I'm no mechanic but I have to ask are there any failsafe features in the engine? If my engine doesn't have cooling water flow after so long or oil injection on 2 strokes the engine will not start. Some have alarms that sound some do not on the smaller motors like a 60. Then it's the obvious stuff, like plugs, wires, condenser, distributor, right down the check list to the Stator. It could be a bad contact at the kill switch, that took a bit of searching once. One or more than one will cause a no start scenario. I have not helped work on 4 strokes but the basics are the same. Now with the newer 4 strokes with all the electronics computerized systems even my circle of back bay mechanics are lost.
Good luck, maybe it's time to spend a few bucks and bring it into a Marine dealer if it's not the obvious usual suspects like plugs and wires. I would.