Volatility is a fuel ability to turn to vapor. Gasoline
must vaporize quickly after it is mixed with air in the
throttle body or intake manifold. Otherwise, drops of
liquid gasoline enter the cylinders that will wash the
lubricants oil off the cylinder walls. This increases
wear of the cylinder walls, piston and rings.
• Gasoline that does not vaporize will not burn. It
leaves the cylinder in the exhaust gas and pollutes
the atmosphere.
• Too low volatility makes the engine difficult to start.
• Too high volatility may cause the vapor lock in the
fuel line which stalls the engine or stop.