My chainsaw will run only full throttle and when you let of of the trigger it wont idle it will die

Check your throttle cable as it may corroded and has the carburetor held in full throttle position or someone has the idle speed screw turn all the way in.

adjust the air fuel intake i always go all the way in with the screws then 3 full turns out and the half turn adjustment after that hope that helps you out

Fuel starvation, start by replacing the fuel filter in the tank, check the fuel hoses for leaks up to the carb.

Open the carburetor area cover and remove the air cleaner so that you can observe the throttle arm and the idle speed screw which stops throttle movement to set idle speed. If the throttle arm doesn't come back completely to the screw, then likely, the throttle trigger is jammed with sawdust/dirt that prevents the throttle arm from returning. Disassemble the trigger assembly making notes of part placement as you go. You will usually find a plug of sawdust in the trigger mechanism. Recheck the throttle arm motion after putting the trigger back together. You may have to advance the idle speed screw several turns CW to be able to keep the engine running when the throttle works correctly. Idle speed should be set so that the engine continues to run, but the chain doesn't try to turn. Hope this helps!

Operate the throttle trigger to see if it returns to the idle speed screw when the trigger is released. If it seems to 'float' somewhat, the trigger assembly may be full of dirt/sawdust, or the throttle return spring on the carburetor is damaged or disconnected. When taking the trigger assembly apart, be sure to make notes so that it can be put back together correctly. Make sure the throttle plate in the bore is tight to the shaft. When the carburetor was off of the engine, did the gaskets and heat insulator seem to be ok? Any air leak behind the carburetor will cause run-away speed. As for the engine quitting, check the fuel filter, air cleaner, and muffler for plugging. Check the condition of all of the fuel lines for decay or other damage. Did you check the condition of the diaphragm in the lower chamber of the carburetor--it should be quite flexible with no holes or cracks. With the jetting set where you have it, the engine should be 4-stroking heavily. Hope this helps!

Expose the carburetor so that you can observe the action of the throttle lever on the carburetor. The trigger should move the lever from the idle adjust screw to full throttle stop. If no movement observed, remove the trigger assembly from the front handle (make notes as you remove the pieces) and clean the area of sawdust/dirt accumulation. Recheck the action after everything is re-assembled before starting the engine. If the idle speed is still excessive, then turn the idle speed screw several turns CCW until the chain stops turning. Try wiggling the carburetor body to see if it has come loose from the engine. Hope some of this helps!

Carb needs teardown and cleaning. May be a stuck float or clogged jet.
Spraycleaner just wont cut it.

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Open the cover over the air cleaner so that you can observe the action of the throttle cable and carburetor lever. Operate the throttle--normal action is lever wide open at full throttle and lever resting on idle stop screw when throttle released. If action is restricted, disassemble the handle where the throttle trigger is located and clean out the sawdust. Recheck throttle action. The throttle cable shouldn't require lubrication. Clean the air filter and check the operation of the engine. Hope this helps!

Remove the air cleaner assembly so that you can see the action of the throttle mechanism. If nothing around the carburetor throttle arm is broken or out of place (the return spring), then remove the screws in the throttle trigger part of the handle and look for sawdust blocking throttle trigger action. Hope this helps!

This does take a little time to get it just right. Start at one full turn for the h and l. Work on the high first and after you get the H running work on the Low. They have to work together. So if you get it to idle and run at full throttle but it hesitates when you pull the trigger just adjust the low a little higher.