Certain the spark is getting to the plugs? You might want to pull a spark plug, or just wire, and make sure a nice blue spark is getting to the plug. Ground the plug while wire is hooked up to it. Crank it over and see that there is spark at the plug.
Does it back fire or make any grunting noises while cranking after putting some gas down the carb? Or just crank?
If it still has the stomp starter, make sure the wire from the small terminal on the starter goes to the + side of the coil. It bypasses the ballast resistor in the ignition circuit to give the coil battery voltage.
