Flexible carb coupling

I remember once reading (can’t remember where, now) that the spiral-wound flexible coupling between the rear carb and the accelerator linkage was made in both LHD and RHD versions. That is, the winding was RH wound on one and LH on the other. Because of the linkage geometry, the coupling on my car would have a tendency to slightly “unwind” thus introducing a slight degree of lost motion at the pedal. If it was wound the other way, it would be slightly more positive. However, I’ve only seen the one type, and indeed the spare parts manual only lists on part number C3597. Has anyone ever seen one specifically for RHD cars?

No, because the throttle shafts on XK engines always turn the same way regardless of LHD or RHD.
The coils look like a right hand thread, and the force applied from the pedal linkage would have the tendency to try to wind the coils tighter, rather than unwinding.
There is one for engines with the carbs on the left side, such as Jaguar pushrod engines, which would turn the opposite way, and can be recognized by coils appearing like a left hand thread. My Mark V and SS have them.

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Well, if you look at the picture of my car’s throttle shaft, it seems to me that with the rod pulled towards you, which is the way it goes, the spiral would tend to unwind… Am I missing something here?

You have a left-hand-thread type, for a pushrod Jag.
Here is the right-hand-thread type.

Ah, ha!! so it exists! Strangely, I ordered a new XK120 one from Burlen Services, and it was exactly the same as the one I already had. I’ll order another and make sure it is a RH thread! Thanks, Rob.

I spoke to Burlen Services, and they list only the one flexible spindle, and it is, strictly speaking, the wrong one for an XK Jag, being in fact, the correct one for a pushrod Jag engine. It seems strange, to say the least, that they can’t supply the very one that would surely be requested much more often…! However, I’m on the track of a second hand one, so am hopeful on that score.

OK hadn’t ever thought that this coil spring was RH or LH just a coil spring before anyone was selling them I was buying a tool that was used for tightening up hose clamps on radiator hose that has this exact same coil spring in middle to give you flexibility to reach spots and right diameter and they worked perfectly no idea if they were RH or LH ?

I remember those screwdriver type tools with a flexible section, too. I wonder if they had an inner layer with the winding the opposite way…? I’m sure in reality it makes little difference on the Jag, just seems slightly more desirable from an engineering point of view to have the winding tend to tighten as accelerator is applied. Anyway, I’ve managed to find an original one, so problem solved, in my case. :grinning: