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Engine needs Fuel in the right quantity, Spark at the right time, and Compression, to run.
So. Do a Compression Test. Check to see if all Cylinder have a Spark that can jump a 3/8" gap, and then the fuel system. Could be dirty/gummed up carb(s). How was the engine winterized? Check fuel flow from pump, and Pressure
There is a slight chance that the Linkages to the carbs are unhooked
