Just had the same problem last week. First take off air filter and look for signs of moisture. How dirty is the air filter? Is it new or do you need a new one? How dirty is the fuel filter? Next, check the carb. for water. To do this take off the little bowl on the bottom (bolt holds it in place). Wipe out the bowl and put it aside. You now need a small wire (just smaller in diameter than a paper clip) and clean out the gas line in bottom of carb., but be careful not to push any dirt/debris further up into carberator. Put it back together and see how it runs.