I just got done putting in a new gas tank, oil and filter change and went to turn over the engine. It chugged once or twice like it was going to start but now the engine is turning over but won't ignite. I can see fuel flowing from the tank thru my fuel filter. I put an external spark tester on one of the spark plug wires (they don't penetrate the wire, just lay on top like this http://www.mechanicstoolswarehouse.com/ ... m=LIS19380 and it is not showing spark but I am not sure if this is accurate because it looks like I have the original ignition system and I believe it is shielded. In summary, I have fuel, I have air but no bang bang.
Question:
Can someone suggest an ordered list of what I should be checking? Or, is the issue obvious to you and there is a specific repair I need to make?
I have attached a picture of the ignition system in case that is pertinent.

Thank you in advance for any insights/help.