Remove the pilot jet. Spray carb cleaner up into the passage for about 30 seconds. Then blow compressed air up into the same passage (this part is very important). Replace pilot jet. Do the same for the mixture screw. Be careful not to lose the spring, o-ring, and washer. I bet is starts fine after this. If you don't have an air compressor, take it to a shop. They will fix it for less than 70 bucks. Sadly, they will probably spend five minutes simply doing the above.