I see eBay had new oem carbs for 81$ so between the aftermarket Amazon carb then kit then other oem parts I’m sure a new carb could have just been swapped and been pretty much guaranteed to solve the issue if it is because of the carb. If not then the carb would have been ruled out, rebuilds don’t always work as intended and I don’t care for knock off carbs in general because they seem very hit or miss. Generally the 450 is a very durable blower but obviously they can have issues also like anything.