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rakatak · New user Joined: 04 Apr 2009 Posts: 1

Hi there, i have a pair of 34ict weber carbs on my 1641cc volkswagen beetle 1974, which i bought nearly 6 years ago and not really had any major problems with them. From time to time i adjust them to keep them running smooth.
It also has a Engle 110 cam fitted.
The one thing i notice is that the plugs keep going black and smell of fuel form the exhaust. Also between 2000-2500rpm there seems to be a flat spot when trying to drive normal but, if thrash it you can hardly notice anything.The Exhaust stays black even on long journeys.
The jets are the ones i got with the carbs as standard.
I have adjusted them to the best of my ability but regarding re-jetting i am a bit stuck.

Specifications and settings at present;

Air correction jet 160
Main jet 130
Idle jet 55 (changed from a 52 jet to reduce mixture screw to 1 3/4 turns out) Does drive a little better through gears now and
plugs are coloured abit better but, i want it perfect so what's the next move and by how much?
Pump jet 40

Speed screw 2 1/2 turns in from base
Mixture screw 1 3/4 turns out.

Ignition timing set at 10deg btdc
Have checked float settings
Fitted fuel regulator

Has also a balance pipe across both manifolds, otherwise it does not run smooth at all.Do i need this pipe?
I do approx 1000-1200 miles pa, sometimes less.

Please can you advise me of anything i can do to solve this problem, including changing jets etc.Please be specific as possible so i do not need to buy jets that are not required, however i am grateful if you can help or advise.

Thank you.

Ash