Bought this new, 3,500 miles on it now. Quit running 3 or 4 years ago. I took the side cover off and checked the coil that is used to fire the plug- or at least send a signal to the CDI to tell it when to fire. Open circuit so I replaced it. Ran good so I hooked my mower to it. Ran good for about an hour and quit again. This time the coil ( the one inside the stator) checked good. No fire. Have tried another CDI box with no luck but I had no history on the box I tried. These guys are EXPENSIVE! Any new ideas?