I was pumping cleaning solution in a 1/2 doz heater cores and killed an old stock fuel pump. Hmm lets try another, yup killed that too.
OK lets see what killed the units.
Interesting that the copper was removed by electrolysis and later the copper plated on the ground of the body. That is so cool..
As you can see it totally removed several copper contacts on the armature.
I now know that the fuel flows inside the motor.
Here are a few pictures for interest.
This is a 91+ pump