Not to say this is your problem but I'm running dual Webers, and shortly after initial startup it started smoking.I went thru a lot of checks until I looked down the carburetors and both were slobbering gas down the throat at idle. My new (Chinese) fuel pump was putting out too much fuel pressure. I put a regulator in and that took care of it for a couple of days. Then it started smoking again and I found both idle jets were plugged. The Webers seam to be very sensitive to small particles in the gas. I have since installed 2 gas filters and it still does every once in a while. When it starts smoking I remove the jets and blow them and it stops smoking.
