J;

In general terms, having all clean and tight connections as Al suggests is not a bad thing, but more specifically, the question you need to answer is: Is the Solenoid getting power when you depress that Start Button, and working as it should?

I suggest you have a helper push Start Button as you listen under the hood for the solenoid CLACK (Out of gear, Handbrake applied!)...if no CLACK and Starter turning occurs, check for 12V at Solenoid term 50 when button is pushed...if not present, Starter Button and associated connections are suspect.

If 12V is present, but Solenoid does not CLACK, or only clicks and Starter does not turn, Solenoid is either sluggish or High Current Contacts (HCC) are carbonized and not making good connection to route power to Starter.

See: http://www.sw-em.com/starter.htm

Good Hunting!