Display MoreNot being familiar with the circuit and being at work right now I can't go look but the starter circuit should be relatively simple to troubleshoot.
Battery Good=Check
Grounded Good=Check
Engine Grounded To Chassis=?
Fuses Good=Check
Clutch Switch Good=Check
All Wires On Starter Tight=?
Used A Two Wire Momentary Button To Activate Solenoid On Starter=?
Taken Starter Off Vehicle To Bench Test It=?
Bottom line, if you apply 12vdc to the large post on the starter (not on the solenoid) and the starter has a good ground that starter motor should spin.
If you have 12vdc applied to the large post on the solenoid and you apply 12vdc to the small post on the solenoid and the motor is grounded properly the solenoid should pull in and transfer power to the starter motor causing it to spin and causing the bendix to engage the fly wheel. Either something is not grounded properly or the voltage is not making it to is desired destination. A simple volt meter can go a long way in helping you diagnose the issue but always remember that voltage it not amperage.
you forgot the starter relay
and get a real battery ...