Intermittent start problem

[ARAKND1]

On my 1984 Spider I have an intermittent start problem. When the car is hot, say after driving for a couple hours in 90 degree + heat the car sometimes will not start.

When I turn the key there will be either a delay before the starter turns over or it will not turn over at all. There is no solenoid clicking as you might hear with a drained battery. It does not necessarily follow shut down with the auxillary cooling fan running.

The starter and bettery are sound. I have cleaned various grounds. What I find particularly odd is that it occurs only when the car is very hot.

Any thoughts or comments? Suggestions?

Dennis