Filling Up Tank Puzzle

[Bhatti, Mohammed]

Ok, I remember Dan S. posed this puzzler way back, maybe 3 years ago and
I've been always meaning to ask what the solution was but never quite got
down to clacking the keys on the keyboard (procrastinators of the world
unite...um...maybe next week).

Anyway, Dan posed the question: when filling up the gas tank on 80/90
models, why does the handle on the pump deactivate almost immediately when
held in the 6 o'clock position but works fine when in the 10 to 11 o'clock
position?

So Dan (or anyone else), what's the answer?

tia

mkb
88 80q