This might sound to simple but I was having the same problem and some one told me to clean the air filter and it worked started right up. Like I said this may sound simple and yours my have a more serious problem but try this then look for other answers if it doesn't work.
Ves Heill!
jammer
September 2008
Might be bad gas try new gas in it. It may have gained some condensation after sitting the winter. Also remove the spark plug and clean it real good( or just replace it if its been awhile)
These are the basics to try first.
Good luck
mike
March 2008
I can answer this question...
HOW CAN I FIX MY CRAFTSMAN MODEL 917.387490 6.75 PUSH LAWN MOWER?