| Author | Message | ||
     Alexander hoar Yet to post message Username: plumber Post Number: 1 Registered: 4-2016 |
Hello I have a silver shadow 2 I have been having trouble with rough idle so I decided to check the plugs . Thery were heavily carbon up I only change them about 6 months ago Would this indicate the mixture too rich or faulty weakener solenoild Thanks for any help Alec | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1523 Registered: 6-2006 |
Hi Alec, Can you post pictures of them? Are they all the same? Have you being using the car for motorway. Local journeys. Running it stationary? Cheers, Paul. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1000 Registered: 9-2004 |
Hello, do you have any blue smoke on the overrun, down hills etc. If so this would point to worn piston rings or more common fault of inlet valve seals. | ||
| Alexander hoar New User Username: plumber Post Number: 2 Registered: 4-2016 |
Hello Paul Thanks for the reply Unfortunately I've clean them up now No not all were sootted up its mainly A1,A2,A3, A4 I'ts mainly been running in stationary Would an over rich mixture ie the jet height too low in the carb cause the sooting Thanks Alec | ||
| Alexander hoar New User Username: plumber Post Number: 3 Registered: 4-2016 |
Hello Patrick No blue smoke on runs It's had the problem for a while and in the past I've either cleaned the plugs or changed them The plugs seem to constantly build up with soot over a short period of time then the car's idle seems more lumpy Thanks Alec | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1524 Registered: 6-2006 |
Running stationary is never good for these old cars. The plugs listed are fed from different carbs so probably not just a mixture thing. Until the car is driven 'properly' and in normal use it's impossible to know where you are going with it. New plugs and some nice drives and see what happens to them then. | ||
| Alexander hoar New User Username: plumber Post Number: 4 Registered: 4-2016 |
Thanks Paul My mistake with the plugs old age has set in It was all the plugs in A bank The reason for asking about the jet height was my son adjusted the mixture with a colour tune spark plug a while back and the jet seems low ? Its the right hand carb looking from the drivers seat Which as I understand feeds Those plugs So I was trying to work out if the jet was too low and running rich was cause sooting on the plugs I will get some new plugs and give her a day out Thanks Alec | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1525 Registered: 6-2006 |
A1 B2 B3 A4 B1 A2 A3 B4 are how the carbs feed the cylinders. Cheers, Paul. | ||
| Alexander hoar New User Username: plumber Post Number: 5 Registered: 4-2016 |
Thanks Paul As you say it can't just be mixture then So each carb feeds two plugs from Bank A and B and as all the plugs in bank A were sooty it can't simply be a mixture problem I'll take it out for a run with some new plugs Thanks again Alec | ||
| David Gore Moderator Username: david_gore Post Number: 2038 Registered: 4-2003 |
Alexander, It is time to resurrect my "happy weekend" tune up for R-R V8 engines that have spent too much time on short trips and/or idling in stop/start city traffic. This procedure involves the following: 1. Select a country holiday resort at least 400Km [250 miles] linked by a highway/motorway to your home where you can maintain continuous speeds in excess of 100Km/hr [60mph]. 2. Book at least 1 night's accommodation 3. Time your travel to be undertaken as soon as possible after a scheduled engine oil change and spark plug replacement. Drive continuously to and from your destination. Enjoy your time there appropriately. 4. You will notice some changes in engine performance as you get closer to your destination - the engine will be smoother and more responsive. 5. Further improvement should become evident on the return trip. 6. Try to take the car on a long trip [i.e. at least two hours continuous high speed driving] every few months to keep the engine responsive. This is my version of the traditional "Italian tune up" which I consider to be more appropriate for a R-R/B custodian . | ||
| Bob Reynolds Grand Master Username: bobreynolds Post Number: 389 Registered: 8-2012 |
It could still be the mixture. Surely your son adjusted both carbs and not just one? Perhaps he didn't realise which carb fed which cylinder, as it's not obvious. Colourtune is usually quite accurate, but it can only show you the mixture at idling speed - not when running. I find it a lot more accurate than relying on the lifting pin and listening for a rise in revs. | ||
| Alexander New User Username: plumber Post Number: 6 Registered: 4-2016 |
Hello David that sounds like a very good idea Hello Bob Yes he adjusted both carb jets He did say that they seemed a bit low .When you start he set them level with the bridge and then 1/4 turn to lower them as a starting point Is there a height you should expect the jet to be set at ? so you would know outside this height you would know it's going to run a bit rich or lean Thanks Alec | ||
| Bob Reynolds Grand Master Username: bobreynolds Post Number: 391 Registered: 8-2012 |
The Shadow1 manual says to lower them 2 turns as a starting point. (Page k20) 1/4 of a turn would be much too lean and I am surprised the engine would run at that setting. The Shadow2 manual says to lower the jet 3.05mm. That seems about the same as 2 turns. (Page k5-29) | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1528 Registered: 6-2006 |
You really need to check the plugs after a run. Don't go by measurements except both sides are usually the same. The jet is mounted on a bimetallic strip which adjusts it's height to compensate for hot or cold petrol. How the engine idles is the most important test. When you start a car the plugs will soot up. When you drive it the soot gets burnt off. Every carb RR will soot up the plugs if just run in a garage . . unless you run it up to temperature and then at over 2000 rpm for at least 10 mins . That may keep your plugs clean but I would not recommend doing it in practice. Take her for a drive and check the idle on return. Then check the plugs once cooled down. If they are black and sooty then , you may have a problem. Enjoy the drives  | ||
| Alexander New User Username: plumber Post Number: 7 Registered: 4-2016 |
Thanks Paul It's time to take her out on that maiden voyage Thanks Bob I will tell my son it's two turns he is normally ok at reading the manual but does have a habit of speed reading ie only reading what he wants Thanks Alec |
