My 1995 250 timberwolve is going thru plugs continuosly. It does not use any oil and when I go to replace the plug, it looks normal.Ocassionally, It has a tendency not to idle properly. It idles fine then goes higher (rpm). The carburetor runs good. It does not hesitate or stall. I replaced the plug at Thanksgiving and relacing it again. It does not have1 hour on the plug. The fuel is fresh in the tank. Am I having a electrical surge that takes out the plug? I need some advice please