Guys - I got a reasonable response from DeVrou:
I am sorry to hear that you are having problems with your kit. First, try the new carb and if you are still having problems, let us know as we will do our best to get the problem resolved. I personally don't think that it is the magneto because it is getting spark and running, just not right. It sounds like a fuel delivery problem to me and I hope that the carb will take care of it. Also try running with the fuel cap loose or off to make sure that you are not getting a vapor lock that prevents the fuel from flowing. Check the filter in the fuel petcock to see if it is jammed or dirty. If so remove it and buy a $2 inline fuel filter to put in the fuel line. Also, check your needle in the bottom of the carb cylinder to make sure that there is not dirt or debri in there that is keeping it from sliding up and down properly.
We'll do our best to make it right.
Have a Great Day,