Lancia Beta Forum
Technical stuff => Fuel System Carb => Topic started by: JohnFol on November 25, 2025, 10:29:21 AM
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Morning all, can runs really well but I know the choke is a bit problematic.
Toying with the idea of replacing the automatic choke driven by water temperature with the electric equivalent.
Has anyone done that, or has a cautionary tale why it's a bad idea?
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my electric choke seems to work okay
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John,
These coolant chokes are normally reliable if set up correctly and
achieving good flow-through.
Due to the small apertures involved, especially at the extreme ends, i.e. the manifold
and lower water rail, flow can become restricted by crud build-up. The bowl can
also get blocked easily.
There are alignment marks on the bowl, I find they are generally accurate and useful.
Mark, I'm sure yours is standard coolant-driven.
Nigel
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nope, its electric heated
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nope, its electric heated
That I would like to see..
Peter
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Interesting.
What's the model type stamped on the flange?
Nigel
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I know it off by heart now
34 DAT 2/251 which matches my late version Lancia Service Manual (Jan 1982), jets are all over the place. Sorry just realised this is someone elses post...
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Mark,
For John's and our benefit, please post a pic of the electric choke, thanks.
Nigel
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I know it off by heart now
34 DAT 2/251 which matches my late version Lancia Service Manual (Jan 1982), jets are all over the place. Sorry just realised this is someone elses post...
Not a problem.
Ditto the comment about what the electric one looks like
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when I am in the garage I will take a photo. Its basically this
https://classiccarbs.co.uk/product/57804-333r-weber-carburettor-12v-electric-auto-choke-mechanism/
its powered off the solenoid feed, not that my car is the best to follow :D
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Hi Mark
Solenoid on the carb? Not sure that makes any sense, must be powered by something temp related or manually ( that would defeat having it as an auto choke).
Peter
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I assumed it heats up and winds the lever to open the choke. It does work
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Hi Mark
Yes, but what causes it to heat up is really my question. Ie the heating up process must be triggered by some event related to temp of the engine? On the wet system this is caused by the flow of hot water, so something must trigger the power to be applied to the heating element? Or am I misunderstanding how it works?
Peter
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I can test this theory when the bonnet it up next time.
I think there is a perm 12v supply when ignition is on to the anti overrun solenoid and choke mechanism. This makes sense as the solenoid uses power to keep it from cutting fuel until you kill the ignition. The coil inside the choke mechanism heats up and rolls back the choke flap over an x period of time. I will do a video over time when it’s back up and running.
Found this:
An electric choke heats the bimetal with an electric heating element to pull the choke off after a certain period of time. A non-electric does the same thing, but uses either hot water or hot air from the manifold as the pull-off assist.
On an electric choke there is usually a small set of contacts that break once the bimetal opens past a certain point to kill the current requirement.
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Hi
Ok so I guess it assumes that start of heating is start of engine and the time it takes for the bimetallic strip uncurl is approx the time it takes for engine to warm up. Crude, but I guess effective.
It would be interesting to know what markets they were sold in and when
Peter
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Yes, certainly an alternative to decaying coolant cover ports :)
On an electric choke there is usually a small set of contacts that break once the bimetal opens past a certain point to kill the current requirement.
I'd be surprised if there was a switch as wouldn't the bi-metal then cool down allowing the choke to close once again?
I'd guess the downside is that the choke might re-activate after a fuel stop for instance, while a water controlled version should still be be hot enough to keep the choke off.
That said, on the last X1/9s which had a 34 DATR 28/250, the water operated choke has a "resistor heater" similar to:
https://www.webcon.co.uk/products/3637-resistor/
This is inserted against the bi-metal unit instead of the plastic spacer and is controlled by an extra thermo switch in the thermostat housing to heat up the choke unit to keep the choke off if the main engine is hot, as the coolant at the choke could have cooled after a stop. Not saying it's a better idea, and personally not found the simple coolant choke itself an issue - the main problems have always been leaks at the hoses which can corrode the bi-metal unit or the choke flap spindle sticking necessitating a good clean.
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Could always add a simple circuit to the 12v that takes a feed from temp sensor in cylinder head....
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It seems to work a-okay in its current state. I had definitely had similar on cars BitD
Looking at Peter's wiring diagram its corresponds with a red feed from the ignition switch
https://lanciabeta.co.uk/forum/Downloads/Beta-Coupe-RHD-S4-wiring-Password-neromoto.pdf
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Did you get a chance to photo it on the car?
when I am in the garage I will take a photo. Its basically this
https://classiccarbs.co.uk/product/57804-333r-weber-carburettor-12v-electric-auto-choke-mechanism/
its powered off the solenoid feed, not that my car is the best to follow :D
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sorry its still in bits in my shed waiting for the float hanger to come back from being repaired. I did take this.
I also have a video I could share that shows it, or give me a week at it should be getting back together hopefully
PS - what exactly do you need?
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How about this?
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Thanks for that. I think I've gone down the wrong rabbit hole.
My car runs and pulls well, however the MOT garage adjusted the carb to keep emissions in the acceptable range. For me, it's now idling a bit too low and it has on odd occasions stalled. If you look at the picture the screw boxed in green has always been missing so nothing engages with the stepped cam. I had this idea that an electric choke would do away with that issue, but I don't think it does.
Reluctant to touch the mixture screw and introduce more variables so I was going to keep the idle a bit higher using the red screw.
As you can tell I have basic to mediocre understanding, but I'm not after fuel efficiency, max performance, just a reliable car that I can trust not to stall at lights.
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John,
You can safely turn the mixture screw anticlockwise to richen the mixture.
I'd suggest a half turn first, then road test. Repeat until it feels better but not more than
2 full turns. It should get progressively better.
That missing choke screw should be available from one of the weber dealers.
Your cold starts would improve.
Nigel
ps, I hope the mot guy was using the 4.5 max benchmark
and not the later lower figures.
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that missing screw would really make a big difference when cold. I think I have seen details on how it should be set up, I think its on the third step. I bet your choke will then be fine