GT 3000 Won't Charge

[Mattmotors]

Details: Sears Craftsman GT 3000 917.275042 Serial 012402A00129 With a Kohler CV675S Spec 75544

I was cutting the lawn and noticed the amp meter was on the negative side. Not charging. Let me explain what I have done so far to trouble shoot.
1. Removed connector from regulator and measured output of stator. I have about 28 volts AC at full RPM
2. Connected regulator and measured output on middle connection. At full RPM I have 15 volts DC.
3. Measured across the battery, Everything connected, Full RPM. 12 Volts DC. Not the 15 volts like at the regulator.
So now I'm thinking I have an open wire on the regulator output wire some where. Next test:
4. Pulled Regulator plug and disconnected battery. Put an OHM meter on the positive battery wire (disconnected from battery) and the output wire (middle wire) and measured. No continuity (key off). Turned key to on position (posts B and A1) and I have continuity.
I put everything back together, started tractor. Ran at full RPM. The Amp meter didn't budge. It use to come up on the positive side while the battery would top off. I'm stumped. It's not making sense to me. Looks like everything is in its place. I will be sleeping with the wiring schematic under my pillow tonight. Please advise. Thanks , Matt.

 

[hlw49]

Check the voltage at the center wire (charge wire) of the regulator without the engine runing and switch off and then on. See what you get then. I have done this and would read voltage but still not charge. When I find one like this I run a wire from the charge wire terminal of the regulator straight to the battery plus terminal or plus side of the solenoid. It works and will not run down your battery. Not wasting time trying to run down an open wire.

 

[StarTech]

Note what could the problem is a bad F56 terminal. IE loose fitting and it can be at either the regulator or the ignition switch. Just repaired a system with bad f56 terminals at the regulator. It actually tested good recently but the mower was still loosing the charge voltage as the terminals moved around.

 

[Mattmotors]

Success!! What I did was took the regulator off and sanded the terminals. I also have a ground wire under one of the screws and I cleaned that one too. Reassembled and checked. Came right back to life. I believe I added the ground wire from the case of the regulator to the frame of the tractor on a previous repair. Thats when I discovered all the magnets popped off the flywheel and were stuck to the stator.
Thanks Star Tech and hlw49 for your input and direction. Matt.