I have a tao tao 150cc roman scooter. I just bought it and uncrated it. I seem to be having some trouble... It was a struggle to get it to turn on. but once it did, it would stay on with a very high idle. Once adjusted it would die. As well as if it wasn't adjusted and I ran on a high idle, when I would stop it (press the breaks) the scooter would die. I have changed the carb. what could be causing this?