Starter Issues

Yesterday when I went to start my 916 iS all I got was a "click" from the starter relay.  I removed the glare shield and verified power at the output of the starter relay.  Then I removed top and bottom cowlings and verified power at the starter.  Apparently the starter had stopped at a "dead spot" and wouldn't turn with power applied.  I tapped the starter a bit to get it off the dead spot and was able to fly home.

Has anyone else experienced this?  Is it common?  Should I get a new starter?