Starter problem?
 

1951 Chev, S10 swap, 327, auto trans. I thought I was having alternator trouble based on a test at the local parts store. Turned out my alternator had gotten a little loose so the belt was slipping and the battery wasn't charging correctly. Easy fix. Took a nice long drive, shut it off, tried to start it and it would not turn over. Jumped it and it started right away. I had the battery tested(it's only 3 years old) it was fine. I tested the alternator with a volt meter, putting out 14.8 at the back of the alt (single wire). Voltage at battery while running is 14.6. The voltage at the battery with the truck turned of reads 12.8. Shouldn't that be enough to turn it over? Is it possible that the starter solenoid is bad? Or maybe a bad connection at the solenoid? Would the extra 1-1.5 volts from jumping it make a difference? I thought if the starter/solenoid was bad, it wouldn't start even with a jump.

Re: Starter problem?
 

Let it sit overnight or for a few hours and check the battery voltage again w/o starting. A better description of what it does or doesn't do would help.

Re: Starter problem?
 

My guess might be heat soak at the starter or solenoid, based on it not wanting to start hot, happens with age (or crappy new starters). I'd swap out the starter and solenoid and see if that fixes it and install a heat shield between the exhaust header or pipe and starter. Could also be a bad cable between the battery and starter, they can look good but be corroded where the terminal connects inside the insulation.

Re: Starter problem?
 

I'd think pretty much on the line that OrrieG is but rather than spring for complete starter I'd just pull it apart and replace the bushings and brushes if it were mine. Unless that isn't enough to fix it to go another round that is. Most of the time the bushings get worn just enough so that the armature drags a bit when the engine and the starter are hot =heat soak and eventually the starter doesn't want to turn the engine until it cools off.

Re: Starter problem?
 

Mr48, I just assumed everyone that has old Chevies has 2-3 starters laying around like I do....

Re: Starter problem?
 

All good info. I'll look into the starter and I may need a new battery anyway. Thanks all.