A few things I have learnt the hard way. Pull your glow plug out and heat it up it should glow red almost instantly, if you were running really rich turn your truck on it's side where the pipe is make sure your doing it some where that you can spill oil, I ran too rich and my monsoon wouldn't start I emptied the oil out and she fired right up, And are you priming through the carb?
Edit when you were breaking it in did you leave it at bdc when it was cooling off thats very important. And if you left it that long did you use after run also very important. Don`t blame the truck if you didn`t do either of these things.