Definitely take it back and don't accept that they will work on it. My dad had a Stihl that I got from him in the 90's. It was perhaps 10 years old and lightly used when I got it. It acted the same way. I had it to 2 different Stihl dealers several times and they couldn't fix it. I was told to take it to this Amish man about 30 miles away and if he couldn't fix I might as well throw it away. He had it a couple of weeks and then notified me that it was ready. When I went to pick it up, I noticed a stack of logs out back. Told him to come with me and I will see if it is fixed. It started right up and I started to work the crap out of it. After 10 minutes, I set it on a stump and told him, "We'll go in and make out the paperwork and if it was still running or we could start it is fixed". We came out and it was not idling. I handed the saw to him and he pulled his ars off trying to start it. Not fixed. He took it back in and I returned a week later. He grab the saw and we went back out to the log pile. This time he worked it over. Turned it off several times and it started with the first pull. The saw ran for 2 years good and then went back to the original problem. I have had Huskies and Poulans every since until last summer when I bought my MS250. It has been a great saw and I hope it continues to run great. All I can say about my first Stihl is it was a great tailgate saw. Saw hard until it got good and hot then drop the tailgate and commune with nature. If my memory serves me correctly, he finally split the case and resealed it. If that makes any sense to you experts.
Woodwidow was not there. The inspectors were there but didn't want to stay outside because the bugs were pretty bad.