Stale gasoline is most commonly associated with which smell?

Stale gasoline is most commonly associated with a varnish-like smell. This odor arises as gasoline sits for an extended period, leading to the evaporation of more volatile components. As these lighter fractions evaporate, the remaining fuel becomes more viscous and has a distinct scent reminiscent of varnish. This change in odor serves as an indication that the gasoline has degraded, making it less effective as fuel and potentially harmful to engine performance. Recognizing this smell is crucial for operators to avoid using old fuel that could cause starting difficulties or increased emissions in outdoor power equipment.