For years I've battled the carburetor idle circuit blockage, I'd say once or twice a year. If the carb was noticeably staring to misbehave, I'd run a bottle of fuel system cleaner and lo and behold, made the situation worse. Had the tank boiled and sealed, fuel lines replaced, but the problem persisted. The last item I could think of was the metal fuel tank filler tube. Look what I found!
