The intake will suck and blow as its a piston port motor.
Does fuel run freely out the fuel line??
Is the main jet blocked? Is the main jet passage into the carb blocked??
Needle and float in the carb OK and matched?? Fuel height in the chamber is important.
If the crankcases are dry i usually dribble a bit of 2 stroke oil in there.
You could try a teaspoon of fuel in the plug hole, if it wants to go then you know that you have an issue with fuel supply.
If it has bad compression and bad crank seals it might not want to run.
Good spark outside the motor does not mean good spark in the cylinder at about 7 times atmospheric pressure.
