Thanks much to all you guys for the help and tips (and good stories of your own experiences!).

Well, I went back over there today and sure enough - all it needed was more gas! This was after I confirmed there was still gas in the tank. Once I added the new gas, primed and eventually got it to startup, it ran like a top.

So, it looks like in my case at least, the pickup doesn't reach the bottom of the tank, though I guess I'll never know for sure how much gas it needs in the tank before it will run??

I do know it's the correct sending unit (as I have replaced this once before in trying unsuccessfully to get the gauge to work). Looking at the shape of the tank it sure does seem possible that you could have gas in there that doesn't get picked up!

This was a good learning experience though. I'll never let it go under 1/2 full again (as best as I can estimate where that is). Thanks again for the all the good insight!