Help please...Jabsco wont pump seawater in !

[Baku]

Sorry if this has been asked before.

Our Jabsco 'twist & lock' loo pumps out, but will not pump seawater in.

Have checked the inlet seacock and it is clear.

I have bought a service kit, but before I start, I wondered if anyone might be able to tell me from the symptoms described whether the problem is likely to be at the top of the system or lower down with the joker valve ?

Quite like to avoid taking the whole thing to pieces if I can avoid it.

Any help/guidance/tips greatly appreciated...not really looking forward to this job !

Many thanks,

Giles

 

[Tranona]

Likely to just be the inlet pump. Carefully remove the 4 screws holding the top on and withdraw the plunger. Check the valve. Could also be the flap valve at the bottom stuck partly open. Take care when replacing the screws to give them a little turn anti clockwise until you feel them drop into the thread. Should then run down cleanly without forcing.

 

[rob2]

I have an "ordinary" Jabsco (not twist & lock) which was getting a bit slow to pump. Before getting the service kit, I decided to take a look. It isn't difficult to take the pump off hte base and I found that all the rubber parts in the pump were slimy with some friable hard coating in places. It all wiped off so the valves didn't stick anymore, but when reassembled, it wouldn't pull enough head of water to fill. I unfastened the inlet loop and laid it flat on the floor and bingo - it pumped. Once primed, it hasn't had any further problems.

Beware when reassembling the pump. The screws are self-tappers into a brittle plastic, so it is important to gently wind them anti-clockwise until you feel them drop into their existing cut threads. Tighten gently, with just a squeeze to snug them down onto the rubber gasket/valve plate.

Incidentally, the joker valve is on the outlet side, so not the fault you are looking for. More likely that the flap valve in the base of the pump is sticking - but the joker valve is right next to it, so give it a clean whilst you're in there. A screwdriver, a pair of Marigolds, a bucket with some water and washing up liquid and some kitchen roll should be all you need (hopefully).

Rob.

 

[prv]

Not sure why people are suggesting the valve at the bottom. That's strictly outlet side, which you say is working. All the inlet gubbins are at the top of the pump. I'd take the top off and check that all the little flaps, springs and weights are in their proper places.

Pete

 

[Sandyman]

Unless you have as filter your HEADS inlet could just be blocked with seaweed. Had it happen a couple of times.

 

[johnalison]

It could be blocked but after a period of disuse the weighted flap in the valve sometimes won't settle down to seal the hole. You might find that it will work with some vigorous pumping or that it can be persuaded back if you strip it. It won't misbehave if you leave it in the "wet" position.

 

[Baku]

Thank you for the advice guys.

I am going to have a go at this tomorrow.

Will check the inlet for seaweed first and then, if no joy, service the top part of the system.

Not sure if the service kit includes any lubricant, if not, any pros/cons between vaseline and white marine grease ?

Many thanks,

Giles

 

[Stemar]

Thank you for the advice guys.

I am going to have a go at this tomorrow.

Will check the inlet for seaweed first and then, if no joy, service the top part of the system.

Not sure if the service kit includes any lubricant, if not, any pros/cons between vaseline and white marine grease ?

Many thanks,

Giles

The bits are IIRC, an ordinary rubber, so may not appreciate grease. Vaseline may be OK, but I've always used ordinary vegetable oil from the galley.

 

[l'escargot]

I have known the circlip that holds the little weight on the flapper valve to rust and the weight drop off causing loss of intake water. Otherwise you might just find it perished or scaled up.

I actually find it easier to unscrew the whole pump assembly to dismantle it and work on it on a bench/table rather than kneeling headfirst in a toilet compartment and I always reassemble the lot using copious amounts of Vaseline - on both sides of the plunger and the self tapping screws as well - although I am sure someone will be along shortly to tell you why you shouldn't use it...

 

[prv]

The bits are IIRC, an ordinary rubber, so may not appreciate grease. Vaseline may be OK

Vaseline definitely eats at least some rubbers. In fact, didn't they teach you exactly that in sex ed lessons?

I once made a pair of wooden models of the human arm, with a ball and socket shoulder joint (the ball was a staircase bannister finial from B&Q!). The "ligaments" in the shoulder joint were strips of rubber cut from old bike inner tubes, and the first arm I made was copiously lubricated with vaseline. Halfway through the first day of use, I was called down to help because the rubber was completely disintegrating and the arm becoming impossible for the kids to move by remote control. I remembered those lessons about condoms and lubricant, cleaned off all the vaseline and fitted new rubber strips, which lasted to the end of the week and beyond. The second arm, which I had never got around to greasing, lasted fine with its original "ligaments".

On rubber diving kit, we used to use silicone grease. I think this is what the Jabsco pumps come lubricated with when bought new.

Pete

 

[Vara]

Go along with Escargot, much easier to dismount the pump and work on it comfortably, I use silicone grease rather than Vaseline but I can't imagine that it's an issue of great import.

I have found that on the twist and lock, you can remove the piston without touching the four screws, a smear of silicone grease once a month keeps the pumping easy.

 

[AngusMcDoon]

Common problem if the select lever is left in the dry position. Before stripping, try shifting the lever to the wet position, go away for an hour or too, and try again. This is usually enough for the rubbery bit to revert to its proper shape and for it to work again.

 

[Leighb]

Vaseline is the lubricant specified by Jabsco in their instructions, so should be fine, it is certainly what I use. It can be bought in a usefully small tub. Marine grease tends to come in large tins.

 

[l'escargot]

Vaseline definitely eats at least some rubbers. In fact, didn't they teach you exactly that in sex ed lessons? ...

Looks like Jabsco use different rubber then and we didn't cover marine toilets in sex ed lessons when I went to school...

From the manual here: http://www.sv-zanshin.com/manuals/jabscotoilet.pdf

"...Reassemble the pump as follows:

Push on the new O-ring (key 30) and lubricate with petroleum jelly (Vaseline).

Following the SERVICING INSTRUCTIONS for SEAL REPLACEMENT fit the new seal assembly (key 18), the piston assembly (key 29) and the handle (key 17). Lubricate pump cylinder bore with petroleum jelly (Vaseline)..."

 

[pmagowan]

Yes, this seems to happen when people don't read the instructions and pump away even though there is resistance with the switch in the wrong position. It normally can be sorted out with various permutations of switching things etc as advised but without dismantling (at least in my case this worked).

 

[prv]

I have found that on the twist and lock, you can remove the piston without touching the four screws, a smear of silicone grease once a month keeps the pumping easy.

You can do it on the standard model before the twist-and-lock, too. It's only the really ancient ones that can't.

(For those who didn't realise, there are a couple of flats on the sides of the protrusion that the handle rod comes out of, you can put a spanner on this and unscrew it, then the handle, rod, seal, and piston all slide out upwards as a unit.)

Pete

 

[prv]

we didn't cover marine toilets in sex ed lessons when I went to school...

No, but I hope they covered "rubbers"

lubricate with petroleum jelly (Vaseline).

OK, that's good to know. Plenty of rubber substances are fine with petroleum products - look at all the rubber fuel hoses for example - but some aren't and it's always best to be a little cautious.

Pete