Lancia Motor Club

Having read the Solex 40+ page pdf, I can't see any info regarding setting the float. I have a Solex C40PAAI. One thing I have read elsewhere is to install a sight glass or a level indicator to check the fuel without removing the top. Advice re fuel level welcome. Richard

Fulvia solex carbs are 19mm+-1mm measured from the top of the float chamber bowl casting edge. The most accurate way to do this is to access the emulsion tube and remove it and measure with a thin glass tube inserted (or a tie wrap) and measure the fuel level from that datum. Not sure if the same mechanism can be used for the 40

Thanks Tim, two emulsion tubes accessible with air filter housing unclipped. Richard

dont take top of float chamber off as you will get a false reading

Thanks, another job is to remove and clean emulsion tubes incase the air holes are blocked. Is there a preferred method anyone? Richard

A week in paint thinners did wonders with mine.

Thanks, I was wondering about accessing the e tubes? Richard

Hi, does anyone know the float level for the Solex 40 PAAI twin carb please.
Also any tips for best way to check would be appreciated.
Thanks
Chris

As Tim says. A 'dipstick' in the emulsion tube casting. Emulsion tube can be removed very gently with a stud extractor or similar, having first removed the air correction jet. My fuel level is approx half way up the float bowl. The Solex pdf is worth reading also. Richard

Hi all, thanks for your feedback. What's this Solex 40+ pdf and where can I get it?
Thanks
Chris

A 'solex pdf' Google search should have at the top of the list ' Solex, selection and tuning the carburetor, Arnolt Corporation, Indiana'. 48 pages to view or print. Also the float bowl may have a 'tidemark' to indicate existing fuel level. Richard

Ah, that PDF. Yes got one thanks but haven't read it thoroughly as I couldn't find reference to C40 PAAI. Will look again.

I've got a lot more soot in one tail pipe that the other. My first task will be to check the air correction jet and air slow-run jet on that side of the carb - any other suggestions on what might be causing it ?
Thanks

Best Chris

Looking forward to hearing the answer. Sooting in my case a while ago was cold start device stuck on, all cylinders affected though.Richard

Hi, I've been reliably informed that the float level for the Solex C40 PAAI is 16-18mm. This info came from a Lancia data sheet for this carb.
Chris

Excellent Chris, any chance of posting info from this data sheet. I for one have spent time trying to get things working properly. I have checked jet/ emulsion tube/ choke sizes etc. against info in my LMC workshop manual reprint. With my existing Solex, there is no positive 'stop' for the cold start device, although I think I have it correct with no whistling/frosting at the orifice. Richard

Hi, See Data sheet attached.
Chris

Many thanks Chris, I haven't seen this particular sheet before in my service literature. I will translate to english text for quick reference.
Richard

Is this any use Richard?

Close up

Many thanks Charles. I will have a look on a full size screen and print. Richard

Can I double check, this 18mm) distance is the measurement between fuel level and the machined top of float chamber body- not including the top casting (lid) where the needle jet is located?
Thanks Chris

That’s it.....”distance N is always intended from upper edge of the float chamber, gasket excluded, with tolerance of +/-1mm”.

I see it now, at the bottom of the 'close up'. What does the 'N' actually stand for, anybody? Richard

Someone mentioned that the lid needs to be on the float chamber to measure the fuel level. Why is this?

Also, I've noticed that I've got a small outlet (hole) in one of my the chokes. It's covered by the choke valve when it's closed.
It's about 1mm diameter. I get a lot more carbon deposits in the side's exhaust tail pipe. See hole in picture attached.

"Distance N mm" is the heading of the column that gives the measurement for each type of carburettor.

I’m not that familiar with the Solex single, as my car has the Solex triple P3 1/2. On the latter, the carb lid has to be in place because the float “needle valves” are mounted on it. It is the position of the float that acts on the needle valves that causes them to shut, hence resulting in a particular fuel level. i.e. if the float closes the valves earlier, the fuel level will be lower, and vice versa.

If the inlet manifold is anything like a 3B manifold, it consists of a plenum chamber. So fuel/air from either of the 2 chokes (or 3 in my case) can feed any cylinder. So more soot in one exhaust pipe than the other is unlikely to be caused by the carb.......I think???

I think the PAAI has one common float chamber, but one idle and main cicuit per cylinder bank. And one common cold start device. Richard

Charles,
Thanks for this.
Chris

Just in case its of interest to a single carb Flaminia owner, my inlet manifold is separated down the middle, as far as I could see and feel.
Chris

That makes sense....as Richard described....one choke per bank for a double choke Solex. Hence on the 3B, a triple choke Solex , I assume it is one choke per cylinder pair, from front to rear.

As you have one “starter” choke hole, then it also makes sense then that one bank exhaust gets sooty relative to the other. Is it normally that noticeable? Maybe other owners could comment, or is your starter choke runnng continuously?

Does anyone here know why only one bank of cylinders would need a 'starter hole'. Certainly when my PAAI 'starter' was partially stuck 'on' there was very bad sooting on all six plugs. I suppose if the hole in the photo could be closed off to prove a point. I have reliably heard that not all of the carbs in the triple Weber DCNL setup have a cold start device, but have yet to have a look at these and understand the reason why. I assumed all cylinders need a suitable cold start mixture. Will probably post a new thread regarding fuel injection, but does anyone know what injection system is available, as mentioned in the spec for uprated Aurelias with Flaminia engines which I have seen published? Richard

I would like to change my Solex 40 fuel level value 'N' from 24 mm to the recommended 18mm. There seems to be no 'tang' on the float arm to bend, so will install a thicker gasket at the mating face under the 'lid'. Initial thought was a 6mm gasket, before realising less than 1mm gives a 6mm difference in fuel level, due to the relative positions of float and inlet valve.

Yes, the 3C setup uses two slightly different types of Webers, the rearmost one having a starter (choke) while the other two has none.
I have assumed that Lancia intended the choke to be used only at the actual starting of the engine and not when driving the car, which is more common to do for a brief moment here in northern Europe.

Fuel level now 18mm from casting face. I have used 1.6mm paper gasket material. Looking at the float, there does not seem to be much more room between the float and the gasket to allow the float to rise any further anyhow. Also those air bleed jets which I mentioned in an earlier post can be seen in the photo (top right and bottom right), and hidden when the 'lid' is fitted . The cold start has a new bracket and the idle adjustment has a flexi shaft which connects to a dash mounted knob.
2nd photo is hand throttle revision.
Richard