I bought my 1980 L82 6 months ago. It had an old rebuilt carb on it and its was junk! One of the problems was that after I drove the car and parked it for more than 15 minutes it was hard to start and when it did it blew out Black smoke. I had a new Edlebrock Thunder Series carb put on along with a performance series intake. The car runs super, however the same problem is still there. As long as I start the car before it has sat for 15 minutes it will start just fine, after 15 minutes its crank crank crank and then Black smoke! Edlebrock told me to check my fuel pressure. It was about 7 lbs so I put a fuel regulator on it. No differance. I have a heat insulator gasket between the intack and carb but I am wondering if it is enough. I was also told to check my heat risor valve. I discovered that someone has welded it in the 3/4 closed position. I am guessing that the flapper is gone or other wize you would think the car would be running bad. If it is cold or if I open my hood after a drive then the car is fine. Does anyone one have a solution?

 

Both carbs are leaking and flooding the engine, or maybe the choke and pull off isn`t adjusted correctly

 

do a compression test, if it wont start hot thats the first thing I would check. good luck.

-alex

 

I have done a compression check and that was OK! Someone else mentioned the fact that the carb might be leaking. He told me to turn each jet off and if it still was trying to run then I was leaking fuel. As soon as the last jet was screwed in it died. We had some cold days there for a while and I was driving the car without a problem. When I park it and let it sit for a while, and it is hot out, you can start smelling gas after about 5 minutes. Back when I did the fuel pressure check I noticed that after I removed the gauge from between the carb and fuel pump that there was millions of air bubbles in the line. The gas would also keep rising and slowly spilling out of the line when it was in the up-right position. I watched this for 45 minutes at which time the air bubbles had gone down to a bare minimum and the gas was'nt rising anything like it was but still rising some. I checked my return line to the tank and it was clear. I also unscrewed the gas cap during that time. What do you think about the heat riser or the gasket? Edlbrock offers a 1/2" thick heat gasket and the one I have is only about 1/8" thick. Its driving me crazy!!!! Mark.