Should a Jabsco toilet self prime?

monkfish24

monkfish24

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Stripped the toilet down this winter for a thorough clean out, not the most enviable task obviously but I'm pretty sure I rebuilt it as I found it and in accordance with the book.

Refitted it in the boat but now can't get water through to the bowl, relying on us pouring water down it. The inlet pipe has a large Goosneck, running about 3-4ft higher than the toilet.

Can I prime it in anyway or should I strip and check the Valves?
 
Almost certainly the flap valve on the inlet sicking. Take the top off (the bit with the handle) and check that the flap is not sticking.
 
Tranona said:
Almost certainly the flap valve on the inlet sicking. Take the top off (the bit with the handle) and check that the flap is not sticking.
Click to expand...

+1 if you have changed nothing in the design/pipe routes cocks etc, it will almost certainly be in the valve chamber. Get the tools back out!
 
The inlet pipe has a large Goosneck, running about 3-4ft higher than the toilet.
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mention of anti-syphon loops in the inlet pipe always rings an alarm bell.

The loop, with an antisyphon valve at the highest point, should be between the pump and the bowl , not between the seacock and the pump.
 
monkfish24 said:
Brilliant, thanks guys, will have a look this weekend and hopefully have a happy heads again.
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Be careful when re-assembling. After inserting the screws back into the holes and before screwing them home, back them off until you feel a click. This is the self-tapping screw finding it's previously made thread. Unless you do this, there is a very great danger of the somewhat aggressive screws used, breaking the plastic out around the screw holes as it isn't very durable nor easily capable of making a fresh thread once one has previously been made. The top cover ones are especially prone to this damage and that will mean a new pump body unless you are good at mackeling up a repair.

I agree, your problem is with one of the valves, either the top one or the bottom "flopper". Always worth swapping them all when you have it to bits, including the "Joker", seals too. Worth also, cleaning all the limescale out of the pipes.

Chas
 
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I had this problem and they supplied me with a small spring to ensure the inlet flopper valve stayed raised. Fitting the spring solved the problem.
 
CharlesSwallow,

I don't remember a spring and I've looked at pics of service kits and can't see a spring.

Can you give more info please.
 
VicS said:
The loop, with an antisyphon valve at the highest point, should be between the pump and the bowl , not between the seacock and the pump.
Click to expand...

Forgive me for the temerity to argue with an expert, but surely Jabsco WCs are fitted with a very short pipe (which is not even jubillee clipped) from the top of the pump to the bowl. Why would you want a loop and anti-syphon valve there?
 
The anti syphon loop should be between the pump and bowl if fitted with a valve (leak), otherwise it can be between the seacock and pump.

I rebuilt my Jabsco a couple of times one afternoon before deciding the crude design and manufacture was never going to prime through the anti syphon loop. I unclipped the loop from the bulkhead, laid it on its side to minimise the head of water to pump and away she went. Has not lost prime since and works just as expected.

Rob.
 
davidej said:
Forgive me for the temerity to argue with an expert, but surely Jabsco WCs are fitted with a very short pipe (which is not even jubillee clipped) from the top of the pump to the bowl. Why would you want a loop and anti-syphon valve there?
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That is how they are supplied but that does not give you the protection of an anti-syphon loop. Necessary when installed near or below the water line.

If you fit a loop without a valve it wont function as an anti-syphon loop. It'll syphon water in until the seacock is closed.

If you fit the loop and valve between the seacock and the pump you'll suck air in when attempting to flush!

Therefore if the installation is such that an anti-syphon loop is required it must replace the short connection between the pump and the bowl.

I am not making it up its all pretty simple logic AND it is all described in the installation instructions. q.v.
 
Happened twice to me in 9 seasons. Take the end off the pipe where it fits to the bowl. Hold it vertical. Fill it with water and pump as to fill the bowl. Some water may spray out but it will prime. Fill, lower it down and reconnect. It works. No need to strip it or remove the head. Mine is 9 years old and the boat has done 10,000 miles. I also put vaseline on the piston and shaft twice a season as it significantly reduces the friction.
The cause is the moveable valve has been left in open position for too long. Should be left in fill mode.
 
TonyS said:
Happened twice to me in 9 seasons. Take the end off the pipe where it fits to the bowl. Hold it vertical. Fill it with water and pump as to fill the bowl. Some water may spray out but it will prime. Fill, lower it down and reconnect. It works. No need to strip it or remove the head. Mine is 9 years old and the boat has done 10,000 miles. I also put vaseline on the piston and shaft twice a season as it significantly reduces the friction.
The cause is the moveable valve has been left in open position for too long. Should be left in fill mode.
Click to expand...

Agree with your last sentence.

Chas
 
CharlesSwallow said:
NO. Last two I bought had a spring as does the one I have in stock.

Chas
Click to expand...

Three years ago I rung Jabsco's distributor with complaints of lack of primimg and he prescribed the use of a flopper spring - and he admitted they had stopped routinely supplying the spring following Jabsco's instruction but against the distributors' advice. He said they kept a healthy stock level of them to send out! Instant cure.

Obviously Jabsco have now seen the error of their ways ;)
 
Black Kippper,

Many thanks for that confirmation. I replaced my pump last season and the old one had no such spring. I shall look out for it when I take the top off my new one.
 
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