Water In Fuel (or possibly an overactive imagination)

I put this here because it isn't automotive.  It's an old Tecumseh 8.5 hp flat head from the early nineties.  At this point I think it may yet outlive me...

I haven't been posting for some time because I now have a manageable number of cars and they haven't been breaking!  I still try to read the forums because you can't be lucky forever.

I owned an aircraft for just over 20 years and I tested for water in the fuel every time I flew it.  I never found any, even when it was tied down outside and horrible storms came through (Oshkosh).  Still I'm aware that it can be a problem.  Anyway, you drain from the lowest points to find water.

I did some work on the Tecumseh last month.  Nothing with a float gets to set overnight in my garage unless it has a fuel shut off valve.  I added one.  It also seemed like a good enough time to install a fuel filter.  I suspect that the next part is important.  There was not enough room to put a filter on the line.  I put a longer fuel line on (that dipped down below the carb) and put the fuel filter at the low point (because there was room in that spot).  Plug, oil change, carb rebuild, etc., and the thing ran fine.  Then it sat in my shed for a month while I recovered from some surgery.  I pulled it out of the shed last week and no joy, it would not start.  On the bottom of the bowl I pressed the little springy valve thing that lets you drain the fuel.  The bowl was empty.  I disconnected the fuel hose downstream of the filter and tried draining the fuel into a glass jar that had some fuel in it from another project.  Nothing came out.  My fingers slipped and the filter hit the rim of the jar and something flew out of the filter and into the jar with a plunk.  I continued draining just in case there was more.  Then I looked into the jar and found nothing.  I mean, if the plug was gas soluble it wouldn't be a plug, right?  I carefully poured most of the jar's contents into my fouled fuel container and left a small amount.  There was like a small amount of something heavier than gas on the bottom that you could barely see.  It did not coalesce into even a single drop but hugged the bottom in a pitifully thin layer that slightly lensed any light passing through it just enough to let you see that something was there.  I poured the rest out of the jar thinking maybe I was imagining things.  The bowl on the carb filled.  Then the engine started on the first pull.  WTF?

Do you think that a small amount of water could have lodged at the low point of the fuel line and caused this?  It's a gravity fed fuel setup so there isn't a lot of pressure pushing it into the carb.  Or am I thinking too hard and maybe missing the obvious?

Could whatever hit the jar have not actually gone in and just bounced off the jar?

I don't think so but thanks for reading all of that. It definitely made a kind of kerplunk sound. This one may have to remain a mystery for me...

It's looking like my 'improvements' caused the problem. It happened again, no start, no fuel in the carburetor bowl, and getting too old for a recoil start on an 8 HP motor. I removed the fuel shutoff and the filter that I installed, then routed the hose the way that Tecumseh intended (fiddly but a shorter run than the mess I had created). The bowl is full of fuel every morning and it starts on the first pull.

When I'm not busy some day I'm going to sacrifice half a pint of fuel by putting it into a clear jar and adding a few drops of water. I expect that it will bead into droplets on the bottom as I was taught.