Running rich?

[RTanguy]

Hi,
Ive noticed for a while that Lucy sounds pretty rough and is very sluggish when first started up, and when driving and stopped at traffic lights the red ignition lights comes on and she sounds like she's going to cut out (need to rev a bit to keep her going!). She starts fine however, always first time and pretty much never needing choke. I was thinking it was just the idle speed needed adjusting but an RAC man (on a totally unrelated breakdown!) said she sounded like she was running very rich (I don't have that much faith in his opinion, I appeared to know more about the car than him!).
But anyway I checked the plugs and they are very black and sooty which I think confirms the RAC man's suspicions? (Correct me if I'm wrong!)

How is best to adjust this then? Will it have done any damage to the engine as it has been like it quite a while!
Thanks

[JOWETTJAVELIN]

Sooty plugs = running rich as you suspect. Warm the engine up fully and turn the mixture adjusting nut upwards to weaken. Turn only one or so flat at a time, revving the engine inbetween turns and listen for an improvement. Check the plugs after some miles have been covered (might want to clean them first) and note the colour - should be grey or brown round the electrodes and usually sooty round the threads anyway.

As regards damage it depends how rich it has been running - not needing any choke to start is bad news - excess petrol causes increased engine wear and the oil could be heavily diluted now.

Charge light will come on at idle as the engine isn't turning fast enough for the dynamo to cut in. As long as it goes out once you get moving all is fine.

[RTanguy]

Thanks! By upwards do you mean anti-clockwise? Just done that, turning it clockwise makes the engine sound awful so guessing its not that way! Turned it a couple of turns anticlockwise and the engine sounds far better and the ignition light has also gone off.
I'll clean the plugs at some point to make sure theres an improvement!

[Dean]

I find listening to the exhaust helps. I will twist the nut, rev the engine, walk to the back and listen to see if the phut phut phut turns into a more consistent purrrrrrrrrr. Making it weaker will raise the revs a touch, hence the light going out, so you were turning the correct way.

[MarkyB]

Clockwise as viewed from below.
Make sure the choke or cable isn't sticking first, push the choke lever down and the jet up and see if there is any change in the way it runs.

[bmcecosse]

As above - check the choke..... Running rich gives 'borewash' - which causes excessive wear to bores and piston rings.....

[MriavGraves]

Iv just tunned my suh2 carb and i done it by screw mixture nut down so it is obvious to rich hunting exhaust color. Turn one flat up rev car lift piston lift leaver untill you feel piston then lift 8 mm more if engine revs increase and keep increasing mixture to rich if engine revs decrease to weak if revs increase and settle down to what it was then mixture correct slow idle =600-800 rpm no rev counter, untill dynamo red light is flickering, choke which should be done first iv read dont quote me thow pull out 6 mm on dash set to 1000rpm

[Boomlander]

I find listening to the exhaust helps. I will twist the nut, rev the engine, walk to the back and listen to see if the phut phut phut turns into a more consistent purrrrrrrrrr. Making it weaker will raise the revs a touch, hence the light going out, so you were turning the correct way.

Quite right! I've just checked Jethro's plugs and tailpipe and they are covered in dry soot and his exhaust does indeed go Phut Phut Phut instead of purring. Also leaves a horrible stink when idling in traffic (lots of modern motor drivers turning their noses up as well as their windows ) I will definately have to tune the carb this week!

[RTanguy]

Thanks for all the replies! Ive adjusted it so it sounds a lot better, and Ive found it has really helped with the smell when idling! . Will have a more thorough look/play when Ive got more time but at least its improved for now!

[bmcecosse]

Pull out the plugs after a good run and tell us the colour of the centre insulator.

[kennatt]

check the condition of the air filter as well.

[Dean]

Thanks for all the replies! Ive adjusted it so it sounds a lot better, and Ive found it has really helped with the smell when idling! . Will have a more thorough look/play when Ive got more time but at least its improved for now!

Excellent news. Once you've sussed how it's done, it's another one of those things you'll do in two or three minutes. Done regular will keep the dreaded fuel station fill up away for longer. ;)

[RTanguy]

So, I thought I had sorted this but just tried to go out in the car after being on holiday for a couple of weeks and its really struggling to start, tried using the choke which made it a LOT worse and after getting her started she cuts out after about a minute every time. When she is running it now sounds like its idling really fast/choke is all the way out (when its not) so I'm guessing this is the choke cable sticking perhaps?
Any advice would really be appreciated because she's now stuck halfway down the drive and going nowhere!! Thanks!

[bmcecosse]

Serves you right for not taking the car on holiday with you...... Obvious answer is - check the carb to see if the 'choke' is fully off.

[RTanguy]

I'm not sure she would have made it all the way to Croatia! Sorry to be totally useless, but could you give me an idiots guide on how to do that!?

[bmcecosse]

Look under the carb and puil the choke lever to the off position. Do you have a Workshop Manual? Lots of good pictures in there.

[RTanguy]

I've only got a Haynes manual which Im trying to decipher! If I am looking at the right thing, a little arm/lever that the choke cable is attached to, it wont seem to stay down, it creeps back up after a few seconds...

[bmcecosse]

That's it - the cable must be stuck... You could try push-pull- on the cable a few time to see if it frees off. It's supposed to be pulled out and twisted slightly to fix it in place - so you could try a quarter turn anti-clock twist to see if that helps to unstick it.

[MarkyB]

Try undoing where the choke cable attaches to the carb push the lever down then do it up again.
You could even pull the choke out a fraction before you tighten it.
The curve on the choke cable needs to be as gentle as you can make it and some lubrication won't hurt either!