The last mechanical pump I had in my Pontiac Tempest filled the crankcase with gas when it failed. On the upside, hey it did clean out the inside of the engine really well! :-D However the Tempest four requires a fuel pump with a smaller diameter than the V8, because of the narrow frame rails, therefore none of the aftermarket Pontiac pumps would fit, even though the armature and mounting (and the sand cast front cover they bolt to) is exactly the same as a V8.
I went to an electric pump and plumbed it into the park light circuit so I'd always remember to turn it off. After the initial time I didn't remember to turn it off, it filled the cylinders with gas, then when I removed the spark plugs and cranked it, there may have been an underhood fire in front of the local diner.. Fortunately they had a fire extinguisher, I could sprint pretty fast as a teenager, and the only damage wound up being to my pride.
