Honda Common/Ground

[BlueH2Obound]

Lots of "Neutral ground bonding plugs" available out there. Here's just one:

https://www.amazon.com/Portable-Inve...0087166&sr=8-6

Honda also sells them, for a lot more $$$.
The one above is designed to plug into the 2nd output receptacle, or you can use an in-line one, also readily available.

I made my own. We used two Honda EU2000 generators in parallel on our motorhome when we wanted more AC than the small inverter put out, but we didn't want to start the diesel Onan.
It was required because the onboard EMS would show a fault and not allow the generator to provide power to the motorhome unless we bonded the neutral to the ground.
Worked great. We don't use the Honda's on the boat, but I wouldn't have any issues with it, storing the generator and gasoline in an on-deck, ventilated locker, just like I store the extra dingy fuel.