Generator not powering cabin equipment.

I agree, call the people who rebuilt it.

Where is the fuse? Fuses are usually for the motor end of the generator not the AC output. I doubt that s your issue.

Small push to reset breakers are usually to protect the DC side of the motor. AC breakers are normally dual pole. It s been year since i ve used a gas gen though... but check around the control box, sometimes they re on the side

The generator was tested prior to delivery. That is why I think it must be a fuse or breaker or something like that. The breaker is a simple red push to reset that seems ok. Does the fuse on the Control box of the generator interrupt the 110 output or just the generators gas engine?

Sorry, I asked the question while you were answering me about the fuse.

All good input and I'll keep looking but so far I have not found any other breaker or switch. This picture was taken prior to the rebuild but the configuration is the same.

Your breaker in the picture is for the motor.
Who wired the gen set back up? There are many different strapings at these connects. Don't assume they are the same as when it left the boat. The builder may have changed the strapping for their own style of testing.

And, Yes, some older gen sets have ACv fuses inside the box.
You should also have a service breaker in the E R.