If it's running fine ok otherwise then I woulden't say so, if you have the correct mixture and spark and it's still not right I would say that cylinder has lack of compression, or are you sure coolant is not entering that cylinder?
i.e. blown HG or cracked head, hopefully it will be one of the former and so simple to sort.
Martin
Last edited by martysmartie; 08-11-2011 at 07:15 PM.