Jarrod, as roebuck has just advised you, the spark arrestor is the next most likely cause, given the symptoms you have. You'll see immediately if it is blocked - just remove the fine wire screen and try again to start the brushcutter. Unless you work in dry areas or bush in summer, you needn't be in too big a rush to reinstall it.
Let us know what happens. If it still won't fire, repeat the priming test with the spark arrestor removed.
Please don't use engine start spray. It consists of ether, which is no friend to your engine.
