Tractor battery won't charge

I have a Briggs 23 hp on a lawn tractor that isn't charging. I tested the battery and it was at 11.5 volts. I turned the engine on and tested it, still*11.5 volts at the battery. Next I disconnected the yellow wire at the voltage regulator(only one yellow wire)*and tested the stator and it was putting out about 40 volts AC so I hooked it back up. I* then disconnected the red wire and tested the voltage coming out of the regulator and it was about 8 volts. I replaced the regulator with an aftermarket one*thinking it wasn't putting enough out. Retested everything and got almost the identical results with the new regulator. Still only putting out about 8 volts. What am I testing wrong? Thanks for any information.
Model 446777
type 0763 B1
code 100504 G

 

When you checked the stator, was it from each leg to ground or across the two legs? Might be a bad regulator, I never had much luck with aftermarket engine electronics.

 

There is only one yellow wire so I tested that wire and grounded the other lead. I'm not sure about the after market part however it would be strange if both the old part and the after market part both were defective and read 8 volts each. I'm thinking that maybe the 8 volts is okay and that something else is in play. Someone else said that the 8 volts was only a sensing voltage but there should be over 12 volts at the battery. I'm now wondering if there is an inline fuse or a corroded connection. Without a wiring diagram or another motor to compare it with I'm in the dark. No pun!

 

You will need the wiring info for the tractor not the engine.

 

If you have over 30 volts on EACH of the two wires going in, and only 8 on the wire coming out, then the regulator is bad. 8 volts is not ok, it's not a "sensing" voltage. Sounds like something someone made up.