The fuel leak from the carb stopped - no idea why.
Wilbuild
It is not impossible to have a spec of dirt hold the valve open. With the bouncing around they take from cutting lawns it might've been rinsed through the engine and now the valve seats tight, but if the needle valve looks like this
it will never seat tight and leak making the engine run rich, smoke, run at lower rpm then it should, go through more fuel, fowl spark plugs.
Replace it if worn.