Jabsco Twist & Lock Heads Problem

RichardTaylor

RichardTaylor

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I have a problem with the heads on our 18 month old boat. I thought it was an outlet blockage but proved today this is fine.

Basically with the switch left (raw water in and out) everything seems to pump fine, with the bowl also filling (but was not convinced pumping out). Move the switch to the right (water out only) and I get a back pressure which then can "stutter" the handle as the pressure is released momentarily.

I now know if I have both the raw water inlet and outlet pipe disconnected I pump out fine without any problems, so it seems to be related to the inlet water hoses?

I have an anti-syphon on the raw water inlet (between the pump and the bowl). What I can not determine is whether the problem is in the pump handle mechanism or the anti-syphon.

Anyone had similar experiences or offer any advice?

Thanks
 
Yes have had this problem. Found it was due to the switch not holding over fully to the right though it appears to be correct.
If I remember there is a small spring underneath which gets dislodged.
 
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With Jabscos I found that once the top or bottom sets of self tapping screws had been removed once, the pump was never the same. Cheaper overall, and less hassle, to buy a new pump unit - £60 or so last time I looked..... A few years ago, so probably double that now :(
 
Richard10002 said:
With Jabscos I found that once the top or bottom sets of self tapping screws had been removed once, the pump was never the same. Cheaper overall, and less hassle, to buy a new pump unit - £60 or so last time I looked..... A few years ago, so probably double that now :(
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Or do what I did: bought a complete unit for under £100, then sold the bowl on eBay. I now have a complete pump, plus seat and lid.
 
Not sure what you are doing with the screws. We have two Jabsco loos on out boat and they have both been dismantled a few times without any problem at all. Several times its been for bits of twig and detritus being sucked up the intake and getting lodged in the valves.

The valves certainly work better when they are clean and one of them needs the little coil spring to make it work properly.
 
john_morris_uk said:
Not sure what you are doing with the screws. We have two Jabsco loos on out boat and they have both been dismantled a few times without any problem at all. Several times its been for bits of twig and detritus being sucked up the intake and getting lodged in the valves.

The valves certainly work better when they are clean and one of them needs the little coil spring to make it work properly.
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+1 Thing is with the screws is not to treat them like self tappers and force them in. They are a semi machined fit and if treated with care can be re assembled loads of times.
 
Hadenough said:
+1 Thing is with the screws is not to treat them like self tappers and force them in. They are a semi machined fit and if treated with care can be re assembled loads of times.
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When refitting, rotate the screws backward slightly until they drop into the previous thread, then do up, don't overtighten.
 
They do seem to be problematic and when servicing when you only need a couple of bits you have to buy a whole bag load of spares. As said it seems easier to put a new one in half the time.:rolleyes:

Isn't there a better make than Jabasco, i have to service or replace mine soon and would rather go with something more reliable and easier to gets parts for separately!
 
Zagato said:
Isn't there a better make than Jabasco, i have to service or replace mine soon and would rather go with something more reliable and easier to gets parts for separately!
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The only one I would call "better" is the Lavac. That has only one moving part, the diaphragm in the separate bilge-type pump that empties it. It does also have the seals on the seat which presumably need replacing from time to time; don't know how often.

I don't know what they're charging for it these days, but I suspect you could buy several Jabscos for the same price :)

Or there's the Baby Blake if you want to spend four grand :D

Pete
 
Zagato said:
They do seem to be problematic and when servicing when you only need a couple of bits you have to buy a whole bag load of spares.
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I think that's the choice of chandlers.
On the web you can get just about any part individually, and my local chandler (SMR Brighton) has many bits inc. the weighted diaphragm, not just full overhaul kits.
 
Richard10002 said:
With Jabscos I found that once the top or bottom sets of self tapping screws had been removed once, the pump was never the same. Cheaper overall, and less hassle, to buy a new pump unit - £60 or so last time I looked..... A few years ago, so probably double that now :(
Click to expand...

I think some service kits had screws that were fractionally too long.
 
Stork_III said:
When refitting, rotate the screws backward slightly until they drop into the previous thread, then do up, don't overtighten.
Click to expand...
You have to rotate them backwards a few times until you find the thread they drop into the best, because the screws have twin threads with different depths. It is almost as if Jabsco have designed this to guarantee that eventually you screw this up so much that you have to buy a complete new pump.
 
prv said:
The only one I would call "better" is the Lavac. That has only one moving part, the diaphragm in the separate bilge-type pump that empties it. It does also have the seals on the seat which presumably need replacing from time to time; don't know how often.


Pete
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My lavac is older than I am and as far as I know the seals on the seat have never been changed. Truth be told I can't remember when the pump was last disassembled either. Must be well over a decade. Oh well, while it's not broke, I ain't touching it!
 
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