An Echo chain saw that starts but won't keep running may have a simple problem you can easily correct yourself. Start by reviewing the correct starting procedures in your owner's manual. Then, if some basic troubleshooting checks don't solve the problem, you may have to visit a professional Echo repairman.
Review your Echo chain saw owner's manual for proper starting procedure. Check to ensure your Echo chain saw is filled with properly mixed and fresh fuel. Gasoline left in a saw for a long time will deteriorate and cause it to fire improperly. Next, check that the chain brake bar is not locked and the chain will run freely; also check to ensure the chain is not binding in the bar and that chain oil remains in the reservoir.
Check your Echo chain saw filters. Start with the air filter, on top of the saw. Remove the cover, and check whether the filter is dirty; if so, either clean it by blowing out dirt or replace it. While the cover is off, check the cylinder fins to ensure sure they have not become blocked. Check the fuel filter, which sits inside the gas tank. Pull it out with a piece of wire through the fuel inlet. If the strainer is dirty, replace it. If the tank itself seems dirty, drain it, flush it with fresh gasoline and then refill it with a proper mixture.
Remove the spark plug to ensure it remains clean and has the proper gap (your owner's manual will inform you of this measurement). If it has become fouled, clean it or install a new spark plug. Check and clean the exhaust port and spark arrester screen.
Adjust the carburetor on your Echo chain saw. On the left side, near the starter rope, are an idle adjustment screw and two needle valve settings, marked "H" (for "high") and "L" (for "low"). Turn the "H" needle counterclockwise to stop. Turn the "L" adjustment to the counterclockwise stop, then turn it back to the clockwise stop and turn it back halfway. Start the engine, and turn the idle adjustment screw clockwise until the chain begins to turn. Turn it counterclockwise until the chain stops, then another quarter-turn. Run the engine at full throttle for a few seconds, then check whether it returns to normal idle. If not, turn the "L" needle counterclockwise one-eighth turn.