carbed gta rough running when cold

hi i am from canada,great website! i have a 1985 gta with the 2barrel and one barrel carb setup,when i start the car cold it is very rich until it warms up and then its better,can anyone give me any advice on adjustment,etc? thank you

i have a 1985 gta with the 2barrel and one barrel carb setup,when i start the car cold it is very rich until it warms up and then its better,can anyone give me any advice on adjustment,etc? thank you

Hi senna
The carbs are quite complicated on these Atmo`s, might I suggest you read all about them, before you start playing with them. Clearly it is very difficult to pinpoint your problem. Might I suggest you read the relevant pages of the manual which you can download from this site by clicking on "Technical Help" in the LH index, then "Alpine GTA" then "GTA Manual" then "Engine", then read B29 throu B41.
Hope this helps
John

hi there,
yes I had some probs with my Atmo carbs, which are triple Solex's, are yours the same? I have mine very good now, or seem to be... did have to learn them a little before I got them right...

What is the spark plug colour like? Have you looked? Maybe a good starting point

thank you,i will check

Yes Senna, plug colour.. what is it... abit white looking? or black?
or a nice sand brown colour?
Sand Brown is what is good... black too rich(petrol)... white too lean(air)...

problem is as there is two carbs... the first carb does the low speed/ startup... when you are going 0-40 mph or (0-60kmph) think the doubles then kick in (about 60-70kmph?).... think I am right in saying that?
Maybe JohnC can confirm?

Yes, it could be that your first carb is of bad adjustment or either of the doubles... I have info on both of these if needed... They are not too hard too learn, well that's what I found after abit of experimentation..

also a good starting point, read about the carbs in manual and maybe also clean all the jets before starting adjustment... they can pick up muck as they suck pretty hard when you put your foot down.. have you got any flaky paint etc in air filter cover/ box...?

if so clean it all out/ (paint remover) and respray with a good heat resistant paint.... What is your air filter looking like? Dirty? Clean?

You can clean it or get a new one if looking blocked?
Anyway, don't want to overload you with info but just trying to help as had similar issues... regards...

problem is as there is two carbs... the first carb does the low speed/ startup... when you are going 0-40 mph or (0-60kmph) think the doubles then kick in (about 60-70kmph?).... think I am right in saying that?
Maybe JohnC can confirm?
.

Hi all.
Just checking in from Leipzig, Just for info, you are right in principal, that the single carb does the gentle running around but the twin barrels come into play when you put your foot down and the depression in the manifold is released, there is no mechinical connection between the accelerator pedal and the twin barrel buterflies, if you read the manual on how they operate, it is a bit confusing as the butterfly actuator operates completely opposite to what you might think. I have explained this elsewhere a few months ago. The other point I must add is there is really very little you can do with fixed jet carbs, appart from setting the idle mixture, which as I explained before is just setting it for max revs at idle, then adjust the revs with the other larger adjusting screw, which will not change the mixture while adjusting the idle rpm. I would not adjust any linkages if they have not been disturbed. By all means make sure the carbs are clean and jets are clear. Fixed jet carbs are what they are, Fixed jet.... But remember once the car starts to move, the mixture adjustment has no part to play in the operation of the carb. Hope this helps.
JohnC