There should be NO interconnect at all between the generator and shore
power. If shore power is live your generator would provide an
interesting fireworks show. If shore power is out you could kill the
linemen working on it who are not expecting power to come the "wrong
direction". If you are going to plug a boat into the generator and
have it mimic shore power the neutral and the green ground wire would
be connected at the generator and the generator frame would also be
connected to these wires and a good ground. It sounds like the
generator is letting the neutral "float" in relation to ground. I
really don't know enough about the Honda generator to tell you if this
is dangerous or if grounding it the way I described might also be
dangerous.

Joe

ps - If it were possible to wire boats with a floating AC system I
think it would be much better, but we are stuck with the grounded
system.