I wish I knew more about carb's. I had it rebuilt by a reliable shop who put an electronic choke, a new vac advance, and checked the carb twice for me after the job. I told them of the fuel smell and they said there was oil leaking through the rings causing the spark plugs to burn oil while the car ws starting. To me that didn't explain the heavy gas smell? Occasionally if the car is hot it will get a puff of white smoke and then run fine. Any ideas?