Just make sure its clean.....blow air through it but never poke wire into it or anything. There should be a little gauze filter on the main jet as well so make sure thats clean as well.
Make sure there is a nice fat spark at the plug and that the cut out switch isnt on. If it was working fine before you dismantled the carb im sure it is something simple.....I reckon its the cut out switch thats the problem personally. It should feel loose in its holder. Its usually just below the snorkel where it joins the carb. Try wiggling it a bit!
