Hello P.,
If the wiring does not resolve the issue, consider the following:
I suggest you pull the flywheel and clean the underside really well along with the stator. Inspect the stator for green spots where the shellac coating has failed.
The other possibility is some of the flywheel magnets have come unglued and bunched up. When that happen the stator output is reduced.
At high RPM without PTO activated, this should be putting out better than 14.5V.
Teryll Fixes All (YouTube) has a great video about how to identify the magnet polarity and reattach them using JB Weld, spacers and light clamps to hold them until the JB Weld sits up over 24 hours.
