Small Engines (Lawn Mowers, etc.): lawn tractor ignition, soleniod, safety switches

Question
I have an old Gilson with 11hp Briggs.  Have not started for 2 years.  Last time I recharged battery it started first shot.    
This year nothing.  Replaced solenoid and switch.  Solenoid   
clicks fine when power to small terminal but creates a loud buzzing sound?  Jumped power to starter.  Starter spins but does not rise to engage teeth.  Motor spins freely by hand.
All safety switches and mowing attachements are removed as tractor is only to be used as snow plow, if I get it running.........  

Answer
 Hello Warren:

 Replace the Starter and the Soleniod. From what I understand; the Soleniod is Buzzing but the Starter doesnt move unless you jump Straight to Starter. Then the Starter Turns but the Drive gear Doesnt Engage the Flywheel. The Soleniod was going Bad and Burned the Brushes in the Starter. Hope this Helps.

 Good Luck

 Respectfully

 John