Re: Back fire when cold? Edelbrock carb
X3 on the timing question. Idle numbers. Dave Ray and 4 Speed are thinking you have the timing too retarded at idle. Thus, the "36 degrees doesn't tell us" comment. Retarded timing, sooty plugs, rich idle.
I'm in Houston with an Eddy on an AirGap disaster. Like any disaster, it's cool to look at. No heat spacer, but it would hot start better if I had one. With the mechanical choke adjustment dialed in per the book, mine has started great, comes onto the highest high idle step and warms up fine for the first minute or two. Then when it drops down to second idle step it would die unless I was vigilant and on the pedal. And it was REALLY hard to start because it was lean. Never backfire. Always problem below about 60 degrees. Restart it and let it warm up to a coolant temp of about 160 (vs your 180) and then I could drive it even though the choke wasn't fully open. This is about a 6 minute window, versus your 10 minutes.
I just gave it 3 ticks on the choke dial richer last weekend. Temps were in the 50's so I could play with it. Cold start up high idle was the same, dropping to the second high idle step was better because the choke dial was holding the choke on more. No dying now. More drivable before fully warmed up.
FYI I'm airflow limited on my cooling system and running a 180 stat, so in cool temps I'm never above 180.
90 Corvette ZR1
TC# 3094 ACES# 7297