Engines need 3 things to start and run.
Compression. for a Blaster over 100psi
Fuel at the correct quantity.
Spark at the correct time.
What have you done to see why it is not starting, refresh our memory?
Was the old Woodruff key sheared, if so were the tapers in good condition?
Did you replace the spark plug?
Have you checked for a constant dribble of fuel when the bowl drain screw is opened?
What is the compression?