Before you go replacing the voltage regulator I would chek the battery isolator and the batteries. If you have a shorted cell it could cause the alternator to push more. The batteries will only allow the alternator to push in as much as they can take. A bad isolator can cause the same type of readings and boil the batteries.
If the batteries are fine, then you may have a bad regulator or alternator. The alternator is not the normal one you buy at Autozone, so be sure to get an exact replacement, or have this one rebuilt.
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome
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