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sheriffe karim
Yet to post message
Username: sheriffe

Post Number: 1
Registered: 10-2019
Posted on Tuesday, 15 October, 2019 - 01:34:   Edit PostDelete PostView Post/Check IP

the choke on my car is not working, when you turn the ignition on you get power on one side of the solenoid, but there is no ground on the other side;there is a relay there is a relay that turn on the solenoid but I don't know where it get its power from; if I apply power to the white/red wire the choke will work, can someone help me
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richard george yeaman
Prolific User
Username: richyrich

Post Number: 1124
Registered: 04-2012
Posted on Tuesday, 15 October, 2019 - 06:55:   Edit PostDelete PostView Post/Check IP

Hello Sheriffe welcome to this forum, I have not had any problems with my 1974 SS1 choke but I am sure you will get help with yours.

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David Hughes
Experienced User
Username: wedcar

Post Number: 97
Registered: 07-2004
Posted on Tuesday, 15 October, 2019 - 08:51:   Edit PostDelete PostView Post/Check IP

I am not familiar with the wiring on Shadow Cars, however here is the link to the workshop manual, the wiring diagram is contained in the manual.
Silver Shadow technical manuals are available on this website.
Trust this helps.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 552
Registered: 11-2017
Posted on Tuesday, 15 October, 2019 - 10:31:   Edit PostDelete PostView Post/Check IP

Try the Bentley Heritage website, cleaner diagrams, parts lists and service bulletins
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2160
Registered: 05-2012
Posted on Tuesday, 15 October, 2019 - 10:44:   Edit PostDelete PostView Post/Check IP

Hi Sheriffe

The choke solenoid earths through a thermal delay switch, also known as an otter switch. Since you are getting power to one side of the choke solenoid it sounds like the otter switch has failed. The bad news is this switch is located in the relay box on the left hand side of the bulkhead, just behind the voltage regulator. It is difficult to access.

Obviously, the choke solenoid cannot be wired to earth as it would be on all the time. Some owners rewire the choke solenoid through the starter relay, so it is activated just when the engine is cranking.

When you say the choke is not working on your car do you mean the choke butterfly is not opening/closing properly. Are the bi-metal thermocoil and stove pipes working.

The pic below shows the inside of the relay box. The choke thermal delay switch is labelled number 7.

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John Kilkenny
Frequent User
Username: john_kilkenny

Post Number: 317
Registered: 06-2005
Posted on Tuesday, 15 October, 2019 - 21:08:   Edit PostDelete PostView Post/Check IP

Here is the circuit of the Shadow 1 Choke Operation. Your 1973 Model probably does not have an otter switch, which is a temperature sensitive switch used to disable the circuit if the engine is warm.
The fault is probably with the thermal delay.

Choke Circuit
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gordon le feuvre
Frequent User
Username: triumph

Post Number: 319
Registered: 07-2012
Posted on Monday, 21 October, 2019 - 11:57:   Edit PostDelete PostView Post/Check IP

The choke operation is as follows: The main operation of flap intake is by a bi-metal coil. When engine cold if throttle depressed once this should activate bi- metal coil to close flap for cold start. This operation will also increase idle speed. As engine warms, choke should gradually return to open position influenced by hot air being drawn over coil and heating it. As choke opens engine will run faster. This can be controlled by “blipping” throttle to cut back jidle speed. If ambient temperature around zero, the choke magnet will be activated to hold choke butterfly in on position as the action of big pistons and slow crank makes engine “gulp” air which has effect of flicking choke butterfly partially open, which has effect of weakening mixture which is reverse of what is required on cold engine. By the magnet holding choke flap tighter under it’t influence engine will start. Once running, the scintilla switch will receive a signal from dynamo/alternator to break circuit and release magnet. The scintilla switch is adjustable and with a little trial and error good cold starts can be achieved. Out of interest on any Cloud/ Shadow/Spirit with carbs, reluctant cold start can be assisted by choke being held on with finger to assist actual start- same effect as magnet.
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Martin Taylor
Experienced User
Username: martin_taylor

Post Number: 172
Registered: 07-2013
Posted on Sunday, 27 October, 2019 - 09:10:   Edit PostDelete PostView Post/Check IP

The magnet circuit is not needed in most climates, as Gorden mentioned the choke is bi metal.
The most common failure is from rusting trough of the heating pipes in the exhaust manifold, this causes exhzaust to come straight into the intake and overheats the choke mechanism and will cook the lubrication in the bearing causing it to stick. Test the circuit by blowing air through the tube above the choke flap and see that it only comes out via the choke (ie, not into the exhaust)

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