you think so? Was the hose to the seacock connected to the elbow in you hand?
All the hose elbows are a bit confusing, but i believe that
the one in your hand is unknown as it is going deep what suggest a discharge
the one below, right side is the inlet from toilet bowl

Where does the hose connected to the Waste Discharge Elbow goes?

Yes, for that cost i would probably find a alternative solution, or in case change the holding tank as well.

Ex Owner left me some floatings in the holding tank and i need to discharge that, so hopefully my system works as access don't look so comfortable as in your Islander.
However i am considering to clean the holding tank well and pull the toilet bowl and seal all well as i never use the toilet and could use the space to install a rod holder what would be more useful for me than i toilet bowl i never use.
Chris
Bildschirmfoto 2024-08-12 um 09.58.31.jpg
 

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I share your agony...

A 5 gallon bucket, one third full of seawater, is an elegant alternative.
When finished, put a lid on the bucket as you carry it from downstairs to the rail.
 

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The blaster pump is for fresh water. It has nothing to do with the waste system.
Once I get this pumped out, I might try to resurrect the groco pump, but odds are it is trashed. It has been marinating in yuk for almost 20 years. If it is indeed not salvageable, I'll consider the options others on the forum have tried.
There is a recent thread SkunkBoat has been working on dealing with replacing the Grocco pump. I did mine a few years ago too.
 
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Why do you think so? Was the hose to the seacock connected to the elbow in you hand?
[/ATTACH]
The pump out hose was connected to the inlet and the head hose was connected to the discharge. The tank never emptied because I could only draw water off the top of the tank instead of from the bottom. Also explains why the head would back up.
 
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There is a recent thread SkunkBoat has been working on dealing with replacing the Grocco pump. I did mine a few years ago too.
If anyone can provide the link, please do. There are several out there.
I might make this a winter project including replacing the tank sensor with an external. While I'm at it I can add a freshwater tank sensor too.
 

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If anyone can provide the link, please do. There are several out there.
I might make this a winter project including replacing the tank sensor with an external. While I'm at it I can add a freshwater tank sensor too.
There are several posts. Just search GROCO MACERATOR. Here are two. Nothing works better than a in-tank pump when it's working. Most members switched to standard Jacsco macerator installed above the tank. This pump has to "lift" contents. You have to be careful to avoid air leaks or running the impeller day. Some modifications involved a y-valve.

This is along thread but look around post #33

Look at post #5. I have had problems with impeller running dry. The way the pump sits will drain and I have to pull discharge hose and prime it beginning of season. Look at how others have mounted their pumps.
 
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Sardinia306Canyon

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The pump out hose was connected to the inlet and the head hose was connected to the discharge. The tank never emptied because I could only draw water off the top of the tank instead of from the bottom. Also explains why the head would back up.
Oh, well then someone made a mistake or older owner/s plumbed it differently to dump directly in the sea.
Chris
 

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Success! Pump out and complete evacuation of the system. I actually get clear water out of the holding tank now. Plus, flushing actually results in clean water in the bowl. I never thought a marine toilet could bring so much joy! :)
Now that I can actually have clean water in the bottom of the bowl, what is a proven, safe cleaner and/or sanitizer that won't damage my Jansco electric flush system?
 
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Now that I am familiar with the plumbing, I understand what others have rigged up. I need to make some decisions on what to do with the old Groco and plumbing. If I try to add a Y valve to mine as configured, I'd have a long reach to that valve. I might consider placing the suction tube on the opposite side of the tank, that way I can have the Y valve just under the pie plate.
 

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Now that I am familiar with the plumbing, I understand what others have rigged up. I need to make some decisions on what to do with the old Groco and plumbing. If I try to add a Y valve to mine as configured, I'd have a long reach to that valve. I might consider placing the suction tube on the opposite side of the tank, that way I can have the Y valve just under the pie plate.
I don't have a y-valve on my islander. The tank has a pumpout hose to the deck and a hole in the plate for the Groco pump to overboard discharge. It's a difficult place to work on. You can't get two hands into it and you are working over the bowl. Be careful not exceed your access or physical ability to get in there!

I removed my Groco pump and made a PVC fitting for the tank top to pump. The y-valve shares the deck pumpout connection/hose. Has to be switched to use it. It's also a possible air leak that may affect overboard pumpout. I wouldn't bother.
 

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I don't have a y-valve on my islander. The tank has a pumpout hose to the deck and a hole in the plate for the Groco pump to overboard discharge. It's a difficult place to work on. You can't get two hands into it and you are working over the bowl. Be careful not exceed your access or physical ability to get in there!

I removed my Groco pump and made a PVC fitting for the tank top to pump. The y-valve shares the deck pumpout connection/hose. Has to be switched to use it. It's also a possible air leak that may affect overboard pumpout. I wouldn't bother.
So you're only option to empty the holding tank is to pump it overboard?
When they redesign the islander, the access to the holding tank system is much easier through the hatch at the helm.
 

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So you're only option to empty the holding tank is to pump it overboard?
When they redesign the islander, the access to the holding tank system is much easier through the hatch at the helm.
I think he has a pump out fitting similar to the fuel fittings to get the crap sucked out in a Marina, same as i have.
I have a panel inside the console where i can see the holding tank level and activate the pump to discharge it overboard
Chris
 

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I think he has a pump out fitting similar to the fuel fittings to get the crap sucked out in a Marina, same as i have.
I have a panel inside the console where i can see the holding tank level and activate the pump to discharge it overboard
Chris
From the looks of his shared photos, it appears overboard is the only option.
Since I have another spot on the tank to run another tube, I could do that and have both overboard and pump out without a Y valve... I think.
 

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So you're only option to empty the holding tank is to pump it overboard?
When they redesign the islander, the access to the holding tank system is much easier through the hatch at the helm.
No. I have a factory installed deck fitting/hose connected to the bottom of the holding tank. I use this to pumpout at the marina.

I also have a hose coming out of the holding tank macerator plate on the top of the holding tank . That connects to my overboard discharge hose.

The boats with y-valves switch the connection to the bottom of the holding tank depending on if they are pumping out at the marina or feeding an external macerator pump for overboard discharge.
 
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