Carburettor return springs.

[Harvey]

Looking for some help with where to mount return springs on Weber Carbs.

 

Using a Twin cable, top mounted linkage.

 

Regards.

 

 

[philwaters]

Is this the 'Weber' Twin Cable Top set-up? In which case I would be very carful as I have heard that it can clash on the bonnet louvres (spelling?) and ractchet itself into position leaving you with a wide open throttle and no way of closing it 😳

I have the under carb twin cable set-up and it is fine. The cable runs are pretty short and fitting it all is straightforward, if a little fiddly. That is with twin 40DCOE's.

 

Phil Waters

You mean you can drive these?

I thought it was just there to polish 😬

[chris perry 1]

phil,

 

i have problems with the throttle cable sticking on my 8v vauxhall. Where do you get the twin cable set up?

 

Chris

[Phil Bishop]

Besides the weather gear (!) I had more trouble with the throttle linkage than anything else when building my Seven. The Weber return spring supplied was useless and just wasn't man enough to close off the throttle. I went down to Dartford and bought a second spring kit, that is supposed to do the job but doesn't. The trouble is that the spring itself (like a big folded out safety pin) is trying to push too much weight at too close a point to its final resting position. In the end, I noticed a spare threaded hole on the side of the engine block, fitted in a little bolt with a big flat washer, with a small hole drilled in it, and stretched a spring I had in the tool box across the gap to the throttle arm. I suppose I was lucky that I had a spring just the right size - about three inches long, I suppose - and originally intended for holding on the exhaust on a kart. (Never throw anything away!) Caterham never objected when they checked over the car, and neither did SVA, so I can't have committed any cardinal sins.

[Chelspeed]

Twin cables will not prevent sticking, in fact it'll make it twice as likely. The benefit is the opposite, if one cable breaks you can still drive. This is useful on a 20 mile rally stage but is the added complexity and weight really necessary on the road or on a sprint? I'd keep it simple and accept that once in every 2000 sprints you might loose a run due to a broken cable.

 

If you've got a sticking throttle solve the reason why it's sticking. Take everything off the carb or throttle body, is the spindle free? Put the linkage back without the cable connected, is it still free? Put the cable back on the engine end but not on the pedal, is it still free? Then connect it to the pedal, try it again.

[philwaters]

Chris,

I got my linkage from Raceline, but any Weber dealer will be able to supply it. It isn't cheap though, at ~£55. I had to change mine when I went to a Zetec and the old one wouldn't fit. The twin cable set-up does give a far nicer cable route though - no nasty bends/loops for water to sit in.

As Chelspeed says, an extra spring on it's own won't fix a sticky throttle. Could take the carbs off and check that the butterflies are seating correctly and also you'll be able to compare carb for carb to locate the problem. Messy job though.

 

Phil Waters

You mean you can drive these?

I thought it was just there to polish 😬

[Harvey]

Phil,

 

Thanks for the info,I will try that.

 

Hope that will be suitable for the Auto-test scrutineer.

[Swiss_Tony]

Harvey

 

If its only for a scrutineer, weber carbs should have return springs built into the throttle spindles - one either side of the carb just behind the washer.

Obviously an additional linkage will help. I use the under slung linkage which works a treat.

 

James

Su77on Se7ens