I have one of those old Cushman Truckster things, like the industrial work cart for the golf courses. Has an 18HP OMC opposed twin. I bought it 3 years ago and filled it with fuel (holds about 5 gallons). Backed it off the trailer when I got home and let it idle, then went to unhook the trailer and got a phone call to come into work. Came home 18 hours later to find it still idling in the driveway, still full of gas. Hour meter doesn't work but I KNOW there's upwards of 100 hours of run time on it, kinda just figured it ran on air as I've never had to put fuel in it. Until a few months ago, drove 2 miles to the neighbor's to drink beer and halfway down his half mile long hill, no more gas. Bone dry. Had to call my brother to come bring me a gallon to get home. Come to think of it, it's still running on that gallon lol