Moped not starting carb problems?

Heyy i have a sukida sk50 qt21 sportsman...ive left it in the garden sitting for some time..the bike does now not start,we've tried everything lol.Got brand new battery,The petrol is coming from the Take going to the carb but just staying there.Starter motor works,tried easy start,checked jets,checked,float,checked valve springy thing,checked diaphragm.The bike just wont start :( please please help.need it working.My dad says its definitely a fuel problem...something not quite right with the carb.We checked float and little pin thing that pushes float up,bought another one justin casee it was that,changed main jet,but it stilldon'tt' work....what else could it possibly be..i bought a second hand carb to take bits of it...but even swapping and changing bits still wont start it....bike sound like its trying to start but just doesn't fire up.Dad said petrol going into carb but float is staying closed i think or stuck up.n filling up...some one said check main jet ,we did ,can blow through it and it looks fine.Diaphram aint split either, I just don't know what it could be,dads tried for days and days,he said it could be just something simple with the carb...pleeeeaaassee help asap.