it mainly leaks from the vent valve, my dad flipped it up so it couldnt leak down, idk why lol, but thats when it filled up my engine but idk where all the gas came from cuz it was definitly more than a floatbowl full, and im 90% sure it doesnt leak once its running cuz ive had it idling in my driveway for a few min and didnt see anything