Try taking off the carburetor bowl and clean it out. I use a 1/2" box end wrench, although a small socket might work if you have enough room under it. Drain all the gas out and check where the fuel line goes into the carb. Spray it out in there, see if any dirt, rust, etc. comes out. Watch your eyes! That carb cleaner is rough on the eyes!! Squirt carb cleaner up in and around where the bowl fits on the carb, work the float and needle by hand while squirting it as well. Squirt up in the center part where the bolt holds the bowl on. Probably fuel starvation issue. Those throttle and governor linkages work as follows: The throttle SPRING pulls the engine INTO FUEL. The GOVERNOR (solid link) pulls the engine OUT OF FUEL. The balance point is the RPM.