The 3 that I service do the same thing as your's. Two of them run all the time and I didn't realize how quick the plugs wear out. Then a huge backfire and it blew the carb diaphram. There was a service bulletin about the coils not being insulated good enough and you should remove them and apply silicone sealer under them.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.