How to determine whether Starter is bad?

Dave,
Later today found that where drive gear from starter engaged-- "flywheel" gear on engine has plastic teeth, CAN YOU BELIEVE IT.... starter drive gear had chewed out about 6-8 teeth...mmmm..mmm, I can still use it ok though, if it stops on this spot all I have to do is manually turn engine just a little and I'm off and running again!!
This Murray is 11 years old, maybe and few more miles left in it yet!
Thanks Again for your help

Walt
September 2008

Thanks Dave,

I'll be able to check to see if it's siezed later today, if weather allows. No prior problems like this in past, I did stop on an hill facing down, turned engine off-then when I tried to restart is when the starter wouldn't engage-it did attempt to engage, but I guess the driver gear would not. I'll check engine as you suggested, if that's ok I'll check to see if helix with gear is ok.
Thanks Again,

Walt
September 2008

If by 'hums' you mean it still turns but the engine doesnt then its the starter driving dog (which is plastic by the way) . If it hums but doesnt turn then maybe the battery is low and doesnt have enough power to turn it over. If the battery is good and the starter os good then the engine might be seized, try turning it over by hand with the grill bit ontop of the flywheel, if this doesnt turn then its is siezed.

Dave
September 2008