I'd like to impart a bit of information, on the indoor storage of gasoline powered equipment.
Gasoline fumes will tend to stay low and "hug" the floor, if the tank or a line should leak when the machine is stored inside!
When i built an addition onto my house, i had the floor made 2 blocks lower than the existing cellar floor. This way, if i should have an inadvertant gasoline spill, or gas fumes are present, they wouldn't "light up" the rest of the house. The smell of gasoline fumes does not necessarily mean that an explosion or fire is imminent, but should make you think about neutering any possibility of the fumes gathering in an enclosed place! Or an ignition source!
Naturally, you should try to make sure that nothing has any tendency to leak over night, before you leave it!
This stood me in good stead one day. I forgot to tighten the clamp on a fuel pump outlet hose! It popped off and pumped about a quart of gasoline out onto the floor. WOW!!
But, the fumes never made it to the hot water heater on the other side of the door! They laid on the low floor, until i could sop up the spill!
I don't remember what the ratio of gasoline smell/fumes is to subsequent ignition, but you would need a large accumulation to cause any problems.
This info comes from Fire Company training and other sources.