2 things...Bob Wright probably has forgotten more than the rest of us know about echo saws, listen to what he says he's a good sopurce of info. Second, IMHO, make sure you have spark before you do anything to the fuel system. Get a spark tester that works for mechanical or electronic ignition and set the spark gap as appropriate...IDK what that would be...but somebody here should...and ground out the ground to any good metallic ground, crank the engine over you should have a strong blue flame, if you don't it's the ignition system. If you do, it can only be low compression or fuel system related.