Having suffered a badly leaking needle valve, easily solved by a new replacement, I find that after shutting down, the Carb drips fuel of a few moments. Can anybody suggests a likely cause? Harry Fox

Location: High Wycome

Location: Near M1 Motorway, Jtn 28

I expect the fuel level in the float chamber is too high. Excess fuel then runs into the inlet tract.
Fitting a new valve probably alters the level.

Location: Melrose, Scottish Borders

Hi Brian, It is a Zenith VA26. I should have said that when I made the query ! Harry

Location: High Wycome

Hi Harry, it could well be a high fuel level as Jim suggests or, if it only happens with a hot engine shut down after a run, it could be "heat soak" raising the temperature of fuel in the pump, pump to carb. fuel line, and float chamber. This causes the fuel to expand and can, if enough heat, cause percolation or fuel boiling in some or all of these components. This will cause fuel to drip from either/or the float chamber vent, the open mouth of the atmosphere side of the carb.

Ian Mc.

Location: Shropshire

That, Ian is one thing that I would never have thought of ! yes, it was hot, Thanks, I will run it when cold tomorrow, switch off quickly and check. Thanks again, what a wonderful thing this Forum is.,apart from the fact that I never seem to type the code correctly to get the post sent !
Harry

Location: High Wycome

Brian Jim and Ian, Thanks for your suggestions re dripping carb. I checked that it wasn't heat build up, I started it from cold, ran it for any a few minutes, switched off, and it dripped. I then put another washer under the Needle valve (more that two would not leave enough thread) it started immediately, ran well but after shutting down it dripped for about 5 minutes. I had another run and this time collected the drips which amounted to a tablespoonful? Any other suggestions? Harry

Location: High Wycome

It is usually what the others have said, in-particular too high a fuel level in the float chamber. Are you sure the extra washer hasn't made that worse? You need to lower the fuel level in the float chamber. I cant picture the workings of the Zenith, but on an SU I would very carefully bend down the little brass lever between the float and the needle. About 1/16" is usually plenty.

Location: Devon

Another thought..

the needle goes straight onto the top of the float on the Zenith doesnt it? So the washer should have had an effect. I wonder if your new needle is seating properly? If its marginal then the inherent pressure in the system could be overcoming the valve and causing an overflow.

Try turning the valve hard against its seat with your fingers, effectively lapping it in without any grinding paste. Check the float isn't punctured and floating low due to fuel inside it. If that doesn't work the needle and seat will have to be lapped together properly.

Location: Devon

Harry, make sure that the gasket between the float chamber and the emulsion block is undamaged and the emulsion block screwed up securely.
Probably won't help with this problem but I am PM ing you a pdf data sheet for the 26VA that might come in useful sooner or later.

Ian Mc.

Location: Shropshire

Hi Stuart, On the zenith, it isn't possible to do much with the needle valve it is made in three parts parts, then assembled in such a way that they can't be opened, and, so little of the needle is showing that it is almost impossible the twist it around. I have removed the bowl very gently straight after shut down, and the fuel level isn't high. Of course, the float has been checked. When it gets solved, I will put it on the forum. I only hope it will be soon! This is the reason we have these old cars, better than doing crosswords! Harry

Location: High Wycome

Ian, I am coming to that conclusion too ! Harry

Location: High Wycome

Good evening all.
I await a definitive solution to this problem as it's been troubling me for the last 40 years! I have rebuilt many 26VA's and some leak when on test with a pump (no engine/heat involved).
The only solution I have found is to experiment with alternative float chambers but why this should work I don't know. The modern replacement needle valves I have found to be too long.
One tip I was given some time ago was to match the correct type of float chamber with the body i.e. if the body has two 'tubes' adjacent to the mixture screw the float chamber should have two exposed 'tubes' underneath. If the body has one exposed 'tube' then the float chamber is deeper with no exposed 'tubes'.
Hope this helps
Regards
Stuart

Location: The creative county, Staffordshire

To all who have sent suggestions, I haven't been able to tackle the problem today, sometimes the Austin has to take second place, but I will be back on it tomorrow when another Needle valve should arrive (being new doesn't always mean that it is ok) but one suggestion that I am going to try is to put the bowl in upside down !!! Harry

Location: High Wycome

I said bowl, of course I meant Float!!!! Harry

Location: High Wycome

To end this discussion on a leaking 26VA Zenith carburettal, the solution turned out to be the NEW Needle valve was faulty, a new,new one solved the problem. Proving the point that because a part is new, it doesn't mean it is ok ! Harry

Location: High Wycome

Please can anyone advise where to buy new needle valve for zenith 26VA

Thanks : Bruce

Bruce, you can obtain one of these from Rimmer Bros Triumph and Austin Rover stockists telephone 01522 412 500 - I know because I bought one today as Burlens have no stock! They sold all 40 off to Rimmer Bros yesterday!!

Location: staffs

Bryan,
Thanks for your advise
Regards : Bruce

Hiya.

I'm also looking for the said needle valve. I just spoke to Rimmer Brothers & they have no idea what part it is. They reckon it must be the same as on a triumph stromberg & will only have it as one of their part numbers.
Do you know what part number you ordered from them?

Regards Ed

Location: North Wales

They say things happen in threes , well Harry and Ed , I just made it into third place.
My VA 26 started pouring fuel out of the breather vent as I was checking "Annie" over for tomorrows Drive it day. I stripped the carb and tested the needle valve but all seemed ok. Connecting the body to the fuel supply in an inverted state, it allowed me to watch where the leakage was occurring. With the needle valve closed by light finger pressure I found the fuel was by-passing the valve and leaking passed the sealing washer.Right thought I , replace the washer. Still leaking. I tinned the washer and voila sealed.Whilst the iron was hot as it were I tinned the worn float top where the needle valve sits , this should help as I felt the float level was always a bit high.

Location: Piddle Valley