Hi Clarke,
My GT245 runs rough and smokes at all throttle settings, and back fires too.

You believe that replacing both coils would be the answer?
I have been told to consider replacing the carb.?

Your answers would be appreciated.

Hi,
On the Kawasaki engine the ignition or the carb can cause this. The engine is also particularly sensitive to a dirty air filter. I would try cleaning the carb first. There are two different ignitions possible, one is a two piece arrangement and the other is a single piece. Most of the time you can replace either with the one piece unit.
Peace,
Clarke