check the battery voltage if ok check the solenoid pull-out the starter from the unit. make the body of the starter as a ground then connect a jumper cable to the terminal 30 sometimes the terminal 30 looks like a mounted bolt.
Then when the negative terminal are already connected to the ground of the starter so as the positive to the terminal 30 the starter pinion gear will move forward and if it is not replace. And also check the contact tips of the starter it might be worn-out replace it...then inspect the carbon brush of the starter......good luck!