We all know the old "tap on the dying starter" trail/street fix. But what are some of the actual causes of the problem?

Ive got a 95 s10 4.3 with this problem. Easy fix right - pull reciver hitch out, crawl under truck, hit starter with shinny ball, turn key and be on my way.

Either the solenoid is crappy/carbon'd up or the brushes are not making good contact.
Either way you can pull it, clean it and bend the brush springs a little more and be good to go for quite a while. and save yourself $100

The washer for the hold in winding often goes to shit with corrosion and damage from arcing and doesn't make good contact. You used to be able to get them off the shelf at any parts store, but good luck now. If it's a small block you're better off just spending the $40 on a reman starter with a lifetime warranty.

I will try the pull and clean tomorrow. If it still doesnt work properly will a SBC starter interchange with a 4.3? I have 2 laying around.

Bringing the semi-useless tech.
Well It works now and it was the brushes, they fused to the cummutator. Took it apart filed every thing smooth.
http://i577.photobucket.com/albums/ss211/gmcxt/brush1.jpg
http://i577.photobucket.com/albums/ss211/gmcxt/brush2.jpg

And yes a small block starter worked in my application. But I have the early 4L60E with the removable scatter sheild. So It may not work for everyone.
V8 on the left V6 on the right.
http://i577.photobucket.com/albums/ss211/gmcxt/front-1.jpg
http://i577.photobucket.com/albums/ss211/gmcxt/top.jpg
The V8 starter is bigger and the solenoid sits right next to the manifold. A little too close, plus it didnt have a heat sheild. But it worked. So next time yours locks up take it apart and save some $$$