Perhaps the most common type of piston engine aircraft fire is one that erupts during engine start. A typical example would be as a result of over priming for start-up, resulting in excess fuel in the cylinders.

Any engine fire in a single engine piston can result in flames and smoke entering the cabin via the hot air vents. During engine start-up, good practice would be to keep the vents closed.

Further information on dealing with engine fire can be found here:

CESSNA 172P HB
EMERGENCY CHECKLIST
Cessna 172P HB CQL Page 1

FIRE ON GROUND
DURING ENGINE START
1 Cranking ------------------------------------------------ CONTINUE

IF ENGINE STARTS
2 Power ---------------------------------------------------- 1700 RPM FOR A FEW MINUTES
3 Engine --------------------------------------------------- SHUTDOWN & INSPECT

IF ENGINE FAILS TO START
4 Throttle -------------------------------------------------- FULL OPEN
5 Mixture -------------------------------------------------- IDLE CUT-OFF
6 Cranking ------------------------------------------------ CONTINUE ( 2 to 3 Min.)
7 Fire Extinguisher ------------------------------------- OBTAIN / GROUND ATTENDANTS
8 Engine --------------------------------------------------- SECURE
a) Master Switch -------------------------------------- OFF
b) Ignition Switch ------------------------------------- OFF
c) Fuel Selector --------------------------------------- OFF
7 Fire ------------------------------------------------------- EXTINGUISH
8 Fire Damage ------------------------------------------ INSPECT FOR DAMAGE