Warning: Work-in-Progress thing.
Many Ryobi gas-powered string trimmers develop an issue after several years of use causing them to bog down at part throttle and die at full throttle. This condition can be easily repaired by adjusting the Carburetor. Unfortunately, here in the US these units are required by law to be fitted with tamper-resistant carb mixture screws.
(Insert rant here about sending thousands of perfectly good tools to the landfill/scrapyard in the name of saving the environment.)
Special screwdrivers to fit these tamper-resistant screws are available from many sellers on eBay. This thing is my first draft alternative to purchasing these proprietary tools. It should fit a plethora of Ryobi and Homelite 2-stroke and 4-stroke engines.
V2 includes several changes based on destructive testing. I thinned the body so I don't have to sand it to make it fit. I made the pip sharper so it till work with both slot and nock style screws. I extruded the handle into the shaft to give that joint more strength, and I made the handle a bit shorter.
V3 adds a pointer arrow on the handle.
This part will be extremely weak if you have your slicer set to align all of the layer transitions. It's much stronger if they are randomly distributed or in vase mode.
I've discovered that this tool doesn't fit all of the carbs out there. I'm sorry if it doesn't fit yours, let me know and I can tweak it for you.