Weber DCOE 40 151 spindle binding

[NTG999]

Hi, my Elan Sprint is just back on the road after a number of years. I have found revs would not return to idle especially when warm, on the bench removing the nuts on the end of the spindles (which were tight) appears to solve the issue, my question is how difficult/problematic is changing the bearings. They appear to be open with a small metal washer then the large outside washer?
My second question; the chokes have been machined out from 30mm to 33mm, would buying 33mm chokes give any real life improvement?
Nick

[Lotus54]

Ones I’ve seen have a leather ‘seal’ then a metal cover. I just replaced with sealed bearings.
Could be the bearings are tired- but the leather seal seemed to have a lot of resistance.

[mbell]

In my experience they will bind if tight and need to only to be nipped up. (With washer keeping them in place).

I've also found that new throttle levers have slightly to much material where the idle screw touches them. Stopping cars returning to idle. So worth just filing a little off it. While y you're there.

[stugilmour]

Nick, just clarifying. Are your 151 Webers a modern new pair? Not sure they would have the leather components the original Webers had?

As a separate suggestion, my modern Weber 45’s were having a similar issue returning to idle. Really annoying as I am still trying to tune them accurately.

I installed this auxiliary return spring kit and it is a huge help. I haven’t had a chance to road test this improvement yet, but testing out the setup in the garage it looks like a good thing. I also figured having a backup return spring is kinda smart; have seen some exciting video moments with throttles jamming open on track.

Somewhere when I was looking this product over, maybe on an Alfa forum, I saw a comment saying a secondary return spring can be a tech requirement for some track applications. Made sense to me so giving it a try.

This kit was also recently discussed on a different thread and other folks had good results with it. I can’t find that tread right now, and it was a kinda separate comment in the thread. Perhaps someone else will be along shortly with more complete results.

https://www.piercemanifolds.com/product_p/lt5000.htm

Same thing from a UK supplier

https://www.webcon.co.uk/products/10501 ... pring-kit/

HTH

[NTG999]

I think I have resolved the issue, my 151s were from about 1990 and didn't have leather seals. I have recently had them 'professionally' rebuilt!
I found the 2 new washers on the end of the spindles were slightly domed and binding, flatting on wet and dry helped plus the spindle nuts IMO were overly tight. This gave clearance.
I added the secondary Weber spring kit. My brother cut and hard soldering the arm to the existing part as I found it too thick to go on the end of the shaft as is. It now returns both carbs back very well