hello i have a 1997 f250 7.3 and the engine cranks over real slow, plenty of juice going to starter and batteries are fresh.i was just wondering if starters get tired as i just replaced one on my jeep cherokee and now the new starter turns the engine over almost twice as fast.

 

Yes.
The brushes and armature eventually gets a bit...dirty.

I tore mine apart and cleaned the armatures and the brushes as well as repacked the gears/bearings. works great now.

The spaces on the armature get clogged up and will start to arc the coils together.
I didnt' clean mine out correctly though.
I should have re-epoxied the channels so they would not collect anything again, but it was cold out and I needed it.

 

yes they do "get tired"

this is my 88 with a bad starter at 70 degrees


and here is the same truck at 40 degrees with a new starter.


click on the picture to play the videos.

 

yeah mine sounds just like or worst than your first video tjc.time to replace.

 

it is amazing how easy they start up with a good starter in them