All good advise on the preoiling its a must do,I would also crank the eng around with the plugs out after the preoiling & also ck.for spark @ this time,disconnect the fuel line to the pump so you don't suck up any crap {if it works},prefill the fuel bowl through the top carb vent & pump the carb see if the accel.pump works {I use a hair dye bottle & top to prefill & spray fuel into carbs & keep engines running if need be its one tool I use almost every day},see if it will run before spending money rebuilding carb or anything else.