Ford sierra - Webber tick over too fast

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Tue 7 Jun 2016 16:44
Ford sierra - Webber tick over too fast - Sabreblue
Where 28/32 TLDM auto choke carb with tick over at 1500 when hot. The throttle lever can be pushed back on to the throttle stop to reduce rpm to 900. When the engine is not running the lever rests on the throttle stop but as soon as the engine is running again the lever will not return to the stop unless pushed. The auto choke is working as the butterfly valve opens as the engine warms. The fast idle adjustment seems ok as when hot the fast idle adjustment screw is clear of the fast idle cam. Any help would be much appreciated.
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Tue 7 Jun 2016 17:24
Ford sierra - Webber tick over too fast - RT

When was it last cleaned and decarbonised?

Older engines, or badly maintained engines or those run on the wrong oil can quickly build up deposits of carbon from the oil contained in the blow-by gases - as well as restricting jets it can also close up the clearances in the plain bearings used by the various control adjusters.

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Tue 7 Jun 2016 18:45
Ford sierra - Webber tick over too fast - elekie&a/c doctor

Has this got an electric connection to the choke unt,or is it water heated.?

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Wed 8 Jun 2016 09:11
Ford sierra - Webber tick over too fast - Sabreblue
It's an electric auto choke with a water hose assist. This appears to be working well. I do not know when the carb was last cleaned but it looks ok.
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Wed 8 Jun 2016 09:23
Ford sierra - Webber tick over too fast - elekie&a/c doctor

If you are happy that the choke system is fully off when hot,then it may be an idea to unclip the throttle cable from the linkage to see if there is any mechanical binding up of the butterfly system.Just an added test,with engine running there should be around 7-8 volts at the auto choke wire.

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Thu 9 Jun 2016 12:12
Ford sierra - Webber tick over too fast - Sabreblue
Yes, I have checked this. When the engine is running the throttle lever is about 2 MM. off the throttle stop. When the engine is switched off I can see the throttle lever slowly return to the stop. I don't think the problem is mechanical. It seems as though a vacuum is holding it open. I have looked at the vacuum operated choke pull down but this seems ok.
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Mon 13 Jun 2016 16:18
Ford sierra - Webber tick over too fast - Sabreblue
Many thanks for your assistance but got it sorted this am. The adjustment was out on one of the two vacuum assisted throttle kickers.
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