Look At the Top of the Fuel Tank
I don't own a 365 but I have a 31-2 and my boat has a dial-type fuel gauge (very simple, unfortunately) on top of the fuel tank -- and nowhere else. I have to crawl into my quarterberth (next to where the fuel tank is located) and there is a small access cover that slides back to reveal the gauge on the top of the tank. Thought this was pretty primitive at first but, in time, I realized that sailboats use so little fuel that it's really unnecessary (but a nice luxury/gadget) to have a fuel send and gauge in the cockpit to monitor fuel consumption/supply remaining. I use my boat about 2 or 3 times a week and barely burn any fuel just going in and out of the harbor. I crawl down and look at the fuel gauge once every two or three months, just to make sure I haven't used up my supply. I'm betting your boat may be set up similarly. Take a look at the top of your fuel tank...Cheers!