verify your firing order, make sure you are getting spark on all 4 cylinders, and do a compression test first before you continue to bang your head against the wall with the carbs. the carbs could still be a problem, but rule everything else out too then come back to the carbs.
jumping back to the carbs though, when you cleaned them did you use compressed air and blow through every single passage? if jetting is a problem, don't try to start it while holding the throttle open because you will be forcing the lean condition. at least with the throttle shut, you are limiting how lean the engine can be with the idle mixture screws. you may have to at most crack the throttle. in these carbs, there is a jet that is pressed into the carb under the rubber plug. this is your pilot jet and controls fuel flow to the idle mixture circuit. if this jet is clogged, it will not idle at all on that cylinder. it has a TINY orifice that can get clogged very easily. I have been able to remove them by threading a machine screw into them and pulling them out with a pair of pliers. this will create threads in them, but will not affect the way it runs because its not damaging that orifice. afterwards, it can be tapped back in with a punch.
