I highly doubt its the mix ratio, never bothered my saws even running 20:1, just needed to adjust the carb accordingly but the engines would start and run ,just not optimal until adjusted for the heavier oil mix. Your problem could lie with either spark or fuel. If you were to put a few drops of mix down the carb throat with the throttle butterfly open, then let it close and pull the engine over rapidly with the switch in the run position, it should start and run a couple of seconds if the spark module is good. If it wont start at all then I would suspect spark being a problem.
