I bought this unit in 2004 got it running and parked it in a three sided shed until this year. Decided to get it going again but having trouble getting it to fire. Cleaned up the plugs and the carb and got a new battery (6V) to turn it over rather than cranking. Gets good spark to the plugs but just won't fire. Had emptied the fuel tank when parked so added fresh gas as well. The attached picture is a push type switch that for the life of me can't remember what the purpose is. Maybe engine kill switch?? I don't have a manual for it. Even if it is a kill switch I am still getting good spark. Thanks for any suggestions to try. Leon