I think that's it. Call them & see if they will do a core swap or something of that nature. That sure does sound familiar, I remember that when I found out about the place I was pissed @ myself for not checking into that. Those older Cat stators used to go out at about 5000+ miles I believe. That drove me crazy, it would fire up fine ( cold ) then as soon as I got to the farmers field it would back fire,missfire, fire on one then another ect... I dragged it out of the field 3 times and pulled the carbs 3 times before I figured that 1 out.