I've got a 1970 Mustang
with a Pertronix Electronic ignition and high energy coil. Also have a 600CFM edelbrock carb that hasn't been cleaned out in about 2 years. Every so often when I go to start the car, it won't fire for about 50 seconds. Then it either fires right up no problem or shoots out a huge could of grey smoke that smells like semi-burnt fuel (and cackles like a stock car, which I don't really mind). It used to happen about once a month, but it happened 3 times today out of about 6 times of starting it. It doesn't seem to matter if the car is warm or hot. I tried to start it cold and it just cranked for about 50 second and then I drove to the bank and it happened again when I tried to leave.
I was thinking that the carb is just getting gummed up, as it did sit for a couple months without being driven a year and a half ago (when it started), but the thing that confuses me is that it takes almost exactly 50 seconds of cranking every time with no variation ever. That makes me think it's some kind of electrical problem?
What does the internet think?
Thanks for the help!