A lot of people overlook the tank vent on saws. I have had tank vents so clogged that they create tons of pressure, and if not fixed, it can blow a small hole in the diaphragm and make a saw do crazy things until it's figured out. You can tell a clogged tank vent by running the saw a while, and shut it off, turn it on its side, and twist the fuel cap open and listen. If it "relieved" itself, it's got a clogged vent. Sometimes it will do that if sitting for a while closed up. Pressure is pressure.....
Also, if a vent is missing it's little plug in it and leaks, it can lose some pressure and cause a saw to start really hard. Long story short, I guess I am just saying like the member who said to check the plastic rings on the boot, which is great advice, is to give that tank vent a check too.
I discovered my 200t's had crappy vents from the factory, and they sold a vent repair kit which came with a punch to drive the old one out, and replace with a nipple, small line and filter type thing. Those worked 100 times better than any factory vent. I have 17 200t's and almost all of them got that tank vent upgrade when I do a top end.
Other than the tank vent, it could be a plugged screen in the carb. It doesn't take much to clog that little screen.