Thanks MST for your assistance. I have looked at the parts list for my engine and it seems that the newer versions of this engine did away with the counter balance. There are three pictures of the crankshaft and two show some type of counter balance as you suggested but after 1999 it seems there is only the crankshaft. There are no cracks in the chassis where the engine mounts, I might try some local repairers re. your suggestion on the flywheel or I may just bite the bullet and take the engine to a small engine repairer. I was somewhat annoyed at the reaction by most of the mower repair shops, it was basically you need a new engine it will be about $2000 please thank you.
