Outdoor Power Equipment and Small Engines - Help!homelite string trimmerut20026

ENGINE STARTS BUT WILL ONLY RUN IN HALF CHOKE POSITION AND I NEED TO GUN IT TO KEEP IT RUNNING,THE MANUAL SAYS CARB NEEDS ADJ.,I DON'T HAVE TYPE OF TOOL NEEDED TO ADJ,SAYS TO CONTACT DEALER,THERE ARE 2 ADJ.SCREW HEADS AT CARB BUT NOT ACCESSABLE TO ME.IF I'M ABLE TO GET TO THEM,NEEDLE NOSE ETC.,WHAT FUNCTION DO THESE SCREW ADJ. PERFORM ?i.e. IDLE OR AIR FUEL MIX ???ANY INFO WOULD BE GREATLY APPRECIATED:confused

The idle has a fuel/air mix as does the entire rpm range in an engine. There are different setups for different reasons. Some of the adjustments are blocked off for emission control purposes.

If there are two adjustment screws, that are the metering type, one would be the low rpm and the other would be the high rpm screw. The latter would also serve to meter the loaded rpm of the engine.

The low rpm adjustment will affect the idle of the engine and will also affect how the engine accelerates in the the high rpm range.

In addition there would normally be a way to set the idle rpm which isn't a mixture adjustment, but usually a throttle opening screw.

I would remove the muffler and try to run it without before I adjusted the carb. If it runs fine with the muffler off then you need to clean the muffler and spark arrestor before you replace them. They get plugged somewhat with the oil mixture and cause just the problem you are having.
There is a You Tube video that shows how to do it but I don't remember what you put in to search for it.