Carb help

[Steve Jones]

@Steve: I'll send you a PM with my address etc. The hole does not have any thread. Its about 8mm in diameter, but then about 11mm down into the hole there is a step to a narrower diameter (guess about 5mm). So I wonder if your two part tubes and caps will work ? Judging by the markings inside the hole, it looks like it could have been in two parts. About 3mm down, there is a very slight indentation as if the tube or cap had a very thin O-ring but with the cap simply jammed/wedged in ?  Looking at my rough diagram, does it feel as if the bits you have will fit ?

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My parts won't help you Richard. If the drilling doesn't have an internal thread then it's not meant to have anything in it. 

The first picture is a scan from a 4th edition of 'Nicholson' (1933) showing the float chamber at that time. You can see the cap over what is called the 'Compensating Well'. This has the brass tube beneath it. 

   


The second picture is a scan of the similar page from the 6th edition (1937) that shows what has now become the 'Capacity Well' and is just a drilling in the float chamber. This is as the picture of your float chamber in your original post. 

   

I still think your problem is one of a fuel level that is too high either because of its setting or something stopping the needle valve fully closing.

Steve

[e-richard]

Steve, thanks for all the effort and research.  I now think that Derek Simmonds is probably on the right track.

When I empty the carb bowl, there are always tiny bits lying around.
I have replaced the fuel pump with a brand new one and just checked. Hey presto the filter gauze inside the pump is still in pristine condition.
So one has to wonder where the gunge is coming from?
I'm hoping its somewhere between the pump and the carb inlet - or maybe even inside the carb itself?

So, a very thorough clean of the carb and inlet filter is called for. 

I'll report back if/when there is any progress

Can one put an inline paper filter between pump and carb ?

["Slack Alice" Simon]

One of those bowls is for a side draft carb, the other is (?) downdraft.

I like the occasional debris solution, my tank is a bit rough inside.

I took a tea cup full of big debris out, I clean the pump and banjo filters, but the bowl has a layer of very fine dust in the bottom every time I look in it.

This over about 500 miles.

I think it will clear, in time.

Simon

[Derek Simmons]

Yes Richard, you can put an inline fuel filter after the pump but the thinking of the A7OC member who suggested it to me was that by putting it before the pump meant one did not need to take the dome cover off the pump very often thereby protecting the screw thread of it! Logical thinking?? I located my inline fuel filter in a position where I can easily change it quickly on an annual basis! Because they're so cheap I have got next years already!

[Ian McGowan]

e-Richard, despite advice to the contrary, the attached data sheet for the A7 version of the Zenith 26VA clearly says that in the 26VA carb. the capacity well is cored the required size and therefore no capacity tube is required.

Ian Mc.


  Zenith 26VA Carb.pdf (Size: 277.72 KB / Downloads: 1,186)

[Colin Reed]

Hi All,
         What does help with the rubbish coming from the Tank is a product called POR15
         This is a tank sealer and is available as a kit from www.frost.co.uk
         Have used this product on a lot of old tanks and it does work very well,
         you have to remove tank from car
         one thing you have to watch is to plug any threaded holes or you will have to tap them out after as it does go
         hard will also fill small holes.
        
          It will save Breakdowns because of dirt

Happy Motoring