Problem with old Solex carb

Bustamif

Bustamif

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I have started a new thread on this issue although the topic is also on my restoration thread. There is a strange brass fittng that p...sses fuel out when I try to run the engine. Its a 1952 Renault tractor. The offending part is on some type of choke, the brass fitting is open to atmosphere. I have changed the orientation from facing down, front or up but nothing stops it leaking fuel.
It's not a needle and seat issue, it is gravity feed, no fuel pump, it only leaks when the engine runs and it spits fuel out. It looks like a brass jet holder but there is no internal thread. Maybe something is missing ? I have not been able to find any detailed pics of this carb to check if there is some part missing.
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T5.jpg
 
I'll confirm some numbers tomorrow, its an updraft carb, but not a 30 AKV. I'm told it could be same carb on some 1950's Peugeot's ?
 
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As with most Solex carbs the device with lever is an enrichening device for starting as distinct from a choke butterfly.
The brass "jet" on the side may have been fitted by someone in error ?
 
It looks like a 30 AKV.🤷‍♂️
I've added a picture of a 30 AKV (with a Model A Ford adaptor) the jet is orientated opposite to yours?🤷‍♂️
I've also added a chart of the other Solex models and a link to a 30 AKV on-line manual, it's in French though.
Where your jet is; some of the other models seem to have a tube that orientates down.

www.delcampe.net

carburateurs SOLEX vertical - Types 30 AKV - SOLEX Neuilly sur Seine | For sale on Delcampe

Starting at €8.77 - Category: Old Paper > Advertising
www.delcampe.net www.delcampe.net

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2003-02-04 (1).jpg
 
Mine looks similar to the 30 AKV that appears above, and it has "30 AKV" in the bottom casting near the float bowl however check the shape of the top casting on the photos of my carb and you will see its not the same design. The area at the top of my "enrichening device" or starter #503 is much different.

I may have to assume there is some part missing from that brass jet and put some type of breather or tube from the jet back to the inlet side of the carb.

I cannot believe that the design is intended to spray fuel from that jet all over the outside of the carby.

I'm certainly not starting it in the workshop, only a safe area outside with an extinguisher nearby. Probably should wear my fire suit with this thing.
 
Well it has been a looooong time since I worked on a Solex with a bi-starter, or just a single starter unit. But as i remember there is no fuel in that part. The external tube brass fitting or whatever is just to let air in. The rotation of the lever just uncovers and links a primitive air/fuel supply system that will be very rich and on a bi-starter a second position that is not so rich to run on for some short time at closed throttle. These mixtures are supplied by passages in the carby body with calibrated holes or jets and not in the starter unit.
So my suggestion is to look at the float system and the gaskets sealing the fuel and air passages. A positive fuel supply from the tank above might be forcing fuel up from the bowl by one of the passages in the body . ??
Would this help; https://extrudesign.com/solex-carburetor-construction-and-working-principle/
good luck Jaahn
These pics are out of an old book, chapter on carbys. Not an updraft type unfortunately but shows the starter circuit passages.
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I'll have to do more homework. Although the diagram above from Jaahn is different to my carb, it would seem that on my carb there is fuel getting to some place it shouldn't be.
 
Aren't downdraft carbies built the way they as they can push fuel over and drip by design ...... being downdaft means it'll drip on the ground rather than into the motor.
 
I think there's a few reasons for updraughts on tractors.
The exhaust goes up on most tractors so it keeps the carby down out of the way of the heat.
You don't need a fuel pump.
If you forget to turn the fuel tap off you don't end up with 10 gallons of fuel in the sump.
The lower position means it is less likely to have starvation problems on hilly terrain.
 
Bustamif said:
I'll confirm some numbers tomorrow, its an updraft carb, but not a 30 AKV. I'm told it could be same carb on some 1950's Peugeot's ?
Click to expand...
It could be a bitsa combination from different solex carbies, maybe get a photo of the R3042 in WA and compare ?
 
I was also thinking that that that (jet) is floor letting air in ,not fuel out ,so something amiss elseare is a possibility! I have had a couple of fuel fires on vehicles ,and it never ends up good ,remember it's not only the fuel that can catch but the vapour ,which can travel a long way on s breeze ,
 
A Solex Tuning Guide is attached FYI. Also attached is a drawing of automatic choke mechanism for a Solex 28IBT. The Solex 28IBT is a downdraft carby with an automatic choke. It is fitted to early Dauphines.
 

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harrisonati said:
A Solex Tuning Guide is attached FYI. Also attached is a drawing of automatic choke mechanism for a Solex 28IBT. The Solex 28IBT is a downdraft carby with an automatic choke. It is fitted to early Dauphines.
Click to expand...
I've just checked the Solex Tuning Guide attached and it seems to have been gutted. I'm currently searching for a complete copy.
 
i have an old carby book i can look up when i get home nxt week .
 
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The last few images are definitely my carb. Everything seems to be correct on mine however I found a non genuine spring under the brass disc in the cold start (choke) mechanism. The small non standard coil spring had been cut to shorten it which caused a high side on the modified coil. I have replaced it with one from stock and hope that the leak was related to the disc not sitting flat on the alloy housing.

I have also lightly ground and polished all surfaces on the mechanism to make sure it has no fine scratches or imperfections and all surfaces are completely flat to give a perfect seal.

The photo of the gasket above also shows a slight variation to the one in my carb which could be a potential leak across a chamber. I will have a careful check and make a copy of the gasket in the photo. The next test will reveal if I have solved the problem.

Also interesting to see the caption on the above diagram that says "8cv 1932 / triumph spit MK3 1967 / Traction 11b 1955".

Thanks Col
 
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