OEM parts are best to rebuild over and over -I don't suggest buying anything 'new'. But, seems you may have missed a step on your rebuild so don't be quick to blame the starter. Like Bruce (VA) said, click click click could be a weak or junk battery -get it tested at your trusty local starter/alternator shop. they can also test the starter. How old is it? The battery is the first step in any electrical system. It MUST sustain a full charge under load to be effective. Cheap wallyworld/tsc batteries are usually junk as well and last maybe 2 years. The 9N/2N starter is a 1-Wire unit that uses NO solenoid. Poor/incorrect wiring is a big non-starting issue to investigate as well. So, you don't say, but is system still 6V/POS GRN or a 12V switchover job? Lots to problem solve before replacing any parts.
9N/2N ELECTRICAL DIAGRAM, POST S/N 12500: