I have a 12.5 brigs twin engine that is not charging. Is there a voltage regulator, does the starter also charge the battery?

Yes it is regulated, and no the starter does not charge the battery. How old is your battery? The expected life cycle on most is only 1 year. And use a battery that has a cca rating of 300. Have you tested the battery with a load tester? If you use an ohmeter, it can show more than 12 volts, but as the load is applied, in this case attempting to start, then the volts can rapidly drop even all the way down to ZERO volts. I have seen this many times. And most people will assume it is the charging unit, and it was simply a dead cell in the battery. Have your battery tested with a tester that will put a load on it. Then let me know.

yes it is regulated, and no the starter does not charge the battery. how old is your battery? the expected life cycle on most is only 1 year. and use a battery that has a cca rating of 300. have you tested the battery with a load tester? if you use an ohmeter, it can show more than 12 volts, but as the load is applied, in this case attempting to start, then the volts can rapidly drop even all the way down to ZERO volts. i have seen this many times. and most people will assume it is the charging unit, and it was simply a dead cell in the battery. have your battery tested with a tester that will put a load on it. then let me know.

Yes my battery is newer, I have had to charge it twice this summer.
Motor is a 1995, I heard that this motor charges with stators or something to that effect.
I have worked on motors before, but never heard of a stator. Last I new the starter was also a generator?

Yes my battery is newer, I have had to charge twice this summer, so I am sure it is the charging system. I was told maybe this unit has stators? Don't know what that is or how to fix?

yes my battery is newer, i have had to charge it twice this summer.
motor is a 1995, i heard that this motor charges with stators or something to that effect.
i have worked on motors before, but never heard of a stator. last i new the starter was also a generator??
Yes, it charges by the use of a stator. A stator is essentially an alternator, that is located under the flywheel, it is a round device that has copper windings spaced out around the perimeter, and there are magnets located on the inside lip of the flywheel, as the rotation of the engine spins the flywheel around the stationary stator, it produces a moving magnetic field to induce current. To check the stator can be difficult to explain, you have to know whether to test for ac or dc volts. And how to hook to which wires. In some cases there is an external stator that is located alongside the flywheel. But you do not see too many of the external style.
I still feel you need to have the battery checked. Not to say that you do not have a problem with the charging unit, but most of the time it will be the battery.

If I was to check could I not do this at the regulator which I can see on the side of the engine. I did check the dc voltage at idle and full speed at the battery and I showed 12.56 volts, which needs to be 13.5 to 14 volts on a automotive engine. Should this not be the same for a small engine?

You need to go to a dealer and ask them to give you a copy of the diagram and SPECIFIC directions for testing charging system. And you have to have a load testing tester to test your battery. You will not get the results I am trying to tell you about using an ohmeter.