Lancia Motor Club

I have rebuilt my Solex Carb fitted to my Flavia Vignale and would like to know how to test the functioning of the second (vacuum operated) choke.

I have replaced the perished diaphragm (although it did not look like it was totally u/s) and the car runs nicely in the garage but I cannot see the second choke opening in garage running conditions. I should say I checked the air(-ve) way to the diaphragm and installed new gaskets etc. All the other part of the carb seems to work properly including the accelerator pump.

Any help especially a manual on the carburettor would be great.

Thanks

Tim

If you can see 110 MPH on the speedo it's probably working OK!

Colin

Thanks Colin!!

Cant quite get that in my garage  >:(

Did you have any trouble with yours?

Tim

A different model with mention of a third butterfly, so may or may not be of interest.

Thanks Richard

It is similar but not with the third butterfly! I guess I need to drive it on the road. More anon.

Tim

My Flavia had Kugelfischer petrol injection so I never had this problem. My Beta 1600 had a twin-choke carb with the second one only opening up under load, which is not easy to check other than on the road. Maybe Betaboyz can advise.

Colin

On the Beta the second choke opens when you give full throttle (in sync with the accelerator pump - more fuel & more air). The Beta carbs are Weber though.

Took it out for a local run yesterday with Sarah driving (she loved it) and while we did not get anywhere near 110 it certainly ran well with lots of urge  ;D... so it may well be OK only time will tell.

Still on the look out for a manual on how the carb works though. A part list/pic doesnt really do it. >:(

The Sunbeam Alpine and Humber Vogues used the same carburettor. The workshop manual has a very good section on the carburettor.
You won't be able to determine if the second throat is working 'in the garage'. The opening of the second throat is dependent on two things. Air speed through the primary throat has to be high enough to provide a low pressure on the non-vented, upper section of the diaphragm. Secondly, the accelerator pedal has to be beyond about half-open. At that point the mechanism on the side of the carburettor will allow the second throat butterfly to travel in unison with the primary one. If you carefully adjust and lubricate the accellerator linkages and cable you should be able to feel through your foot when the additional effort needed to open the second throat comes into play.
It is worthwhile setting it all up properly. My Flavia 2000 returns up to 30MPG (in real units) on along trip.
Good luck.
Brian Long

Thanks Brian

will wait for some good weather and see what transpires.

Tim

saw genuine 95 and still going when I noticed I had gone into the red 5500 rpm so eased off. No sign of strangulation so I assume all is working!?

Tim

That sounds good. The Kugelfischer Flavias had longer legs and gave more than 20 mph per thousand rpm – see photo. I think the Zagato cars with twin carbs did too.

Colin