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Randy Roberson
Frequent User
Username: wascator

Post Number: 852
Registered: 05-2009
Posted on Monday, 27 December, 2021 - 05:46:   Edit PostDelete PostView Post/Check IP

Hi, Iíve been away for a while, preoccupied by Ford Model Ts and Pierce-Arrows, so I am behind on my RR work.
I got in the Ď77 to move it and the shifter motor is balky. I can fiddle with the shift lever and get it to work, but it obviously needs contacts cleaned or some sort of maintenance.
Also, it will start right up but idles poorly and has low power with back-spitting when pushed at low speeds, like itís lean. I swear I cannot see an adjustment on the two SU carbs, like I can see on the 1970 Shadow. Please advise on either issue as I cannot go out amongst the common folk like thisÖ
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 3255
Registered: 06-2009
Posted on Monday, 27 December, 2021 - 06:57:   Edit PostDelete PostView Post/Check IP

Randy,

With regard to the Carb, it is very well worth your time to have a look at and thorough read through Chapter U5 in the Shadow II/T2 workshop manual.

Figure U29 shows you the adjusting screw location behind a tamper-proof cap, which must be removed. There may be other adjustments you might want to try first.

Brian
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Larry Kavanagh
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Username: shadow_11

Post Number: 810
Registered: 05-2016
Posted on Monday, 27 December, 2021 - 06:59:   Edit PostDelete PostView Post/Check IP

The twin SU HIF7 carbs are set at the factory and usually don't need any adjustment other than balancing them. The mixture adjustment screw has a tamper proof cap to discourage fiddling. It sounds like you have either a manifold leak (maybe at one of the hoses)or possibly crud in the carb float chambers or clogged fuel filters. There are 3 fuel filters (one small one at the carb end of the fuel feed pipe to each carb) and a main fuel filter under the car. Sticking dashpot pistons is another possibility, have you topped up the dashpot oil ?
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Randy Roberson
Frequent User
Username: wascator

Post Number: 853
Registered: 05-2009
Posted on Monday, 27 December, 2021 - 07:19:   Edit PostDelete PostView Post/Check IP

As a matter of fact, I think the dashpot oil in one or both carbs is gone; why I donít know. I remember finding one low past time I studied this, and adding some. I will have to refresh my memory in the Manual before further proceedings.
Itís great to get back and catch up on all the Forum happenings.
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Mark Aldridge
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Username: mark_aldridge

Post Number: 765
Registered: 10-2008
Posted on Monday, 27 December, 2021 - 07:57:   Edit PostDelete PostView Post/Check IP

Randy, check the mixture weakener is not stuck on all of the time. Had a similar problem with my Shadow1 ( different weakener set up )and also the 1982 Mulsanne which I believe is similar to the Shadow2 set up. Mine are UK cars.
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 2484
Registered: 09-2004
Posted on Tuesday, 28 December, 2021 - 20:49:   Edit PostDelete PostView Post/Check IP

And not forgetting the Opus distributor starting to fail!
Classic signs of the reluctor etc failing, starting ok then misfires as it gets warm with eventual FTP.
When cold all is well again on the initial start up.
Scope to test.
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Randy Roberson
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Username: wascator

Post Number: 854
Registered: 05-2009
Posted on Saturday, 26 March, 2022 - 06:14:   Edit PostDelete PostView Post/Check IP

At least the Opus is gone; replaced with a Pertronix unit several years ago.
Weakener valve is a good idea; thanks!
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 2527
Registered: 09-2004
Posted on Saturday, 26 March, 2022 - 20:27:   Edit PostDelete PostView Post/Check IP

If the Pertronix is ok then maybe the ballast is failing if fitted!
Have also known coils to give problems as you state.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 3274
Registered: 06-2009
Posted on Sunday, 27 March, 2022 - 07:20:   Edit PostDelete PostView Post/Check IP

Definitely check *both* solenoids - weakener and anti-run on.

The anti-run-on solenoid on LRK37110 had gotten sticky at one point and stayed stuck open. The behavior was much like your description.

