Hi, thank you for all your replies. It is a 2003 model with a GCV530 OHC engine. It runs on both cylinders when idling and sounds ok, but as soon as it revs up and warms up it plays up. I have checked the carb and the choke is shutting off correctly and starts the engine easily when cold. The previous owner stated it was working perfectly, but it cut out and this problem started when driving it into the garage for the first time after delivery. Unless I have been mis-sold a faulty machine, something may have happened during transportation, which leads me to think it's an electrical issue? mistermowerman - Should I replace the ignition coils or something more? thank you again for your help