My 1972 E type lately has developed fast idling at about 2000 - 2500 RPM. In order to return to 750 RPM, I need to give the accelerator pedal a kick while in neutral gear.

I've checked all the throttle and choke linkages and cannot see anything wrong.

Could this be due to a faulty Stromberg carburetor by-pass valve(s) or any other problems that you may have experienced and if so how do I know which of the 4 carburetors has this problem.

Tony Teo
E type enthusiast

Submitted by tony.teo@dnv.com on Thu, 01/02/2003 - 17:15

Thanks for your tips.

1) I found that the throttle linkage was partially held by an obstruction under the LHS carb. This has resolved the 2500 RPM idle, however at normal temp. the idle speed is still high at 1200-1300 RPM.Anyone with solutions will be very much appreciated.

2) Also this obstruction come from a small diam. metalic tube connected from the C vacuum hose and stops "exposed" under the carb. located nearest to driver side. Can anyone tell me how or where to, this tube is connected under this carb.

Tony Teo
1972 S3 XKE OTS

Submitted by cleavefamily@c… on Fri, 12/27/2002 - 15:42

After achieving the fast idle turn the engine off and check the position and fit of the throttle discs by removing the air filters and raising the pistion by hand with a long screw driver so that you can look into the horizonatal throttle bore. The discs should be closed and snug. If not closed and snug the adjustment has sliped. Also wiggle the throttle shafts, there should be no play. If loose, you may have a vacuum leak through the shafts which would cause a very eratic idle, but not necessarily a fast idle. With the air filters off, listen to each carb with the engine running by running a hose (I assume you don't have a synchronizing tool) from your ear to the carb face, the suction noise should be even. This will tell you if the problem is in all or just one of the carbs. I'm not a Series 3 guy and this is all I can help you with, perhaps George Camp will pick up on this and help you out. George is batting well over 500 at present. Oh, BTW don't stick the hose in your ear, just hold it close so you can hear the suction.

Stew Cleave
JOCO Chief Judge
'69 E-Type 2+2
and other LBC's

Submitted by tony.teo@dnv.com on Fri, 12/27/2002 - 14:17

Thanks very much for your reply, Pascal.

I checked the big and small springs and on release, all the throttles & linkages come back to their original positions but the engine still remains at about 2500 RPM.

Any idea that you or anyone else may have will greatly be appreciated.

Tony Teo
E type S3 Roadster

Submitted by pascal@jcna.com on Thu, 12/26/2002 - 17:46

It sounds like you have a faulty return spring. I don't think an internal carb problem would cause such high RPM.

on the V12, you have a large spring would up on the throttle pedestal in the vee. If that fails ( happened to me once) the smaller spring on the carbs will work to some extent but much weaker. when I lost the big spring, suddenly my car felt like it had another 100 hp... the feeling was completely different.

when it happens, pop up the bonnet and try to see what hangs. tap the round piece on the throtle pedestal to see if it snaps back.

Mine sometimes used to stay at at a faster idle after a hot run, but only by 3 or 400 RPM

Pascal Gademer
72 E-type 2+2
00 XKRCoupe
99 XJR