First, check for a bent blade.
To do this tilt mower (gas side up, oil side down) on one side and observe blade. Try to rotate it to see it it's hitting anything.
If it's not the blade, and it's vibrating severely and/or making banging noise, it's probably a bent crankshaft. You'll have to have it replaced, or buy a new mower.
getterdun
July 2010
You may well have bent the crank, remove the blade and carrier put a straight edge against the crank at different points to check for bent crank
Husqvarna man
April 2010
Automatic Answer
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