Problems starting when engine is warm

[Steinerj56]

When I am trying to start my truck after driving for any period of time and the engine is warm it acts like the battery is dead and the engine barely turns over if at all for the first 5-10 seconds.

If I hold the key to the start position... knock on wood... it always starts but seems like it has a low or dead battery.

Got any solutions or ideas? could it by hydro locking when warm and shut off? fresh rebuild, 250 miles on engine rebuild.