When I was about 16, I did a tuneup on my sister’s Renault 16. I changed the fuel filter. Of course, every good mechanic checks to see if it leaks by starting her up. The fuel filter was way down low. So, the car is idling. I get a flashlight, shine it on the filter and stick my head way down there. Yup, it’s leaking. And woomf! Smoking eyebrows and my sister’s car is running and on fire.
Luckily, I shut it off and put the fire out before too much damage occurs. Just some melted wires. However, I learned that a distributor is a good ignition source, and not just in the cylinder.