Strange, I've got a 2003 srm-260s with at least 3 years full-time use to it, and I don't recall ever replacing the carburetor. I also find it odd, that story of the "new" carbs was going on back then as well... Makes me wonder just how long this supposedly "new" design has been around? But no, to my understanding they can not be adjusted, however this is rarely the problem even on carbs that can be... Just strange they'd have to replace the carb, twice. I suspect a faulty coil, which is the LAST thing the dealer wants to replace as to my understanding they carry a lifetime warranty. Oh, one more thing: DEMAND your old parts! Anytime a dealer replaces something, before (or at the time of) dropping your equipment off, make SURE to tell them, YOU want your old PARTS! Otherwise they'll tell you they threw it in the garbage, gone... They're not supposed to, anytime a customer requests old parts they should still have them, but what can you do? How do I know... My trimmer sat for 2-3 years not running right, all the while getting dumb looks at the dealership, in the end it was the coil and I went through a bit of trouble to get them to fix it! Yeah, now that's on top of it being me who had to figure it out, that trimmer sat in their shop for months on end. Not saying that's necessarily the problem here, but it could be. To my understanding when it does that it's usually the coil!