First of all you should made sure that there isn't any piece of string or rope wrapped around the blade (happens a lot if you use your yard and have kids :-)).
If that doesn't fix it, I guess the bearings on the top part of the shaft (the one that the pull start turns) is in need of some oil. Simply remove the bolts that attach the entire top cover, including the pull start. The top part of the shaft should have a square metal cap that has a tiny hole for oiling the bearings. Drop in some oil!
Answers & Comments
First of all you should made sure that there isn't any piece of string or rope wrapped around the blade (happens a lot if you use your yard and have kids :-)).
If that doesn't fix it, I guess the bearings on the top part of the shaft (the one that the pull start turns) is in need of some oil. Simply remove the bolts that attach the entire top cover, including the pull start. The top part of the shaft should have a square metal cap that has a tiny hole for oiling the bearings. Drop in some oil!
I sure that this will help :-)
Good Luck!