Sounds like the blade hasn't had normal maintenance. I usually put a 2x4 into the grass chute to block the blade from turning. Without a mower jack, just a couple of 8" concrete blocks will hold the front end of the mower high enough to get the necessary clearance to use a breaker bar with a 6 point socket. Never use a 12 point socket as they have less contact with the nut. You can use a a hammer or mallet to hit the breaker bar.
After you get the blade off, be sure to put anti-seieze on the threads to prevent this problem the next time you remove the blade.
Good Luck,
Ken Donald kd51145@yahoo.com
Ken Donald, August 2008
