Here's the run down..

96' evinrude 115 on my 96' ranger bass boat

Cranking battery is good, but doesn't charge. I run across the lake a few times and battery is dead.

I've tested the battery and it's good.

When the boat is running it is drawing amps. Starts out around 12 and goes down. If I'm not mistaking, it should go up to 14 or so when the Motor is running.

Is there any way to tell if it's the stator?

If so, how much to get fixed you figure?
Thanks in advance for the responses.

Most likely the regulator is bad. You can tell if the stator is putting out voltage with a simple test light. Check the yellow wires to see if the have power while running. Just looked and this motor shows to have a rectifier and a regulator. Without a DVA meter, it is hard to perform the test. http://www.cdielectronics.com/technical-support-documents/

If you need a new stator for your engine they average about $300 I believe. Not sure what labor to change is though. I had one changed on a 150 hp many years ago and it costs me about $800 turnkey.

Is tach working if not could be rectifier