Best use I think of the unregulated 12v outlet if your determined to use it is to make it run the ventilation fan.
I think your grossly underestimating the amount of heat there is to remove, this blower is used on my Nexgen, and it’s a
water cooled engine and exhaust, so only the generator is air cooled and it still get the air so hot that it will collapse a blower hose.
I had to use high temp aircraft SCAT hose which is also smooth bore so it flows lots more air.
https://www.westmarine.com/jabsco--1...12_362_001_506
The Honda is a smaller 2.2 as opposed to 3.5, but it’s engine is also air cooled, and even more so the exhaust
muffler is air cooled.
I would imagine the Honda gives off significantly more heat than my Nexgen, and of course that heat has to be removed.
That fan is only 150 CFM. My guess is you would need 250 CFM and if you go with 12V that is about 13 amps roughly.
However if you go with 12V it should also of course function as a blower to remove explosive gases, but then you need to run it from the bank.
Surely the 12v circuit isn’t “free” power, it would I think come off of the generators power.
Being above deck of course surely makes it safer, but as it’s no longer a portable I believe you will still need to meet regs, ones that I can think of are.
Flame arrestor, that is just a
screen on the intake and may can be purchased. Or fit a K&N airfilter, they are certified as a flame arrestor, I know this from my Jet Ski days.
Engine and generator be ignition protected, it’s still in an enclosed space. Maybe Honda has certified it as so? If not I don’t believe this is one you can pass.
Fuel system? I know if below decks you need to at least change fuel hoses, above deck in an enclosed space? I don’t know.
Exhaust in my opinion needs an insulated wrap, probably want to do that just to keep more heat out of the box anyway.
I think Franzisca’s way is the most logical, find a nice box, leave the top open when you run it.
Sure solves a lot of problems