Echo srm 2500 no start

Hello, and thank you for reading this. I am new to this forum, so please excuse me for any forum faux paus. Anyway, I recently purchased an older 2500 string trimmer, which was running fine but had a leaky primer bulb. Replaced the bulb and everything was fine. Today, it started and ran a few seconds and cut off. Since then I can't even get it to try to start. Tried a new plug, the spark appears ok, I wouldn't say it is blue, but it is yellowish and consistent, and kicks hard when i hold a screwdriver in my hand, stuck in the plug wire, and spin it over. Even with a new plug, it does not even try to start with starting fluid or putting a little gas in the carb throat. The compression seams fine ( I can't hold back the compression by putting my finger over the plug hole, and it pulls with the same compression as it did when it was running fine). Lastly, while pulling it I can feel that plenty of air is coming out of the muffler. The only thing I can think of is something in the coil, maybe the spark Is too weak to jump the gap with compression on the plug, or somehow the timing is off. The funny thing is the last echo string trimmer I had, given to me not running, had the exact same symptoms, and I eventually threw it out, as my best guess was a coil and they are $100.00. Anybody run into anything like this before? Really don't want to drop a boat load of cash on parts. Thanks...