Thanks Karla. The saw is about 2008. The fuel filter looks pristine white, and the problem came on very suddenly. That said, I do have a filter ordered just in case. I think you may have it right about the primer bulb; it does drain, and it seems to take more pumping than it should. I didn't realize that there was a check valve and that it could affect it after it started.. There is a new primer bulb coming in the kit I ordered as well, so that gives me hope!
Thanks,
Nate