Originally Posted by
Pilot DAR
If the accelerator pump squirt is drawn up the induction by good airflow (running engine), it gets to the cylinders as intended. However, if the airflow is poor, and gravity good, the liquid fuel will just drop down through the carb, into the airbox, and pool there. Once the accelerator pump fuel has dropped into the airbox, it is of no use as priming fuel, and the start may fail.
A cold Lycoming O-360 will not start unless the mixture is richer than delivered by normal cranking air flow through the carburetor. The fact that a cold Lycoming O-360 will start easily with a couple of cycles of the accelerator pump, while cranking, shows that the fuel delivered by the accelerator pump did in fact richen the mixture that was drawn into the engine. If it richened the mixture drawn into the engine then the cranking airflow must have been sufficient to overcome gravity.
Can we please stop assuming that fuel delivered by the accelerator pump while cranking will pool in the air box.
I have flown about 40 different powered aircraft types and not set any of them on fire. Always open to learning from those who have though. What exactly were the steps you followed to set fire to your C-150? Hopefully we can learn from that unfortunate experience.