I had this happen recently on a 2150. Even though the fuel lines looked good, supple, etc. I just put in all new 3 fuel lines. problem solved.
worked for me, you might another problem.
thanks,

Thanks for the info. The first thing I did was replace all the fuel lines as one cracked when I removed the carb. I just ordered a new carb for it last night. Hope that does it.

probably a diaphram/needle and seat problem, not pumping fuel or seat sticking and not letting any fuel through to the comb chamber. New carb. should fix it. go to warblo or zama.com (probably a zama carb. if it a new saw?) they have excellent troubleshoot guidelines along with rebuild procedures. It does fire after it shuts down and it will run off carb cleaner (by a short blast down the carb venturi after it quits right? this procedure will bypass the carb. and verify the ingition system/switch is working properly.

Yes, if I pump the primer really hard it will start right back up, run a couple seconds and stop. If I don't pump the primer it won't restart. Sure sounds like a float issue but I cleaned the dang thing 3 times and checked the float and stuff. Oh well, I'm sure the new carb will fix it. I haven't had a lot of success with kits on these Walbro carbs. I have just started replacing them if the equipment is worth it.

It will run on starter fluid...