Thanks for this thread.
I changed the O ring and was testing to see if the siphon pump worked properly now. As it turns out, it was. I ran out of gas on an off ramp today near work. Between the 3+ gallons from the red gas can a guy from work brought and the 22 gallons at the station down the road, I proved it runs all the way to empty. I just need to figure out why my level indicator stops and sticks just a shade under 1/2 tank so this doesn't happen when it's in the middle of a snow storm. I had the transfer pump side pulled up for a bit when I fixed the O ring and possibly got the level sensor arm twisted or caught on something in the process of putting it back in?