Lotus Elan

choke cable

PostPost by: avhation » Tue Nov 27, 2018 10:35 pm

My Elan S3 weber choke cable is nearly broken, after relying on it for too long when starting with old fuel and gummed up carbs.


It seems prudent to replace the cable before it actually snaps. Having disconnected the cable from the carbs, is it simply a case of pulling out the handle to remove the old cable and then solder a new one in place (as described elsewhere in the excellent forum) and push it back through the conduit? Or should I attempt to pull through the conduit a length of wire with the old cable and then pull the wire from the carb end to pull through the new cable?
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PostPost by: Concrete-crusher » Tue Nov 27, 2018 10:45 pm

I tried to solder a new cable to the choke shaft , I’m dammed if I could get it to fix so would be very interested in knowing how others have done it

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PostPost by: lotusfan » Tue Nov 27, 2018 11:44 pm

Silver solder will fix the new cable to the shaft.

Grease the new cable before you push it down the tube on it's way back to the carbs.
Mike
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PostPost by: JonB » Wed Nov 28, 2018 8:43 am

Concrete-crusher wrote:I tried to solder a new cable to the choke shaft , I’m dammed if I could get it to fix so would be very interested in knowing how others have done it

Steve


I soldered mine using plumber's flux and solder and a blow torch. It's no good using an electric iron to do this, you need to go "full on" with a torch, but be careful not to over heat the cable. Don't let it get cherry red. I used a bicycle brake cable (I also keep a spare in the glove box in case the throttle cable snaps one day).
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PostPost by: rcraven » Wed Nov 28, 2018 11:05 am

Wouldn't there be a risk of soft (plumber's) solder eventually cracking through the stress of regular use (though some people don't believe in using the choke regularly)?
But if you do use soft solder a traditional large copper lump soldering iron heated first in a blow lamp might be easier to control and avoid overheating and hardening the wire. I've obtained them on ebay in the past.
Robert
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PostPost by: alan.barker » Wed Nov 28, 2018 11:41 am

Who needs a Choke with Webers or Dellortos :?
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PostPost by: JonB » Wed Nov 28, 2018 12:24 pm

Alan, my Dellorto equipped engine only starts reliably from cold with the choke out. I used to do the "no choke, pump the throttle" startup and wondered why the engine kept flooding.

Webers may be different (in which case, why bother fitting a choke in the first place? i'd have thought the ever tight fisted Lotus would have deleted it if not required).
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PostPost by: alan.barker » Wed Nov 28, 2018 1:50 pm

Hi Jon,
In 19 years with my 1972 Elan Sprint ( Dellortos) and 8 years 1973 Elan +2S130/4 (Dellortos) i've never used or needed the Choke.
Before that with 1968 Ford Cortina Twin Cam, 1968 Lotus Elan +2, 1970 Elan +2S all with Webers never used or needed Choke.
Maybe in 45 Years of driving Cars with Lotus Twin Cams i've just been lucky, who knows :?
I'm pleased using the Choke for you works.
Best regards
Alan
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PostPost by: Keith Scarfe » Wed Nov 28, 2018 4:52 pm

Who needs a Choke with Webers or Dellortos

I never understand this comment, and it crops up quite often. Yes you can run the engine from cold by stabbing at the throttle all the time when idling or heal and toeing to keep the engine running, but simply engaging the choke circuit raises the enrichment and rpm so everything runs smoothly. Well it does on mine any way, I wouldn't be without it. It makes driving when the engine is cold a breeze. The choke is just another circuit in the carburetor that requires tuning like all the others. If it doesn't work then it isn't tuned properly or is faulty. I would suggest if yours runs fine when cold that your idling circuit may be too rich.
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PostPost by: types26/36 » Wed Nov 28, 2018 5:09 pm

I agree, the a/f ratio should be approx 14:1 for cruising.
12:1 at idling.
9:1 for starting.
It can be started by pumping the accelerator pumps without choke but If it runs smooth from cold then it is too rich.
https://www.quora.com/What-is-the-ratio ... igh-speeds
I always use the chokes on both my weber S2 and my Delorto Sprint.
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PostPost by: Orsom Weels » Wed Nov 28, 2018 5:27 pm

My +2 will not start & keep running, & never has, without the use of the choke. It's on it's second set of Webers, 151's now, jetted to the same spec as the old ones. Without using the choke & just pumping the throttle, it may start, but will just stumble & die, even in the hottest of weather. I tend to agree with comments about being a touch too rich if they will start & run without the choke. The other thing I find is when set up correctly, it will sit there ticking over all day long without fouling the plugs or any other nonsense. When I first got my Elan, it would start & just about keep running without choke but would not idle for very long before fouling a plug or choking it's self up, so as an experiment, I swapped the smaller idle jets from my old +2 carbs & now it idles nicely but does need choke to start & run cleanly. (From cold)
With Dellorto's, if you have the accelerator pump jets that squirt downwards, rather than down the inlet tract, pumping the throttle to start instead of using the choke can lead to fuel collecting in the air intakes, then a little backfire can have undesirable & unwanted results!

Regards, Tim
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PostPost by: JonB » Wed Nov 28, 2018 5:59 pm

alan.barker wrote:Hi Jon,
In 19 years with my 1972 Elan Sprint ( Dellortos) and 8 years 1973 Elan +2S130/4 (Dellortos) i've never used or needed the Choke.
Before that with 1968 Ford Cortina Twin Cam, 1968 Lotus Elan +2, 1970 Elan +2S all with Webers never used or needed Choke.
Maybe in 45 Years of driving Cars with Lotus Twin Cams i've just been lucky, who knows :?
I'm pleased using the Choke for you works.
Best regards
Alan


Hi Alan

I'm not challenging your statement that you don't need the choke, merely saying that on my car at least, I do need to use it in order to get the engine running from cold without flooding it.

These cars have such different personalities - no two are alike, so it seems..

:D
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PostPost by: RichardHawkins » Wed Nov 28, 2018 8:52 pm

My wife has a smalll culinary gas powered blow torch. I find it ideal for silver solder on Bowden cables. The flame is hot but small, so there is less risk of damaging anything close by. I use Johnson Matthey easy flow solder and flux.

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PostPost by: alan.barker » Thu Nov 29, 2018 7:06 am

Maybe it depends if you have adjusted the Mixture on the rich side on Tick over or the lean side.
I tend to adjust Tick over on the rich side which of course will mean less need for Choke when cold.
When i start the Car from cold i then drive it and don't leave it ticking over.
I only leave ticking over when hot to adjust Carbs and Timing.
I have never had a Twin Cam with Stromberg Carbs but i think with them Choke would be needed.
Alan
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PostPost by: avhation » Thu Nov 29, 2018 4:01 pm

Thanks everyone for your contributions. Mike has answered my question. :)
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