68 mercedes restarting problem
 

I just got a 1968 mercedes 250se and I am having a restarting issue. I will drive the car for about 10-15 minutes and then turn the car off. If I try to restart the car immediately it will not start. If I let the car sit for about 1 hour the car will restart. I have checked the battery and it is fully charged and it does receive current when the engine is running. I am trying to figure out if this an issue with the starter or if it is something else.