Time to go back to the basics and take another look at everything. I know you have said you have done everything I am going to say, but I am not there and can't hear or see your unit. I will accept that you have good spark, so we will go the compression next. Remove the plug and place your thumb over the spark plug hole. Have an assistant slowly pull the starter rope, you should feel both suction and good pressure while they do this. Be sure to have the plug wire out of the way or you will verify spark again if it is too close to your hand. If you feel suction on the intake stroke and you can't keep you thumb over the hole on compression stroke, you should be good to go. Next is fuel, start by removing both the air filter cover and base, we want them out of the way. Place the palm of your hand over the carb opening and again have an assistant try starting the unit after two attempts, remove your hand and you should find fuel on your palm. If no fuel, you have a problem in the carb. If you have fuel on your hand then remove the plug and see if it is wet. If it is dry, you have a problem between the carb and the cylinder. Let us know what you find.
