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Carburettor Balance


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I have sorted out fuel pump problems, now a new challange!

I have run the engine but it is obvious from the colour of the exhaust manifolds that cylinders 1 & 2 are not working. The engine is also quite rough. (1800 Zetec on twin 40's)

I have read that this needs a adjustment to the carb balance and no doubt this will be done when i get the car finished and to a tuner, but in the meantime would like to make it better than it currently is . Can anybody advise me which screws to adjust - For reference theres a drawing of DCOE40 on the following link if this helps.

Weber 40 Drawing


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Dave Andrews has an excellent page on DCOEs: http://hometown.aol.com/DVAndrews/index.htm

Basically you need to adjust the linkage mechanism between the two carbs to start with.  Try raising the revs slowly between idle & 3k.  As it picks up you'll hear it running roughly.  Make adjustments on the linkage screw in small increments (.25 - .5 turns) at idle and listen to hear if the airflow is smoother/rougher.  A short piece of hose between your ear and the carb trumpet will help you hear what's going on.  Tweaking the revs up can help in hearing how each carb picks up.  Once your satisfied you have a reasonable airflow balance follow the instructions on the above link (screw down then screw out adjusters 2.5 turns)

The idle mix is #56 on your diagram



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Thanks Jess, the site was V useful.

As I adjusted the balance the engine has stopeed rocking and I've had to lower the tick over significantly. I won't bother with the air balance adjust as the car will be tuned and a throttle position sensor for 3D added before the car goes for SVA. (it'll take 1 month or so to finish build) I just wanted to make it run right as it was driving me mad before



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