Brian
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Randy Roberson
Frequent User
Username: wascator

Post Number: 858
Registered: 05-2009
Posted on Friday, 08 April, 2022 - 13:23:   Edit PostDelete PostView Post/Check IP

My anti run-on solenoid has 12 V from either wire to the metal housing but zero V between wires, all with ignition on; also no click from ignition off to ignition on and back.
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Randy Roberson
Frequent User
Username: wascator

Post Number: 867
Registered: 05-2009
Posted on Tuesday, 26 April, 2022 - 02:51:   Edit PostDelete PostView Post/Check IP

I have satisfied myself the anti-run on solenoid is bad, so I have ordered a replacement. It has a significant value as a core so don't just toss one if you have a bad one.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 3284
Registered: 06-2009
Posted on Wednesday, 27 April, 2022 - 01:59:   Edit PostDelete PostView Post/Check IP

Randy,

It's also very common for both of these solenoids to "become sticky" from years of dirt and no attention.

In a very great many cases, giving the inside a good shot of WD40 or similar (pick your penetrating light lubricant of choice, I have used others, too) then letting it sit for a day or two before hooking it up to a test lead and activating/deactivating it will often cause the mechanism to spring back to life and remain that way for many years afterward.

I replaced both on SRH33576 but revived one on LRK37110.

Brian
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Randy Roberson
Frequent User
Username: wascator

Post Number: 868
Registered: 05-2009
Posted on Friday, 06 May, 2022 - 00:22:   Edit PostDelete PostView Post/Check IP

Additional question: what size are the rubber vacuum hoses associated with the anti-run-on and weakener systems? Mine are hard as Chinese arithmetic and need to be replaced. I tried 5/16th inch fuel line but the fit on the metal barbs is slightly loose.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 777
Registered: 11-2017
Posted on Friday, 06 May, 2022 - 01:14:   Edit PostDelete PostView Post/Check IP

You can solve the loose factor with a short piece of shrink tubing over the metal tube. It may take a second layer until snug. You can also buy small pinch clamps, but best to have a snug fit to start.
Measure the diameter of the metal tube with a caliper and you will find it is best to use tubing sized in millimeters.
Nothing wrong with hard vac hose as long as it doesn't have to move and is tied down accordingly.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 3288
Registered: 06-2009
Posted on Friday, 06 May, 2022 - 02:45:   Edit PostDelete PostView Post/Check IP

Randy,

If this is not time critical I can check the silicone vacuum tubing I used, but not right now.

I had a total right knee replacement yesterday so my mobility is, shall we say, limited at the moment and will be so for a bit.

Brian
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Jeff Young
Frequent User
Username: jeyjey

Post Number: 463
Registered: 10-2010
Posted on Friday, 06 May, 2022 - 02:51:   Edit PostDelete PostView Post/Check IP

I hope you're on the mend quickly, Brian.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 3289
Registered: 06-2009
Posted on Friday, 06 May, 2022 - 03:31:   Edit PostDelete PostView Post/Check IP

Thanks Jeff.

This has, at least so far, involved a lot less pain and discomfort than I had anticipated. But, today is my first outpatient PT session, so fresh hell awaits!

Brian
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Omar M. Shams
Grand Master
Username: omar

Post Number: 2194
Registered: 04-2009
Posted on Friday, 06 May, 2022 - 04:54:   Edit PostDelete PostView Post/Check IP

All the best for a speedy recovery Brian.
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2312
Registered: 05-2012
Posted on Friday, 06 May, 2022 - 08:14:   Edit PostDelete PostView Post/Check IP

Best Wishes for a quick recovery Brian.
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Graham Phillips
Frequent User
Username: playtime

Post Number: 485
Registered: 03-2019
Posted on Friday, 06 May, 2022 - 09:15:   Edit PostDelete PostView Post/Check IP

G'day everyone,...


Sorry to hear about you needing a knee replacement.

I do hope your recovery go's better than me when I

rolled my ankle, then a week later just when I was

able to walk again I did it again only this time I

got a hairline fracture in my ankle bone.

I am only now mobile again.

Get better Brian.

Don't be like me!


