Quote:
Originally Posted by Archrms
The exhaust is slightly dark, and smells of gas (rich), with black soot in pipes. Just had carbs tweaked, everything adjusted except for power valve. Just wondering if this could be the cause of the rich exhaust fumes.
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I would first adjust the idle mixture screws. Turn them in (Clockwise) about 1/8 turn and see what the idle is like. This should lean out the rich condition at idle. It would help to have a good vacuum gauge hooked up when making the adjustment. Many people say that the idle screws should be about 1.5 turn off the seats for best idle mixture, but the 750 cfm carb on my Cobra runs best at 3/4 of a turn off the seats. If it improves the idle, adust the screws cw a little more and see what happens.
Of course, I'm assuming that the power valve is NOT bad. And adjusting the idle screws are quick and easy adjustment as compared to disassembling carbs.
I'm also assuming that the floats are adjusted properly, and not set too high so that gas spills out of the bowls at idle.
You said that you just had the carbs tweaked. Was this done while the engine was running? Hopefully the person doing the tweaking is a good tuner.