Have a John Deere L111 riding mower that won't charge the battery. I've replaced the original, thinking it was bad. After jumping with charger it starts up and runs entire 45min. While cutting grass, but once shut off, that's it. I tested battery after jumping and only seeing 8.5vdc. So the charging syst. Isn't working. The local mower repair shop said the stator is about $70 plus labor for around $300 total. I'm pretty mechanical and would like to attempt the fix myself as $ is tight but I never took apart a Briggs & Stratton engine, or any small engine for that matter. Can anyone provide directions on this repair or suggest where I could find something that would describe step-by-step, how to fix this?

Additional info: 8.5vdc on battery terminals was with engine running after starting with portable battery charger/starter. Turned off, and with positive cable disconnected, I put my multimeter in line and was seeing 0.3mA current draw with everything off. Unplugged run-time meter and still saw 0.3mA draw. Turned on headlights just to see draw and saw 30.3mA draw. Turned off and back to 0.3mA. I'm guessing that small of draw shouldn't affect battery and problem is with charging stator. Question would then be how to replace it. Thanks.