It was working fine, 4-5 weeks ago.   Went to turn engine over....click.  My thoughts are as follow.  All voltages are 6.3V   from battery through starter solenoid down to starter post.    Battery, cabling are good.  I'm willing to bet........ first....I've lost a good ground connection from starter to block  and  second.......the starter has gone bad.    I would like to add a ground cable from starter to block.  Any thoughts?