Graham.
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Randy Roberson
Frequent User
Username: wascator

Post Number: 870
Registered: 05-2009
Posted on Tuesday, 31 May, 2022 - 23:02:   Edit PostDelete PostView Post/Check IP

UPDATE: examination of the '77 Silver Wraith II's anti run-on and weakener solenoids, revealed a chafed wire lead on the anti run-on solenoid, so I obtained a used replacement. This made no difference in the wonky engine performance, though: Engine starts easily and runs OK until the choke starts opening, at which time it starts to chuff intermittently in the exhaust. Manual manipulation of the choke toward closed will instantly make this stop. In driving it is way down on power and chuffs very noticably, such that it is hardly drivable.
I wonder if one carb could be blocked or dry of fuel...
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Jim Walters
Frequent User
Username: jim_walters

Post Number: 365
Registered: 01-2014
Posted on Wednesday, 01 June, 2022 - 03:45:   Edit PostDelete PostView Post/Check IP

Pull the hoses off the float bowl vents and see if it runs OK then. Carbs are way lean or you have a big vacuum leak, which is likely related to the anti run on solenoid. On the HIF's it's easier to pull the float bowl vent hoses off the weakener assembly than remove them off the carb body.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Jeff Martin
Frequent User
Username: jeff_r_1

Post Number: 367
Registered: 07-2018
Posted on Wednesday, 01 June, 2022 - 04:01:   Edit PostDelete PostView Post/Check IP

I don't own a Shadow and my advice comes from what I've learned here on this forum and the US one.
You have to take the weakener system off the table and eliminate that as the problem, you're just throwing parts at it right now.
Disconnect it at the float bowls and block off the weakener system so not to create a vacuum leak, leave the connection open to the atmosphere at the floats.

Find where the weakener system connects onto the intake manifold and disconnect that _ plug off the port into the intake manifold that the weakener system was connected to.
Technically because you disconnected it from the intake manifold you don't have to block it off where it was disconnected from the float bowls, but do it anyway.

Take it for a drive and see if the problem is solved.

If it still does it, then you may assume it's not the weakener system, but even then from the sounds of things, all the vacuum lines are hard and probably cracked and need replacing. They may be leaking, also assume that any joints in the vacuum lines may be cracked.
Inspect all the lines carefully, replacing them one at a time _ do not pull all of them off at once.
Sticky dirty solenoids is another problem as mentioned earlier.

Note that having no oil in the damper tubes will not cause poor running over-all. All that does is keep the engine from getting a big gulp of fuel when your foot gets heavy _ you will get poor fuel economy, and that's it.
Having to ad oil is normal, the engine use it up as it leaks out the bottom of the damper tubes.

With all that said, don't start messing with the mixture until you have taken everything else off the table, there is no reason for the mixture to suddenly go out of adjustment.
It sounds lean, so the weakener system has to be dealt with first.

Also check the dash pot pistons and make sure they rise and fall smoothly, sticky pistons will also cause your problem.
This was also mentioned earlier in the thread as well as other things like dirty clogged fuel filters and such, but you have to eliminate the weakener system as the cause first.
Keep in mind too that it may be that and other things as well, but my disconnecting the weakener system you will have a place to start.

Purchasing an inexpensive vacuum pump takes the guess work out of finding vacuum leaks.
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Randy Roberson
Frequent User
Username: wascator

Post Number: 871
Registered: 05-2009
Posted on Thursday, 02 June, 2022 - 23:59:   Edit PostDelete PostView Post/Check IP

All good advice and the things I am concentrating on. I replaced the anti-runon solenoid because the wire was chafed and it was intermittant, depending on moving the wire. That said, there was no air entering the weakener system because I have the filter disconnected and the hose plugged. Vacuum leak(s) possible of course. Exactly what it seems like, just have to find it.
I do not plan to touch the mixture as it is not likely the issue. Engine ran fine but something happened suddenly, just have to find it.
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Trevor Hodgekinson
Frequent User
Username: wm20

Post Number: 286
Registered: 11-2006
Posted on Friday, 03 June, 2022 - 14:02:   Edit PostDelete PostView Post/Check IP

Working on the ago old adage
50% of fuel problems are caused by ignition faults while 50% of ignition faults are routed in the fuel supply .
Suddenly = bad HT lead - bad plug - bad dizzy cap
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Randy Roberson
Frequent User
Username: wascator

Post Number: 872
Registered: 05-2009
Posted on Thursday, 09 June, 2022 - 04:37:   Edit PostDelete PostView Post/Check IP

Very possible of course.
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Randy Roberson
Frequent User
Username: wascator

Post Number: 874
Registered: 05-2009
Posted on Saturday, 11 June, 2022 - 07:36:   Edit PostDelete PostView Post/Check IP

Today I tried a different ignition coil; no change.

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