What can be the problem beside my weed wacker? I have a ryobi 790R weed wacker that starts but dose...

I have a ryobi 790R weed wacker that starts but dose not stay on.I can turn it on in a minute and it will start but when i let travel of the trigger it will shut off. What can be the problem near it?
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Answers:    empty adjectives fuel put fresh in,brand name sure the choke is not stuck, adjust the idle screw, or you might meed a carb tackle installed... I have never have one that I didn't have to something on.
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Try adjust the idle speed. It will be a screw next to a spring on it. You can see it move when you pull the trigger. Once it will run lacking holding the trigger adjust the fuel/air mixture. There should be two screws on the carburetor. They will merely turn about 1/4 turn. Turn them untill it runs smooth. If this doesn't work you will most predictable have to modernize the carburetor. It is not a hard errand, and you can get the apparatus from most any small engine shop. Also check the fuel filter, it is in the fuel cistern on the end of one of the two lines. Clean or replace it. Use a piece of rope with a hook bent on the expiration to fish the fuel line out of the reservoir.
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