Start with basics, make sure it isn't flooded, drain tank and pull fuel line off carb, remove plug and muffler and pull over a zillion times (ignition off) until you can see there is no fuel squishing around top of piston viewed through exhaust port or being sprayed out. Stick in a dry good plug and squirt some fuel above the piston through the exhaust port and pull some more, if it doesn't fire, the spark is too weak or occurs at the wrong time or compression is too low. Squirt some oil on top of piston and let it work around piston, then try again, might improve compression enough to fire. You have confirmed that flywheel hasn't slipped on the crank so now the coil is suspect, see if the coil will fire a plug gaped to 0.050" in air, if it does, it should fire a normal gap under compression but try a plug gapped to 0.015" in the engine. Coils are always a problem, if they are suspect, there is no meaningful test that can be done on an electronic module and replacement is all you can do.