Small Engines (Lawn Mowers, etc.): lock nut, stuck nut

Question
I have a Husqua.. 125E straight shaft edger.  I can't get the lock wash nut lose to remove/replace the 7" blade.  please advise.

Answer
Have you tried turning it the opposite direction?  It may be a left-hand thread.  If not, I use PB Blaster to loosen frozen nuts and it works very well.  Other than those two, applying heat will sometimes work but this will be difficult because there's a rubber seal right behind the blade most likely.  Try these and let me know if you have any trouble.  Thanks, PK.