Honda Sky Idles too fast then cuts out and wont start?

My son has just got a Honda Sky. It had been stored in a garage for approximately 1 year before he got it. The first time he rode it, he got about 3 or 4 miles down the road and it cut out. When he eventually did manage to start it again, it was running too fast. It then cut out again completely and now wont start at all. Any ideas please?