please help...if it's not one thing it's another....

so we replaced the heater core on my car yesterday, tried to start it that night and it gave us a little trouble but when we finally got it going it ran great and heater worked great (very nice and hot, like new)

...but now today I go out to start it and it refuses....it cranks but never starts...thought maybe my choke was sticking or something so we tried opening it by hand several different ways (slightly...all the way...you know, see if it's the chokes fault) still won't start and after a little bit of messing with it like this then some air or fuel or something shoots out of the carb. everytime we quit cranking it. (i'm assuming fuel, you could see it and even feel it when in the car, like a loud puff)

So could there have been anything inside of the car, under the dash, that we might have pinched or unhooked or something that could cause this? just trying to figure out where to start looking for the problem....I swear...I can't afford another big fix, might have to part ways :(