Chris wrote:

What is air lock?

Thanks,

Chris


Air lock can be different things, but occurs when air somehow stops
a pump or drain. Air lock in a suction line may be simply an air
leak in the line, or may be a partial vacuum in a sealed tank of
fuel caused by not letting air get into the tank to relieve the
vacuum. Air lock in a drain won't let water out of i.e. your
toilet, when the drain vent, on the roof of your house, gets
plugged with snow, ice, leaves or birds' nests. The overpressure in
the drain line can impede the evacuation of the water.

Vapour lock is when fuel in the fuel line boils and acts the same as
if you had an air leak in the pump suction line, preventing a pump
from reducing pressure in the intake line sufficiently for ambient
atmospheric pressure to propel liquid to the pump.

Terry K