I highly doubt that the B&S is voltage regulated. Most likely a bridge rectifier also called a full wave rectifier.
The battery acts as the voltage regulator.
If the system is constantly over charging the battery, boiling it’s water away, you can disconnect a charging lead from the stator to the rectifier turning it into a half wave rectifier. . This will reduce its current output. Also a switch could be put into a lead. High voltage isn’t usually much of a problem unless you are powering fancy electronic devices like a chart plotter, etc.
Usually in a power supply capacitors are used to smooth or average the waveform. The low cost marine rectifiers that do not regulate voltage use the boat battery to smooth the waveform.
You may also want to look into a rectifier/voltage regulator like used on the OMC motors in the 1990’s. They are going to run you $100 or more unless you can find a used working one.
CDI electronics sells such regulators.
