Every Gasoline or diesel fire does not require a foam setup.
If the size of flammable liquid fire is within capability of an extinguisher you may be able to quickly mitigate the incident.

The number before the "B" extinguisher rating represents the square feet of flammable liquid fire that a "non-expert" should be able to suppress.

10B extinguisher is rated for 10Ft2
20B extinguisher is rated for 20Ft2
40B extinguisher is rated for 40Ft2
80B extinguisher is rated for 80Ft2

The "sweep" motion and application point is crucial with flammable liquid fires.
Sweep the stream at the leading edge of fire, gradually painting the surface and focus extinguisher product where fuel vapors are igniting.
Focusing predominately on the flames will waste product without success!

Extinguisher product DOES NOT provide a film or foam barrier so fuel vapors may continue to reignite. Be prepared with more extinguishers.