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Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 12:32 am
by tdskip
Hello gentlemen.

When I picked up the last batch of parts for my ‘69 the carbs that came with it are mismatched.

As you can see in the picture one carb is missing a vent tube (yellow arrow) and choke assembly (red arrow).

I checked the manual but I didn’t see anywhere that indicated only one carb would have a choke or vent tube. On my TRs these were always a matched identical pair.

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Thanks!

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 12:41 am
by tdskip
Sorry, should have added that these have been blocked off as well.

Edit: These are the bypass valve assemblies. Apparently it was someone come in to block these off back in the day.

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Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 12:49 am
by h20hamelan
Do you need or want the chokes, SoCal?

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 12:56 am
by tdskip
h20hamelan wrote:Do you need or want the chokes, SoCal?


Hi - hope it has been a good week for you so far.

I think I do want them, I use my cars up/down the West Coast and on the Copper State 1000 it was cold in the mornings.

Hopefully it will be warm here still when I get the car back together but I have a spare set of ZS carbs from a TR6 that I can borrow parts from as needed.

Thanks for the response.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 2:02 am
by SENC
Assuming that is the back carb, where the yellow arrow is pointing is where the fuel line would enter if it were the front carb (ie., these are mirrored since the fuel lines enter from between the carbs, rather than symmetrical) and so should be plugged on the outside.

I understand the bypass valves were only on federal cars, and were often removed and blanked as they added little value and more room for problems.

Though I suspect the chokes were generally on both carbs, the usual choke system only activated one of them (on the few cars I've seen, including mine), so leaving the unused one off would have added lightness! It looks to me like the prior owner felt the need to add a throttle return spring there - it would have normally between the carbs from the throttle spindle to the airbox.

Anyway, if you need the choke bits, I have several spares in my box.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 2:26 am
by tdskip
Thank you for the response.

I will leave the bypass assemblies blocked off, less stuff to rebuild!

I should have a donor choke assembly on hand, but if not I will let you know. Very kind of you to offer however, thank you.

I’ll get these torn down in soaking in carb cleaner, I think I have everything I need to get these rebuilt with good quality kits.

Thanks!

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 11:57 am
by snowyelan
My 69 non-federal only has one choke attached....although I would have to check if the other carb has one fitted.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 1:44 pm
by tdskip
snowyelan wrote:My 69 non-federal only has one choke attached....although I would have to check if the other carb has one fitted.


Good morning and thank you for the response. How does she do on a cold start with only one choke working?

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 1:51 pm
by 69S4
I have separate cables going to the chokes on each carb (dates from the time when the original cable wasn't available) and I often just use one. Takes a little longer before it'll run evenly but unless it's really down near freezing it's not a problem. The second cable (to the front carb) is set up to control the fast idle more than the rear one so I can juggle enrichment and idle independently.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 2:55 pm
by tdskip
69S4 wrote:I have separate cables going to the chokes on each carb (dates from the time when the original cable wasn't available) and I often just use one. Takes a little longer before it'll run evenly but unless it's really down near freezing it's not a problem. The second cable (to the front carb) is set up to control the fast idle more than the rear one so I can juggle enrichment and idle independently.


Thanks for the feedback, maybe I’ll just keep it simple for now.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 6:49 pm
by saildrive2001
My original European spec Stromberg engine had a choke cable that came down through the choke of the forward carb, then the inner cable with a separate piece of outer cable came back up & over the rear carb & down through the choke on it. After the original cable wore out I have tried several times with different cables to replace it but with limited success. I have made a custom design that still uses both chokes but only requires the cable to operate a single lever.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 9:30 pm
by SENC
That is slick, Saildrive.

TD, the single choke works fine. It only allows additional fuel in the one carb, but because of the linkage both carbs get the throttle opening.

Re: Carbs should be symmetrical, correct?

PostPosted: Fri May 29, 2020 9:40 pm
by tdskip
Thanks Henry and everyone who responded. Will leave this alone for now and rebuild these as set up.

Hope it's been a good week, Happy Friday.