Your engine will run hotter than 'normal' for the first 1/2 to 3/4 of a gallon of fuel. If it runs hot, give it more fuel....If it still runs hot, give it more fuel. If nothing you do seems to help, then I would look at getting a replacement engine.(warranty)
If it isn't a tuning issue, then it could be defective. I would instist on a new engine, not just a carb, if that is what they say is wrong. If the carb is bad, then your engine is bad, now, from breaking it in with a bad carb.