Hi ternandes,

If the trimmer had been running well and then started having issues it is unlikely that the problem can be solved with an adjustment. The problem is likely due to dirt or other debris in the carb. You can replace the carb or try cleaning it. A new carb will come set from the factory to operate at sea level. Minor adjustments may be needed to tune it for your location. It is best to have a shop tune the carb as you can damage the engine if you are not sure how to make the adjustments. The shop will also have the special tools needed to make the adjustments.

If you want to try cleaning the carb we have an article and video that you might find helpful. You can view it here..

How to Clean a 2-Cycle Carburetor.

I hope this helps,

-UtahAV
-Mark

Make sure the throttle cable is OK

If the unit has been used regularly, it may be a exhaust port blockage of carbon. Remove the muffler, and look inside the hole, If you see lots of puffy, black stuff- simply scrape it out with something that won't scratch the port opening...Like a pop-sicle stick or wooden pencil.. If there is carbon build up you may want to clean your muffler also.. But make sure if you clean the muffler with something flammable (which that's ok).. just be sure to rinse it well and let the muffler dry.."NO FLAMES" !! Hope this help with rev up situation..