Generac quietpact 40G has no output- need help

yes a genset can loose 'residual' magnetism of the core
but this is a slow process, sometimes taking years
it is NOT the likely cause of his problems

he will need to wire an outlet to the generator connection box
or the input side of the TS

without power the TS is open, the RV outlets are NOT connected to the generator when the TS is open

so there is no outlet he can use until he makes one