The other day I was disengaging the automatic choke on my 77 bus. It has twin carbs (stock solex). The right carbie has a 'bypass mixture cut off valve' but the left does not. It doesnt seem to have a screw either. The valve is an electromagnetic valve and has a wire from the coil connecting to it. Does anyone else fly solo.

NB If the valve is not connected to the coil the engine runs like a dog and blows flames out of the exhaust along with backfiring when slowing the car through the gears.

If it is the valve i am thinking of it is the one on the lh carb towards the front of the carb. It connects to the air system. I had trouble with mine being loose and was sucking air around it causing the motor to idle low and run on

It is involved with the central idling system and needs to function

Mine only has one cut-off valve (I can't remember which side) and it is enough to prevent running on.

Those anti-run on valves block fuel in the slow run (idle) circuit of the carb so if they're not powered off ignition then yeah, you get those flames and fun and games on throttle overrun!

Some cars use an external air bleed valve that opens when the ignition is switched off and let fresh air into the manifold under the carbies so the carbies wont draw fuel when switching off to prevent run on.
Curious there is only one tho?? Must be enough.

L8tr
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when i re-attach the wire from the coil to the cut off valve, things are good again. It is odd that there is only 1 especially as there is a wire going in that direction with nowhere to connect to! Mmmmm

the pasenger side carbie has a central idling system cuttoff solenoid near the top in the cover, & both carbies should have another cutoff solenoid high in the body to the outside of edge of engine, it was common when these die for the to be replaced by a normal idle jet which screws straight in, you should be able to feel it, it is located exactly where the other one is, it wont do any harm to have it.

Everything came good in the end

The electronic cut off valve is required but you only need 1 and...

I reakon my bus runs better with the auto choke disengaged.

Thanks

what do you mean disengaged? did you just pull the wires off or did you take the choke off and wire the flap open?

Okay i will assume this is the same on all solex carbs as i have done this on both my 34 and 28 pict beetles. John muir describes auto chokes as a conspiracy by car makers to get your engine to run richer decrease engine life and ensure you by more parts/engines from them. he describes how to disengage in his books something like this.
To the right hand side of the carby you will see a round device about the size of a twenty cent piece that is clamped by three screws. this has a wire running from it to your coil and will be stamped solex 12v.
1) remove wire and tape off and secure in place out of way. you can cut and permanently remove but then it is harder to reconnect in future if you need to.
2)loosen the three screews on the choke mechanism enough so that you can rotate the circle , do not take all the way off just loosen so that it easily moves , rotate it in one direction and it will open the butterfly valve in the carb, turn it the other way and it will close the butterfly valve in the carb. To disarm you want to turn it so that it opens all the way and then keep turning in that direction as far as you can and then tighten the three screws and the auto choke is disarmed. this means that at start there is no choke at all on and you may get a harder start just pump your foot a couple of times before ignition to get fuel in and then let your motor warm up properly. on the left side of the carby is the fast idle cam this is the toothed swinging lever that allows a fast idle you need to tie this back so that it does not affect your idle i just tied miine back with a rubber band

should i disengage my auto choke. what do people think?

I did it exactly the way described above.
I am trusing the logic of this manouvre.