2007 trx250 problem

Looking for some help. I bought this quad brand new last year. After about the 5th time is was ridden, it would not start. It would sputter for a second, but would not stay running. I took the carb apart, cleaned it and put it back together. Nothing changed. If I spray starting fluid inside of it, it will run ,but will not stay running. I am at a loss, this thing only has about 7-8 hours on it.