pull the plugs, if the oils not milky, they may have poured water in the carb or throttle body hydraulicly locking up the engine,
as pistons can not compress water in cylinders, once all the spark plugs are removed the engine should rotate on the starter,
once it does add a table spoon of marvel mystery oil into each plug hole and rotate the engine on the starter to lube the upper cylinder & rings.
only after clearing the cylinders of fluids should the plugs be replaced, and engine re-started, and yes it will smoke for the first 5-7 minutes untill water and oil burns off.