Leaf Blowers

I purchased a Husqvarna 150BT about four years ago. The starter died within 2 years. The local Husqvarna service center refused to work on it because I purchased the blower at Lowe's. Ironically, my Stihl dealer repaired it with no problem. Obviously I had to pay for the repair because it wasn't the certified repair facility.
Now, the unit is losing power and I have to feather the throttle to keep it running and it barely runs at full throttle. I cleaned the air filter and replaced the spark plug to no success. After researching, it appears that low rpm could be caused by the muffler spark arrester. I took it off and cleaned it but it was barely dirty at all. I only run ethanol free gas in all my small engines. I am assuming it is the carburetor. Do I find a Husqvarna service center that will work on a Lowe's purchased Husqvarna or do I cut my losses and go buy a Stihl? This backpack blower is useless and I have 3/4 of an acre of leaves to take care of. Any ideas/input?