take the spark plug out and try the following:
first:
Do you have a spark?: take spark plug out and put the lead back on and holding carefully with a pair of insulated plyers against a metal part of the mower pull the starter cored and see if you get a spark. for each pull you should see 6 or 7 sparks.
second:
Do you have compression? with the spark plug still out pull the starter cord with your finger over the spark plug hole and see if you have pressure.
if you have spark and compression there must be a problem with fuel delivery, probably a blocked fuel jet in the carb. remove the carb and clean carefully.
Paul, August 2009