That could be the fuel filter.

I'd start with cheapest and easiest. If the machine has been sitting for awhile, the fuel lines may have become "soft" and are closing under pressure, cutting off gas supply. Replace.
Next step would be to rebuild and clean the carb.
This is what it took to get my GT-2000 running. Been running fine since.

Stop by your local Echo store and pick up the fuel line kit, fuel filter and carb kit and install all.

Three fuel lines into the tank. One has the fuel filter on the end in the tank. On barely gos into tank and is fuel return line from carb purge. Third line also barely goes into tank, has a plastic beather on the end outside of the tank and allows air to enter tank as fuel is used.

Carbs and fuel line need replacing every couple of years, Echo even says to go through the carb every year to maintain proper running and is required maintenance under warranty.

Once in a while one of the crank seals will come out. This destroys primary compression which is in the crankcase and in effect is the required supercharger effect in any 2 stroke which charges the combustion chamber.

Last, or actually first, none of the above should be done without first verifying the compression and combustion chamber are in good condition. Look for a minimimum 110 psi on a compression guage as well as inspection cylinder wall and piston by removing the muffler and looking into the exhaust port with piston at different positions. 110 is the lowest I allow for an Echo, good will be more in line with 125 to 140.

The smaller the compression gauge and hose the better when checking small 2 strokes. In any case, crank until the gauge no longer climbs. Displacement is tiny and it takes more then 3 pulls to pump up a gauge, especially if using a large automotive type.

I disagree with replacing carb and lines every year,even every other year..............unless the machine is sitting with old gas,there absolutely no reason to replace carbs or lines.....................unless an idiot was using dirty fuel,(especially if there was water introduced to the fuel supply) then that's 1 thing ..........................the only thing I can see about replacing carb parts is,the machines run so lean that,if the carb leans any more,the machines will seize up or blow a piston........................seems kindof funny that a crank seal will come out also....................not pickin' just the way I see it

Can be very costly to replace all this every year. I all Echo commersial grade equipment and only change plugs,air filter and gas filters. When a machine runs bad than I take a part the carb. I have all my stuff for 15 years now and took only two carbs apart. I have a Back pack Blower, Weed Wacker, Hedge trimmer all Echo. Great product

Sorry, didn't mean to say replace carb every year, rebuild it is what Echo advises to maintain emissions.

If the machine will not start after spraying starter fluid in the intake, then check the on/off switch .......many times the switch will go bad , if it was a fuel issue it should fire up and die when starting fluid is introduced in the intake port........Ben

I would also check the little stupid spark arrester screen in the muffler! It gets clogged and won't let enough Pressure out to help create a vacuum fir fuel flow. I always remove those screens as. Soon as I buy something. They cause so many Problems and people always over look them