Waste mixed with incoming seawater on jabsco manual toilet

[LifesBetterWhenYoureBeating]

Originally Posted by ItDepends

I don't really buy the "manual Jabsco toilets have a short lifespan" story. We have two that have been in liveaboard use for 25 years. Routine maintenance takes place once a year, usually just replacing rubber parts, but isn't that true of EVERY marine toilet? From a cost/benefit standpoint they are pretty damn impressive.

But... to the OP's problem...
He said that he inspected the o-ring on the piston and it looked in good shape. If the o-ring on the piston looks good, it is very hard to imagine how significant mixing of incoming flush water and outgoing waste can be occurring inside the pump.

I am putting ALL my money on the flapper valve at the base of the pump. This must seal for waste to get pushed out through the joker valve and down the the discharge piping. If this flapper leaks, some, most, or all of the waste comes back into the bowl as you press down on the plunger. Sometimes this happens temporarily when a bit of solid waste lodges there, but sometimes these valves get old and tired, and the flap doesn't come down and seal as it should.

Of course this flapper valve is part of the standard rebuild kit, so if you go through that process it will fix your issue.

The flapper valve was indeed deformed. I've replaced it, tested with food coloring and it seems to work fine now. Tomorrow I should have a definite confirmation

[LifesBetterWhenYoureBeating]

Originally Posted by wholybee

Are you discharging into the tank, or overboard? If overboard, the intake could be intaking the just discharged water.
I had to replace my pump as the walls of the pump wear, and a new ring didn't seal. This can be significant if you don't rebuild often, as the buildup can be like a sanding stone.

Into the tank, but the tank discharges overboard directly. It takes more than 10 pumps before I see waste overboard, whereas on the second pump I was already seeing waste mixed with the flush water

[LifesBetterWhenYoureBeating]

Replacing the flapper valve didn't fix it. Maybe the cylinder is worn and the piston is loose inside it?

[gonesail]

waste could be bypassing the piston and being pumped back into the head with the fresh water. did you try a new piston O ring? if you do that be sure to use plenty of silicon grease in the cylinder and the shaft seal at the top

[Searles]

To much back pressure is the main problem ,causing waste to force its way back past the joker valve and or foot valve ,partial blockage of the outlet hoses and or valves is generally the reason for the back flow ,⛵️⚓️

[peghall]

Sea water mineral buildup in the toilet discharge line can create back pressure and is far more common than an actual blockage, but a blocked holding tank vent is the most common reason for waste back flow. When air displaced by incoming flushes can't escape out the vent, the tank--the whole system--becomes pressurized, creating back pressure that prevents flushes from going anywhere but back to the toilet. A seriously pressurized system will result in a geyser when the deck pumpout cap is opened and/or can even erupt in the toilet.


--Peggie

[LifesBetterWhenYoureBeating]

Turns out it was just the piston o ring. The old one looked fine but it looks like it wasn't sealing properly. Once I replaced it the pump started bringing in a lot more flush water on every stroke and I no longer get waste mixed into it

[billdomb]

Prolly a new topic, but haveta recount a story told by the famed Stan Waterman. During the filming of The Deep, he notes that several stars were in the water under the boat when someone flushed the head and turds went past the actors.

I don't know all marine heads, but think this is BS.

[peghall]

And I think you're right. Solid waste--which, btw, is 75% water--is broken up by manual toilet pumps, "pureed" by macerating electric toilets. Someone would have to poop while IN the water with pants down to deliver an intact "baby ruth bar."



--Peggie

[White Rabbit]

Are you sure it's waste? It could be growth inside the hose coming from the thru-hull to the pump. If you don't use it often, you can get foul smelling water and junk growing in the line. I live in Chesapeake Bay where the water is brackish and I have that problem.

[cal40john]

Originally Posted by White Rabbit

Are you sure it's waste? It could be growth inside the hose coming from the thru-hull to the pump. If you don't use it often, you can get foul smelling water and junk growing in the line. I live in Chesapeake Bay where the water is brackish and I have that problem.

See post #22

[chris in SG]

Originally Posted by wholybee

Are you discharging into the tank, or overboard? If overboard, the intake could be intaking the just discharged water.
I had to replace my pump as the walls of the pump wear, and a new ring didn't seal. This can be significant if you don't rebuild often, as the buildup can be like a sanding stone.

Congrats to Wholybee for asking the right question. I would bet that the OP was discharging overboard and the seawater intake is too close to the discharge (as is usual). I would also bet that conditions were calm, with minimal current flowing.

I don't think that changing the piston ring solved the problem, which will occur again randomly in the same sea state.

Incredible that nobody else here has experienced this!

[chris in SG]

Originally Posted by gsalgado

Into the tank, but the tank discharges overboard directly. It takes more than 10 pumps before I see waste overboard, whereas on the second pump I was already seeing waste mixed with the flush water

Apologies, I didn't see this reply..

[Epikur]

Originally Posted by peghall

Jabsco manual toilets have fairly short lifespans, so I'd just replace the pump. I know a number of people who replace it annually as "preventive maintenance." Price is very little more than a "service kit" --you can find the pump for $95 from several retailers, service kit is $89--and removing and replacing 4 bolts and two hoses is a whole bunch easier than taking a pump apart to repair it. You'll also need to replace the joker valve...about $15.


Jabsco Manual Twist & Lock owners manual


--Peggie

I had a "nice" encounter with my Jabsco toilet.
I bought my boat in 2015 an shortly after replaced the manual pump assembly.

This year the pump had a malfunction.
I opened the pump head to check the freshwater valve.

And ALL!! but one of the molded plastic screw threads broke of! The pump was beyond repair.

Thank goodness I kept the old pump somewhere down in the bilge AND found it. To replace the pump I had to take the pump off. Since the valve failed in the middle of the process it was not pleasant. But could be much worse!!!

The valve was blocked by a chunk of corroded green metal. I inspected the inlet and it was in pristine condition. I can only suspect that the metal chunk came from the Jabsco freshwater valve.

The fault was caused by the new Jabsco valve, and the repair was marred by the new Jabsco pump head falling apart.
Without the old part I would have been in deep ****. Quite literally.