Small Engines (Lawn Mowers, etc.): tecumseh engine on lawnmower, engine numbers, proper key

Question
My lawnmower which is 7 years old from Sears will not start.I have replaced the spark plug,changed the oil and air filter.
Symptoms:When I try to start it,after first priming,it seems to be fairly easy to turn over,via the pull cord,after a few times of pulling,trying to start,it makes light popping sounds.
It is a Sears model 944.367161,5.5HP bought June 9 1997
Thanks for any help
Don

Answer
It sounds like the flywheel key might be sheared.  You will need to remove the flywheel nut to inspect.  If it's sheared, take your engine numbers to a dealer and replace with the proper key.  You didn't say whether it actually starts or not, so I will assume it won't.  If you have any other questions, please write back.  Hope this helps.