I have a Craftsman gas trimmer and a blower. They both have 2-cycle engines. I need to adjust the carb on the trimmer but the screws require a special tool. The heads are round with ridges or knurls around the outside. I checked the stuff I got with the trimmer, no tool. I looked in the manual, no tool mentioned. I wandered over to my Sears store, never heard of it. Called the Sears service line, spoke to three departments, none have a clue. Seriously? Its not like this is some off-brand, they must sell thousands of these engines every year, all around the country. Surely I'm missing something here (along with Sears). What do I use to adjust the hi and lo on a Sears-mounted 2-stroke carb?