The starter was making noise and didn't seem to be turning the engine over as fast as it used to. I pulled the starter apart and it has a bushing at either end. I couldn't detect any play but there is play vertically. The armature can move 1/8th inch up and down. There's only one washer on the bottom and two on the top. Should this be tighter?
This starter only has a small drive gear on top so I guess the flywheel drive gear should be looked at as well.
This is only a suggestion. The brushs that make contact to the armiture may need a bit of cleaning. Also, check that the brushs are still good and don't need replacing. If they are almost worn out it could be your problem. You can always send it out for a rebuild if you're not sure what to do.
Thanks Andre, the brushes are about 1/4 inch remaining. My manual indicates to replace at 3/8 inch so I guess they are due to be replaced. They look simple enough to replace. There was lots of dust in the bottom cap, likely the brushes.