I have a weibang ip70 model it is very hard to start. So i brought it back tothe dealer and he said there was nothing wrong with it. He started it using easy start. And he blamed dirty petrol. I have had briggs an stratton engines most of my life and they always started no problem. Even when it does start it is spluttering and missing and i have to use the choke all the time. Surely this is not normal. Hope you can give me some advice. By the way it is only four years old.