Zenith Choke Questions

StephenZ

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Okay....So I'm rebuilding my Zeniths for my E3 and all is going well, except for the electric choke portion. I took apart the electric heater rectangle and it's in pieces inside. I'm having a heck of a time googling anything about the electric portion of the chokes
A. Is this part available anywhere? I've googled a bunch of variations of the name of the parts, but can't find anything.
B. Will the chokes work with just the coolant hooked up? Or will it take too long to heat up the spring with just water temp and no electricity?
C. What are my options if I can't get the electric parts replaced?
thanks everyone.

-Stephen Z
 

HB Chris

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I think chokes get a signal to turn off from front manifold temp sensor which perhaps is more accurate than waiting for the manual springs to release?
 

deQuincey

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I think chokes get a signal to turn off from front manifold temp sensor which perhaps is more accurate than waiting for the manual springs to release?
IMHO, that is correct in the versions equipped with ecg, that have a 17 deg sensor under the front manifold, but not in our euro versions in which i see no way to disconect the elctric chokes

my first question to @StephenZ is to post a pic of the part he is looking for, cause in my mind it makes no match choke with rectangular, there are rectangular boxes in some versions but no coolant is run across, ...?
 

Honolulu

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There is a sensor of some sort under the manifold but I've never looked closely to see what it connects to.

AFAIK the choke is actuated partly by circulation of coolant (two small hoses on the rear of the device) and by a hot line which energizes a coiled heater element. Heat from either opens the choke.

On some carbs there is another electrical element in a small rectangular box on the choke, a bimetal strip opens when heated by a wire to open a quite small orifice that allow a bit more air in. This device is supposedly only active if temps are unde 70-odd degrees F, you may never see it active in Hawaii, what is your local ambient temp?

Simpler is better to me and Weber 32/36 looks worlds simpler than a Zenith 35-40 INAT after you've been into both.
 

StephenZ

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deQuincey, sorry, I didn't do a good job of describing the part...:) It's the thermostatic valve that provides electrical assistance in heating the bimetallic spring in the choke housing that does have coolant flowing through it. I found it on W&N but it's 170bps...yikes. I managed to disassemble it next to my other one that is nicely intact and solder it back together again. Will it work? Time will tell...;-)
Honolulu, yes, you're correct. I guess my frustration was not being able to find really good info, not just on how it basically worked, but what people have done when it's too far gone to repair.. I understand going for simpler with the webers, too, but I'd love to make these babies sing again! I've redone many different carbs on lots of cars and feel like I'll be able to get it there if I can find answers to these things. So, THANK YOU to all of you guys on here!!! I love being able to have a resource like this. Here are a couple shots of the Thermo valves now.. and yes, I'll take care of the last bits of grease on there before they go back on...:)
IMG_4439.JPG
IMG_4440.JPG
 

deQuincey

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deQuincey, sorry, I didn't do a good job of describing the part...:) It's the thermostatic valve that provides electrical assistance in heating the bimetallic spring in the choke housing that does have coolant flowing through it. I found it on W&N but it's 170bps...yikes. I managed to disassemble it next to my other one that is nicely intact and solder it back together again. Will it work? Time will tell...;-)
View attachment 19258 View attachment 19259
there is no coolant across that one, this has only an electrical resistance and a bimetallic plate with a small tip that acts like a valve for the passing air

moreover if you drive in a climate that has no low temperatures you can bypass it
 

StephenZ

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Yes, that's what I had said....it only assists the choke that has coolant flowing through it by helping heat the metallic spring during warm up.. It does NOT have coolant going to it. We're saying the same thing...:). I know it never had coolant in it...I just wondered how important it was in the choke/initial warm up portion of the cold start... But I think I have it back together again, and it's actually a very simple mechanism...Also hoping that, being in SoCal, It probably won't get cold very often to rely on it much. Thanks again for all the replies, it's always very helpful to toss the info back and forth, as it usually helps me think of something I missed..great way to solve things. Thanks!!
-Stephen

edit*: yes, bypassing it was what I was wondering about..so if it ends up not working I'll probably just take it out of the loop. Thank you deQuincey!
 

deQuincey

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bypass in socal, absolutely !
there are meant for cold start below 15 deg cels
for bypassing simply remove the pointed tip, do nt remove the whole thing, you can leave a piece of electric wire for aesthetic purposes
 

StephenZ

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bypass in socal, absolutely !
there are meant for cold start below 15 deg cels
for bypassing simply remove the pointed tip, do nt remove the whole thing, you can leave a piece of electric wire for aesthetic purposes
Thanks!! One day later in the year when I get it put back together, I'll see how it all works...:)
 
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