Thread: black sooty plugs?

Seeing you talk of "carby" and not "carbies" , I assume you have some bogus setup like a Holley,or Rochester. The standard strombergs are very reliable and only go rich if very very worn.
So no one who is expert in Rovers can help. You have to find someone who knows about Holleys or whatever.
This should not be too hard. Go to a speed shop or speedboat shop and ask around.
Regards Philip A

<span style="color:blue">have you checked the float level is correct....?</span>

Sorry I should have said carbys, not carby. my mistake they are strombergs, (175 cd-2)
I'm not sure how to check the float level I'll have a look in the manual tonight.

<span style="color:blue">have they got enough oil in the dampers...?</span>

OK, we have established you have CD175s.
When you say you adjusted the mixture, where did you adjust it???

On most OZ carbs, the mixture can only be adjusted with a special tool which goes down the dashpot. Did you do this?
Very early cars have the adjustment under the float bowl, by raising or lowering the main jet. In any case , 8 turns is far too much and good carbs would not run at extremes like that.

I am concerned about the "auto choke converted to manual". Strombergs do not have a choke they have an enrichening circuit on one carby which also feeds the second/. I am wondering how it was converted to manual, with parts from an earlier carb? This could be the problem.

The main reasons for rich running are
1 float level too high/needle and seat worn out
2 main jet and needle so worn that cannot get close enough for lean mixture.
3 Maybe diaphragms broken on one or more carbs. have you checked these? But the car would hardly run.
Really there is not much else that can go wrong!
regards Philip A

Originally posted by PhilipA


On most OZ carbs, the mixture can only be adjusted with a special tool which goes down the dashpot.

[b][size=18]<span style="color:blue">which should look something like this......</span>

[quote=DEFENDERZOOK]<span style="color:blue">have they got enough oil in the dampers...?</span>

re: oil, Yes, about 10-15mm from the top.


PhilipA wrote:
On most OZ carbs, the mixture can only be adjusted with a special tool which goes down the dashpot.

I bought one of those "special tools" eg : expensive allen key.
to adjust the mix through the neck of the dashpot.

8 turns is far too much and good carbs would not run at extremes like that.
I guessed it would be I tried settings in between but I wanted to try the extremes to see if it would make any difference, it ran a bit better the leaner but that was it, still sooty, (no, not the puppet).

"auto choke converted to manual".
Not knowing a lot about these carbs I'm not sure, I took it to a mechanic once a while ago and he said " Someone has converted these to a manual choke. So sorry I couldn't really say.

Maybe diaphragms broken
Two new diaphragms


1 float level too high/needle and seat worn out
2 main jet and needle so worn that cannot get close enough for lean mixture.

Option 1 & 2 is worth checking
Looks like I'll be thumbing through the manuals over the weekend.

<span style="color:blue">if you undo the four screws....the top half should come off....
then you can check the diaphragm......</span>