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Rodney Peach
Experienced User
Username: rodney

Post Number: 93
Registered: 12-2003
Posted on Sunday, 04 August, 2019 - 01:51:   Edit PostDelete PostView Post/Check IP

Hi All,
I have another issue ! as car is stored a lot I Had to dismantle carbs and clean etc ! but its running rough I thought it was all the same thing when its cold it takes 10-15 mins to get it to idle with foot on accelerator pedal without moving foot car up and down revs poping exhaust terrible and like missing then suddenly it sort of clears like something switches or clicks or frees ?? no noise of course just seems like that ! and goes back to auto choke high revs kick pedal and revs normal and idles normal but rough like missing , but at this stage car it hot ??

Has anybody had this problem or can advise ?

Regards
Rodney
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Richard Greene
Experienced User
Username: benzjag

Post Number: 163
Registered: 12-2012
Posted on Sunday, 04 August, 2019 - 04:05:   Edit PostDelete PostView Post/Check IP

Rodney,

I had the same problem several years ago on my 78 Shadow. There is a thread on it in the archives entitled "78 Shadow Starting/Choke Problem". I found it, but I can't find out how to link it!

Long story short, it was the solenoid pictured. It can be cleaned, but I replaced it with another one. I understand a Jaguar solenoid can be substituted. I also adjusted the choke spring which is behind the black "stove pipe" housing (pic). It works just like the Chevy carb choke spring. I adjusted the spring turning it right/left until the flap was almost closed when cold.

Richard

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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2903
Registered: 06-2009
Posted on Sunday, 04 August, 2019 - 04:36:   Edit PostDelete PostView Post/Check IP

Richard,

I believe you must be referencing the topic you started:

http://au.rrforums.net/forum/messages/17001/17144.html

And the solenoid to which you're pointing in that photo is the anti-run-on (AKA anti-dieseling) solenoid and if it's stuck open it is hellish to keep the car running at all.

Weakener & Anti-Run-On Solenoids

Brian
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Richard Greene
Experienced User
Username: benzjag

Post Number: 164
Registered: 12-2012
Posted on Sunday, 04 August, 2019 - 04:42:   Edit PostDelete PostView Post/Check IP

Brian,

Yes!

The pic is EXCELLENT!

Richard
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2904
Registered: 06-2009
Posted on Sunday, 04 August, 2019 - 05:12:   Edit PostDelete PostView Post/Check IP

By the way, I had almost precisely these characteristics on LRK37110 upon her acquisition, and it was the anti-dieseling solenoid stuck in the open position.

I removed and lubricated the solenoid, cycling it many times by hand (with a direct connection to the car battery) after it had had sufficient time for the WD40 (or similar penetrating lubricant) to soak. It has been functioning just fine ever since.

I know I have to have started a topic about this on this forum, but I'll be darned if I can recall anything specific enough to allow me to pull it up quickly.

Brian
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 478
Registered: 05-2016
Posted on Sunday, 04 August, 2019 - 08:25:   Edit PostDelete PostView Post/Check IP

I had a similar problem when my Silver Shadow 11 engine was cold, it would misfire and the revs would rise & fall at random but the engine would settle down once it warmed up. Turned out to be a very simple fix, the vacuum hose just to the right of the B-bank carb that goes to the weakener solenoid had become detached causing a serious vacuum leak. One I reattached the hose the engine ran perfectly again. At the same time I also squirted plenty of WD40 into the weakener solenoid so that could also have been a factor too.
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Hubert Kelly
Frequent User
Username: h_kelly

Post Number: 356
Registered: 03-2012
Posted on Sunday, 04 August, 2019 - 18:29:   Edit PostDelete PostView Post/Check IP

Rodney,
when you turn ignition off, does the engine have a slight run on?.
You mentioned you cleaned carbs , did you take off dash pots , clean and lube?.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 94
Registered: 12-2003
Posted on Monday, 05 August, 2019 - 02:14:   Edit PostDelete PostView Post/Check IP

Hi Hubert ,
no running on no ! yes carbs off totally clean and necessary parts but not running smooth at all apart from all other problems .

Regards
Rodney
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2908
Registered: 06-2009
Posted on Monday, 05 August, 2019 - 04:25:   Edit PostDelete PostView Post/Check IP

Rodney,

Which is an even stronger indication that you probably have the anti-run-on solenoid stuck in the open position.

The rough running and having to fight to keep it running by having the accelerator depressed far more than you think you would is because that solenoid being open is causing a constant vacuum to be exerted on the fuel source which is normally meant to cut it off, entirely and quickly, to prevent dieseling.

I once had the opposite issue (stuck closed) on SRH33576 and not only had dieseling but the engine turning backward during that process. Not pleasant nor good in any way.

Brian
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Hubert Kelly
Frequent User
Username: h_kelly

Post Number: 357
Registered: 03-2012
Posted on Monday, 05 August, 2019 - 07:22:   Edit PostDelete PostView Post/Check IP

Rodney,
when you start the car (or turn ignition on) does then fast idLe come on?.
Have you removed the air intake pipe to see if auto choke is coming on?.
The flow of petrol , bilaterally is good to each carb?.
Your car's symptoms are similar to my own 79 shadow, it turned out to be carbon build up on the dash pots , preventing the carb piston from moving ,causing terrible running ,no power etc etc, dash pots cleaned and oiled ..perfect since (touch wood)
P's the dis cap and rotor arm are clean?.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 97
Registered: 12-2003
Posted on Monday, 05 August, 2019 - 18:37:   Edit PostDelete PostView Post/Check IP

Hi Hubert ,

I normally floor accelerator pedal so the choke sets then try and start sometimes choke on sometimes no ! the choke lever flaps up and down but I checked the part which is a magnet it works Ok, yes I am trying all things carb is clean oil in pots its missing a little too so was going to change spark plugs but do not know which to put in ? the ones that come in handbook do not exist they say here in Spain RN17Y what other references or makes be OK? as I want to change them on all my rolls corniche shadow and spirit .

Regards
Rodney
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Hubert Kelly
Frequent User
Username: h_kelly

Post Number: 358
Registered: 03-2012
Posted on Monday, 05 August, 2019 - 19:04:   Edit PostDelete PostView Post/Check IP

Hi Rodney, when my 79 shadow gave trouble ( ie dash pots) the plugs were filthy , oiled up etc, particularly on one side, probably the side piston carbon stuck. If not to old, a good clean might do the job.I got my new plugs at flying spares at approx 2 UK pounds each.
Anyhow I'll check the plug number on my car and report back layer
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Hubert Kelly
Frequent User
Username: h_kelly

Post Number: 360
Registered: 03-2012
Posted on Tuesday, 06 August, 2019 - 04:22:   Edit PostDelete PostView Post/Check IP

Rodney,
The plugs on my 79 shadow are NGK(R) BPR5ES.
Regards
Hk
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2134
Registered: 05-2012
Posted on Tuesday, 06 August, 2019 - 05:37:   Edit PostDelete PostView Post/Check IP

Rodney

I use the same plugs as Hubert. Spark plugs were a discussion topic a while ago and the consensus was these were the best standard priced plugs to use.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 101
Registered: 12-2003
Posted on Wednesday, 07 August, 2019 - 05:23:   Edit PostDelete PostView Post/Check IP

Hi Hubert and Geoff .

I will get these plugs then if they are good !

Thanks Again
Rodney

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