While I'm waiting, (I'm subbing a High School Art class, so I'm free to surf), just wanted to mention that since our last conversation, I did adjust the air screws properly, and it's a 1/2 turn out with 1 larger pilot jet. It starts and idles great, but I don't need to choke it. But,...
It still backfires! I have a set of butterfly shaft seals, but I've been putting them off because they are buggars to remove. At the same time I'm putting the original pilots back in since my plugs are reading too rich.