I bought an Stihl 028 at an estate sale yesterday. Brought it home and drained out the old gas, which did not smell that bad, and put in some ethanol free, a quick squirt of ether and it fired right up. Idled OK but not great and I screwed the L screw in all the way without any effect. So i assume a carb cleaning and rebuild is in order. Some questions: Was there more than one carb on these over time? If so, will the serial # tell me which carb i have or do i need to remove it to identify it? I've been happy with the parts I've gotten from HLS but they only list aftermarket carb kits. Are these reliable or should I try to find an authentic kit? Is there another vendor that anyone recommends? Should I replace the fuel and impulse lines while I am at it, and same question about aftermarket parts. Thanks Larry