Jabsco Won't Pump Empty

[Herbseesmoore]

today is not my day and tomorrow isn't looking good either.

I'm sure this has been answered before..................
When pumping, after 6 or so the handle will not go down and if forced it will rise to the full out. Fluid level drops in bowl 1" and later comes back up and pressure is off handle. Have determined the vent line is clear.

Where to next? the internal workings of the Jabsco, valves, seals, joker, o rings or should I look to an obstructed hose to the holding tank.


In the week leading up to this wonderful event, there was a high pitched whine, sounded like air getting pressured. May not be related.

[cabo_sailor]

If you are pumping into a holding tank, the tank may be full. I'd also check the valve positions to see just where you are trying to pump.

Rich

[stevensuf]

sounds like a jam on the outlet side? seacock closed or blocked? had something similar before and was a blockage on the outlet side, does it pump water in when you switch over to inlet?

[Herbseesmoore]

pumping to holding tank, which is nearly full, took the deck cover off the pump out hose to assure some where to travel while investigating vent hose.

[stevensuf]

get the holding tank emptied and try again ,see what happens, maybe the back pressure of the near full tank making it nigh impossible to pump forward, failing that a blockage between the pipes from toilet to tank, if its holding pressure ie getting stiff then most likely the mechanism is working ok.

[svHyLyte]

Screeching noise--sounds like an obstructed holding tank vent. (Mud-wasps love the things.) Check and if obstructed, clean it out an stick a cone of nylon screen mesh into the thru-hull end to discourage the critters. A periodic spray with Off helps.

FWIW...

[doug86]

check the hose between the head and the holding tank next. Most likely place for a jamb.

[Hannah on 'Rita T']

And, wait 24 hours. Jams caused by flushed material will break up on their own, unless someone has flushed something naughty.

[DeepFrz]

And DON'T put a screen in the vent line. Flush the vent line out regularly with a high pressure hose to get rid of any mud wasps. There are plenty of posts on the forum about not putting a screen in the vent line.

[peghall]

How far did you go, what exactly did you check, to determine that the vent is clear. 'Cuz I don't think it is, but I need to know where else to tell you to check.

There are other good possibilities...a y-valve that looks open, but isn't...and a VERY common problem in Jabsco toilets: a failed wet/dry cam.

Due to a tooling or production flaw, the d'd thing has a nasty tendency to hang up...and when it does, it creates exactly the kind of back pressure you describe. Try jiggling the lever...that MAY free it, but it's only temporary fix...you can't go on jiggling it forever, and besides...sooner or later it won't work any more. The only real cure is to replace the wet/dry cam assembly....or better yet, replace the whole toilet with a better quality one.

[Herbseesmoore]

Thanks to all. Oh the dread, as I sit here with my coffee, trying to screw my courage up. Got the repair kit and a back up system in the form of a 5 gallon buck and a toilet seat.

I disconnected the vent at the tank and the hull and air passes freely.

I'm all for waiting another 24 hours, but actually waited 2 weeks from the event and am now back on the boat, nothing is dissolving.

I'm really leaning to the wet dry cam and will start my disassembly there.
Peggie, are you speaking of a y valve in the wet dry switch or on the pump out side of the holding tank.

Yes thats the ticket, will attack/fix the wet/dry mechanism.

But first a little rum in the coffee couldn't hurt, could it.

[High Heels]

A little rum in the coffee...nose plug, goggles, and gloves up to your elbows too...

Good luck and report back so we know you survived ;0) Godspeed....

[peghall]

Peggie, are you speaking of a y valve in the wet dry switch or on the pump out side of the holding tank?

No...I'm referring to part #20 in the exploded drawing of the Jabsco toilet pump on the last page of the manual...see it here: Jabsco manual toilet instructions The wet/dry lever (part #23) moves it to block or unblock the flow of incoming flush water when the toilet is pumped. Just WHY it creates a feeling of backpressure when that cam hangs up is something I can't quite figure out...I only know it that when it does hang up, it almost always does so in the dry position and that creates difficulty in pumping that misleads owners into thinking it's a clog or a blocked tank vent.

That part is not in the rebuild kit, btw. You'll have to call Jabsco to get one.

[Herbseesmoore]

Thanks Peggie,
I'm taking it apart very soon, my best guess from everyones input, it will be the wet dry not working properly. Will share results later today.

[US1Fountain]

My boat had the same toilet and I have ran across the same condition a couple times, felt like I was pumping against a closed hose. In my situation, I always found if I didn't flip the lever fully, it would do as you described. Just a tiny bit shy from the fully switched position was enough to cause a back pressure at handle when pumping and not allow me to pump out the toilet contents.