A float needle leaking and letting gas fill up an engine could on some mowers leak out onto the floor. Should for example you have a gas water heater, the ~~~fumes~~~ could and possibly would drift over to the pilot light on the heater and KA-BOOM!! Instant fire, which is what happened to a neighbor up the road from me. He was out mowing and came in to refuel the riding mower in his basement. He was fueling it when the fumes hit the pilot light. The Instant explosion caused a conflagration that burned the house to the ground in a matter of minutes. He didn't think to turn off the gas supply and the natural gas only made it worse! So be careful about not refueling engines, or storing gasoline in the basement of your house!!