It looks like a dual post rather than 4. So it may be connected internally. Take a 12 volt battery and connect up to the two large terminals on the motor and see what it does? Can you take the cover off to have a look at the commutator and get some photos. This is nothing like I have. Mine is larger.
Go to youtube and look up gottdi and onegreenev. You will find my videos and you will see a few with the Starter Generator.