Are you using a known good spark plug ?
Take the spark plug cap off and check it with an ohm meter.
There is a resistor in the one that came from the factory,and the resistor can go bad.
If all of that is good,remove the blue-black wire from the terminal block;[magneto side] and connect the exposed
end with the green-black wire in the terminal block
If no spark still, remove the black wires from the terminal block
If still know spark file breaker points with disposable finger nail file and set the breakers to .017
Replace high tension coil and spark plug wire with known good one,as a last resort.