Replacing Jabsco Joker Valve

I'm surprised no one has said to wear marigolds when you're doing it.
The video says it all really but don't overtighten the screws which go into plastic.
 
ghostlymoron said:
The video says it all really but don't overtighten the screws which go into plastic.
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Also it's worth highlighting the screen message that popped-up during the video saying 'try to find the original threads in the plastic'.
Either start the screws carefully by hand or turn them anti-clockwise until you feel them click into the existing thread. If you feel any resistance you're probably cutting a new thread which can only be done a couple of times, so back the screw out and try again.
 
houldsworth said:
not quite sure what you mean by the 'flap valve at bottom of cylinder'.
looking at parts list diagram on web jabscoshop.com it is not clear to me which this valve is!
joker valve is clearly named.
boat in Poros, me in UK at present so can't tinker easily.
Charles

ps. all comments most helpful and appreciated.
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I was talking about the twist and lock model which has a valve at base of the cylinder. No need to touch the connection for the joker valve when replacing this flap valve. You just remove the 4 screws at base of the pump and flap valve sits underneath.

The video link provided by l'escargot shows a twist and lock model. Unfortunately, Wifi is slow today so I didn't look at it to see if the flap valve is mentioned.

I have to agree with Vyv about head of liquid sealing the joker valve. However, they do still tend to leak after some time in use (even when no calcification). The lower flap valve provides a positive seal but the plunger does push a dent in it after a while and you get backflow again.

I change the flap valve on mine when it start to leak back. Easy job and has needed to be done every 2 years or so.

Not much help if you don't have the twist and lock model.
 
pvb said:
I'm afraid that's not true. My Jabsco pumps uphill about a metre to the top of the holding tank, and I don't get backflow at all.
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I can also confirm that backflow has been solved for 6 months after replacing the joker valve on my pre twist & lock Jabsco toilet.

Re. the daylight visible through the replacement valve fresh out of the maintenance kit, any head of water behind the installed valve will tend to clamp it shut.
 
Resolution said:
Did mine last month, for only the second time in ten years. Obviously one should flush through lots and lots of water first, so the pipe post joker contains essentially just water and not gloop. Then have bucket and sponge ready to mop up the spillage quickly. I took three goes to get the new joker to seat itself perfectly with no leakage, so had to go through the whole process too often! All this in full Med heat, dripping with sweat, glasses fogged up, and usual impossible access requiring chimpanzee arms and fingers!! Next time will be quicker.

The old engineers trick before starting jobs like this was to stuff a smear of Vick or Tigers Balm up each nostril.
Peter
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Strange thing about Tiger Balm is that if you add all the percentages of constituents on the label you get something approaching 108% ! (At least it did back in 1990)
 
Spirit of Glenans said:
I would agree with that but would add that it's preferable not to mop up with a dishcloth:)
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Dont you use old dishcloths in the heads when they've become a bit too grotty to use for the dishes.

The 3rd and final stage in their life cycle is is in the engine room for mopping up small oil spills etc.
 
VicS said:
Dont you use old dishcloths in the heads when they've become a bit too grotty to use for the dishes.

The 3rd and final stage in their life cycle is is in the engine room for mopping up small oil spills etc.
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I have a brother in-law that numbers his undershirts according to condition and usage catagory. A little OCD? Nice guy.
 
pvb said:
I'm afraid that's not true. My Jabsco pumps uphill about a metre to the top of the holding tank, and I don't get backflow at all.
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I think that you (and Vyv Cox) must be lucky. I have two Jabsco heads, both are fresh water flushed, and have a holding tank head of well over one metre above them. After meticulous cleaning and replacement of flapvale and joker valve I am lucky if I can get two weeks use out of either of them before they start to backfill again. Quite often they backfill after first use. The forward heads get more use and are the worse of the two. Robin appears to have done the modification I am about to try. I am impressed with the Tru Design sea cocks I fitted 18 months ago and contacted the company in New Zealand about their non return valves, which are spring loaded but not as strongly as some, and asked about use for waste. They replied that they do not recommend them for such use but kindly sent me two to try and I am going to install the first one in September. I will be single handed sailing for over a month and should be able to give it good test as I am going to install it without changing the existing joker and flap valves which are leaking.
 
Norman_E said:
I think that you (and Vyv Cox) must be lucky. I have two Jabsco heads, both are fresh water flushed, and have a holding tank head of well over one metre above them. After meticulous cleaning and replacement of flapvale and joker valve I am lucky if I can get two weeks use out of either of them before they start to backfill again. Quite often they backfill after first use. The forward heads get more use and are the worse of the two. Robin appears to have done the modification I am about to try. I am impressed with the Tru Design sea cocks I fitted 18 months ago and contacted the company in New Zealand about their non return valves, which are spring loaded but not as strongly as some, and asked about use for waste. They replied that they do not recommend them for such use but kindly sent me two to try and I am going to install the first one in September. I will be single handed sailing for over a month and should be able to give it good test as I am going to install it without changing the existing joker and flap valves which are leaking.
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Ours was USA supplied of course and I believe DometiQ brand ones
 
houldsworth said:
Got to replace this valve as loo keeps backfilling.
Presumably as you undo the outlet fitting with joker valve in it the dirty water floods back down the pipe all over the floor as you cant easily get a bucket under it!
Any tips?
Charles
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In my Bene, what little bit comes out goes in to the shower tray, we have shower toilet pods, self contained. Easy to clean after. By the way, the joker valve, just clean it with vinegar and water and re install, the culprit will be the flat flap valve at the bottom of the pump! They distort! Guess how I know!
Stu
 
VicS said:
Dont you use old dishcloths in the heads when they've become a bit too grotty to use for the dishes.

The 3rd and final stage in their life cycle is is in the engine room for mopping up small oil spills etc.
Click to expand...
A big plus one!
S
 
I have a vacuum pump used to extract oil from the sump, I drain the bowl using this and end up with very little "waste" to mop up (with an old dishcloth on its way to the engine bay) - but I will try the al-foil idea. I replaced my old jabsco with the twist lock model with no improvement, one joker valve every year seems to be the go - but I will try the vinegar trick on the one I just removed and see how that goes next time. The old valve has a curve in each "fin", and a visible air gap, compared to straight with no air gap in the replacement. I think this topic comes third after anchoring and flag ettique :-)
 
I don't see how a holding tank can create a 'head' of pressure as surely the pipe from the toilet goes to the top of the holding tank. There should be no more pressure than if the tube went to a siphon break, as only the tube will have liquid in it. I can see it would be a problem if the pipe from the toilet went into the bottom of the holding tank, but that's not the recommended way of plumbing a holding tank.
 
neil1967 said:
I don't see how a holding tank can create a 'head' of pressure as surely the pipe from the toilet goes to the top of the holding tank. There should be no more pressure than if the tube went to a siphon break, as only the tube will have liquid in it. I can see it would be a problem if the pipe from the toilet went into the bottom of the holding tank, but that's not the recommended way of plumbing a holding tank.
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It doesn't make any real difference - the head of liquid is about the same.
 
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