Re: Shore power issue
We had that same switch fail in a similar fashion on our Super Maramu. On the SM, this changeover switch is located in the engine room on the port side right outboard of the generator. It is in a gray electrical box labelled "Quai-GE" and "220 Volts" mounted on a wood board. See the attached picture (courtesy of Bill Rouse). I do not know if it is the same switch or is mounted in the same location on the 54.
We ended up replacing the auto-transfer switch with this manual break-before-make switch: https://www.bluesea.com/products/8357/AC_Rotary_Switch_Panel_65_Ampere_2_positions_%2B_OFF_2_Pole
It is a much more robust switch but it does require that you actually go into the engine room to switch from Shore Power to Generator Power. However, that is fairly infrequent and it has been pointed out to me that is not such a bad thing as I should be checking the oil before starting the generator anyway.
Hope this helps.
SM 440 Cara
Deale, MD USA