Hi all. New member from the UK so please be gentle. I've got a Victa Mulchmaster 550 2 stroke mower. Fantastic machine. However it currently won't start. Spark was weak so changed spark plug, still weak so put a new coil on (luckily I have a spares machine). now strong spark. Stripped down the carb, seems fine and plug getting wet. Checked exhaust, fine. Cylinder head gasket fine. Changed rubber o ring underneath the starter recoil. Even changed the fuel, getting desperate. Any ideas would be very much appreciated. Stu.