The answer is yes. We had a Polar Cub mounted on the roof of the Tom Cat. The Honda EU 2000i was on a plastic crate on the engine bracket. We had a 6 gallon outboard tank to run the generator all night, if necessary. It will run about 4 to 6 hours depending on cycling if you just use the internal tank.
Currently we have a Honda EU 2200i. The most recent version--and definitely better. Also there are the "Easy Start" systems for the RV units which require less power--and better start up.
As long as the fuel tank is within a foot or so of the level of the top of the generator, it will siphon fuel over, using the generator's small fuel pump. I have seen some try and connect directly to the pump--check out the RV forums for this.
We have also, more extensively used a 5,000 "Arctic King" cheap window air conditioner in the opening front window of both a 25 and a 22. These will run off the EU 1000i generators. Our boat came set up with a bag for the
ac unit and mounts on the bottom, so it is easy to put in place and set up. The 5,000 unit will bring the temp in the 25 to 20* below ambient. It will make what is not comfortable--comfortable. We are debating to put an RV type on the roof. It is more convenient, but also makes it harder to carry a dinghy on the roof--which is essential for us, because of a dog.
I don't find the noise of either the air conditioner or generator objectionable. In some cases the Honda is quieter than some built in generators. One caveat; You must keep the exhaust out of the boat. You must have at least 2 Carbon Monoxide alarms. We have 3. One by the helm at head level. One by each of our heads in the bunk. Our 25 has the port bulkhead between the cabin and V Berth removed. Better air circulation. We also have two fans near our heads to move air around the V bunk--as well as a couple of fans in the cabin.
