Lotus Elan

Weber throttle return?

PostPost by: Rob_LaMoreaux » Wed Nov 08, 2006 4:21 am

I finally got the Weber engine running in my Elan, and in the short 8 block
drive I took on Sunday, I like it much better than the stromberg engine with
the DBE 112 cam. Part of that was the better flow balance of the webers
giving a better idle, and much of it I am sure is the McCoy high lift cam
and porting job.

I do have one issue with it. The throttle does not always return completely
to idle. Is there a throttle return spring somewhere?

I haven't had a chance to look through the manuals since we left for the
hospital Sunday evening for my daughter to be born and I didn't get home
until a few hours after she was born last night. Since my wife and daughter
won't be home until tomorrow and my step son is in bed I get a couple of
minutes to ask.

I do want to get my car running a bit this week before I drive her over to
my in-laws for winter storage, so I will appreciate any suggestions.

Rob LaMoreaux
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PostPost by: Lincoln62 » Wed Nov 08, 2006 4:49 am

Rob

Congrats on the new daughter.

As far as I know they didn't come standard with any spring other than
the ones in the carb bodies. If yours is the same as mine i.e. inner is
fixed at the end and outer moves the linkage, when you close the hood it
pushes down and puts pressure on the outer making it harder for the
throttle to return. A low friction cable solves this but a secondary
spring wouldn't hurt either. I made up a bracket that goes between the
two carbs using two of the screws that hold the top cover on. Then a
spring from that down to the actuating lever. We are required to have a
secondary return spring when we run on the track in Australia.

Cheers
Peter
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PostPost by: davidallen » Wed Nov 08, 2006 12:10 pm

Congratulations on the new arrival! You need a +2 now

I have been down this path! There is a second spring which is located
between the two carb's, fixed, I think, between the carb actuating
leaver and the airbox. If you look at the actuating lever you will see a
small hole where one end of the spring attaches.

The spring is not a coil type but (best example I can think of!) similar
to used on clothes pegs. The throttle inner cable is fixed and the
linkage actuated by the cable sheath as Peter describes.

David

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PostPost by: dfysh » Wed Nov 08, 2006 1:01 pm

In 2000 I bought the required throttle return spring from Bean. It is item
number 026S 0028 and cost $9.50 at the time.

Don Fysh
S3/5607
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PostPost by: "Jon Eckman" » Wed Nov 08, 2006 2:27 pm

Hi Rob:

My congats on your new family member as well - take lots of pictures!

After replacing the return spring on my 66 S3 webered TC and still having an intermittent problem dropping back down to idle, I lubricated the throttle cable (on advise from the group) and the problem went away.

As David mentioned, the airbox cover for the webers has a slot for both the return spring and the throttle cable to mount to.

Good luck,
Jon

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PostPost by: ddddumas » Fri Nov 10, 2006 7:04 pm


Rob,
First, congratulations; children make it all worthwhile. Second,
all previous replies have been correct, but if I may elaborate a
little more. I had this same problem when I bought my S2. For a
better visual, I would describe the original "clothes peg" spring as
the spring end of a giant safety pin. The wire is about 1/8" dia.
and the spring's elbow-eye about 1" dia. It's not something you're
going to easily come across; it appears to be purpose-built. The
original spring assembly was on my S2 when I bought it, however the
DPO had added two additional helper springs hooked to a cross bar
added between the tops of the Webers. I tried to make it work both
with and without the helpers, but finally gave up. I have been
using the "26R throttle cable assembly" for several years, and
although not original, or even as Lotus minimally clever, my
throttle return issues are gone, gone, gone.


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PostPost by: Nigel Furness » Mon Nov 13, 2006 11:57 am

Hi All

You can use the "clothes peg" style return spring from
an early Esprit, Excel or Elite. I have used this
with both 40 and 45DCOE carbs. The springs are
obtainable from both CN and Paul Matty in the UK. You
usually thin down the end of the spring. It fits the
bracket on the airbox backplate with no mods (in my
case), though I did once have a problem with the spot
weld failing where the bracket is welded to the
backplate. Rather than try welding near the fuel
lines, I replaced it with a bolt - 12 years ago. No
problems with this arrangement at all and a steady
idle speed is achieved, except when I occasionally
trap the throttle cable with the bonnet...

Regards

Nigel
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