Had sort of the same problem of getting car to idle. I ended up having to adjust the secondary butterflies. only cracked them a little and it took care of problem.
Thanks. I'll try that, but I'm still worried about it going backwards.
I went out and richened it a quarter turn and retarded the timing another 5* (so it's at 10* now below 600 RPM's and 30* above 600 RPM). Started right up, but once that initial bit of fuel from the squirters was gone, it died, and kicked backwards again when I tried to re-start.
I have another carb I might try, but it's only a 650, so I don't know if it will be any better.