Assistance w/ dredded Homelite trimmer - Tool Shed Forum - GardenWeb

As far as carburetor adjustments...

There will either be 2 or 3 screws to adjust on the carburetor. With two adjustments, you would most likely control the low-speed mixture and idle speed. If you have a third adjustment screw, that would most likely be for high-speed mixture.

A good rule of thumb on the mixture screws is to turn them clockwise until they do not want to turn anymore. This will seat them against the carb body. Don't seat them too tightly against the carb body, or you could damage it. Just turn until you can tell they are seated, but don't try to force them any further. Then back each adjustment screw out 1 full turn. This should be good enough to at least get it running.

Once it is running, warm it a couple minutes, then adjust the idle speed screw to set a reasonable idle speed. (The idle speed screw usually just is a tapered end screw which will manually hold the throttle butterfly open a small amount.) Next, adjust the low-speed mixture screw (use maybe 1/8 of a turn until you see the results) until you are getting the maximum rpm at idle. Then, bring it to wide-open throttle and adjust the high-speed screw to give the maximum rpm at WOT. This procedure has worked pretty well for me on small engine carbs.

If there are plastic limiter caps on the end of the mixture screws, these may need to be removed for accurate adjustment. As an example of this, I have a set of Homelite hedge trimmers that used to run poorly, and it seemed no amount of adjustments would help. I didn't realize at first that although I was turning the plastic limiter caps, it was not moving the actual adjustment screws (the plastic caps turned without moving the mixture screw). After removing those caps, I was able to get it running well after adjustment.