Throttle Return Spring fitting

[simonknee]

A new angle on an age old question...

To start with: I know how the spring fits, I have got an original airbox, I have webers, I have a new throttle linkage of the correct type from weber, I don't want to fit twin springs or one over the cable, I am not worried about the spring breaking (engine racing away - cut the ignition), I don't want to make my own brackets, I am happy with the original arrangement. Phew.

So why the post?

I am putting in a new throttle cable since the old one was a bit worn and did not respond to the yearly oil.
I thought I'd order a new return spring from PM at the same time since mine has always been a bit tatty and needed a cable tie to help it stay in place.

The diameter of the PM return spring is too large to fit the hole on the weber linkage!

I have found a post about this from long ago:
post63937.html

And from it: "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."

Looking at the old spring I realise that this is what has been done - it has been thinned (looks like with a swiss army knife).

So has anybody been here before and did you thin the spring or enlarge the hole?
If so how and what went wrong?

Simon

[cliveyboy]

Hello Simon
I have just replaced the spring on my Sprint but its Dellortos so fits OK.
The old spring and the replacement I got (not from Mattys) have diameters of 1.86mm(old) and 1.84mm(new)
What is the diameter of yours and can you size up the hole on the webers to see what size it should be?
If yours is a larger diameter I have a spare (1.84mm) you can have
Clive

[nebogipfel]

Simon,

It's a while ago but I'm pretty sure I remember relieving the holes slightly when I fitted my new spring. The difference was very slight but it wouldn't go through.

FWIW if you aren't talking about much I'd always relieve the holes rather than mess with the spring.

[Galwaylotus]

FWIW if you aren't talking about much I'd always relieve the holes rather than mess with the spring.

That should be a "no-brainer"!

[simonknee]

Thing is with drilling out the hole there's not much metal between it and the big hole the spigot goes in.

I found it weird that a dpo did the spring and a post talked about whittling down the spring.

Simon

PS I waffle.

[nebogipfel]

FWIW if you aren't talking about much I'd always relieve the holes rather than mess with the spring.

That should be a "no-brainer"!

Well yes but I felt I should answer the question in the OP

[simonknee]

I do concur on the "no-brainer" so I wonder why this "thin the spring" appeared in the 2006 post by Nigel and a dpo of my car did it some time before 2003.

The difference is about .5mm maybe a little more. Which doesn't seem like much but the existing spring hole is very close to the edge of the larger spigot hole so I think I would have a problem drilling it out and I don't have a needle file small enough.

In the image the small hole is under 2mm in diameter. Any no-brainer ideas on enlarging

Simon

[nebogipfel]

I do concur on the "no-brainer" so I wonder why this "thin the spring" appeared in the 2006 post by Nigel and a dpo of my car did it some time before 2003.

The difference is about .5mm maybe a little more. Which doesn't seem like much but the existing spring hole is very close to the edge of the larger spigot hole so I think I would have a problem drilling it out and I don't have a needle file small enough.

In the image the small hole is under 2mm in diameter. Any no-brainer ideas on enlarging

Simon

I'm pretty sure mine needed little more than a "clean" and I popped a drill through, but it was 8 years ago ...

You've got me wondering how close mine is now

[types26/36]

Maybe you could fit the Dellorto spring as it is thinner then the Weber spring.
(pictures taken from the S & J website)

[simonknee]

Yep, my springs, old and new, are the weber type. Looks like the dellorto type would reduce the need to furtle the hole and perhaps that is what cliveboy and nebogipfel actually have. I'll try and figure a way to enlarge the hole first but only into the meat of the lever.

Simon

[AHM]

Modify the bit that is wrong

[robertverhey]

My PO appears to have fitted a backup spring....might give some peace of mind.....

[simonknee]

Robert,

The other reason for an extra spring is that your dpo had trouble getting the linkage back to idle when off throttle. I'd remove it and make sure that everything still works OK. It could be that the original spring is no longer what it was. It could be a sticking throttle cable. Possibly the carb linkage is somewhat worn doesn't settle back nicely.

I'd only worry about the throttle cable but that is a part that definitely needs replacing when worn. Perhaps since it rubs on the underside of the bonnet it seems to wear pretty fast in my experience.

Alternatively the dpo might have had the main spring pop out at sometime so was a little paranoid!

[Galwaylotus]

Another thing to note regarding not returning to idle is this. I had some work done on my car a few years ago and when I got it back it was reluctant to return to idle. I found the cable had been ty-wrapped down, presumably to keep it from rubbing on the underside of the bonnet. I cut off the ty-wraps and the problem disappeared. Even lubricated, the cable can bind if its curvature is restricted.

[simonknee]

Have you got the correct gap in your thackery washers there Robert? Look a bit tight to me but maybe that is due to the blurry photo.

Simon