I have a Poulan PP4218A Pro.The problem I have when I try to throttle up the engine it wont throttle all the way up and the trigger does not release properly.

Videos here

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Take it backl and get it replaced.

Check to see if the throttle lock is stuck on. If it is quickly squeeze then release the trigger to take the lock off. If the trigger will not spring back you have other problems with the linkage.

The precision bent throttle connecting rod can only go in one way CORRECTLY.... if it has to be forced or bent, stop and figure out the puzzle before any damage is done.

I'd suggest placing the carb temporarily on the mounting studs on the side of the cylinder. Don't install the filter and nuts etc yet. Take the throttle rod and lay it in place this way and that way until it looks like it matches the trigger end AND the carb end. Usually the carb end has to be installed on the carb while it is removed from the engine as tightness of space won't allow moving it all over to poke it in the hole. Once it is on the carb and you are sure of the orientation, slide the carb once again over the studs and lay the throttle rod by the trigger.

You need about three hands to hold the trigger, trigger lock, trigger return spring and the handle together while you figure out how to snap in the top of the handle and start a screw under the handle.

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!

5/32 inch diameter round file

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!

hey pete
This is easy, prime bulb 5 to 7 times with choke lever full out. Pull string, once engine starts turn off choke and pull string again. ( throughout process do not pull trigger )Engine should start, let it idle 30 seconds, then finally pull trigger to rev up engine.