@andrewwynn do you happen to have a source/link/ part number for the O ring?

I’m fairly confident that I have a problem with my siphon pump now. Car seems to run fine with the fuel level always kept over a half tank and running it down it 1/4 to 1/8 saw it cut out while driving along.

I’m hoping it’s just an O ring that needs replacing as per the above example too.