Marias yellow Murena 1,6 has a little problem - when we were on trip with our Murenas, and she was ahead, I saw a black smoke from exhaust everytime when she started to overtake somebody. I changed the sparks, air filter and at least the exhaust muffler. I also have prepaired new spark wires, but don't think that it will help. At small rews or idling, it's OK. Something wrong with fuel level in carburetor? Or some jet is worn so much???
If it is only going rich when initially accelerating hard, and the mixture / gas analysis shows correct mixtures otherwise, then look to the pump jet system delivering too much fuel, Michael.
Roy
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