Bill, thanks for the idea.

That generated a number of ideas.

Del,

Thanks, your the second person to recommend that possibility.  I'll check it out this weekend.

Del or Mystery Guest,

The sender unit is on top of the tank.  Based on the parts manual its under a small cover on top of the tank next to near the gas cap.  Is that right?

I went looking for the leak.  I checked took off the inspection plates and the sheet metal strips at the root of the wing.  Couldn't find the path of the fuel leak?  It's very puzzling.  How does a leak from the sender get on the fuselage rear window?  Maybe some msyteries are not meant to be solved?

Barry,
It's possible you may actually have a problem with the tank itself. However I would check the following items first;
1. Sending unit terminal and gasket. Fuel can leak here and run down in an aft and inboard direction to deposit in the lower wing skin just forward of the aft spar. Then streak down the window in flight.
2. The rubber interconnect hoses between wing root and fuselage. These often get overlooked when it comes time to replace engine hoses, but they carry the fuel first on it's way to the engine.
3. The "B" nuts on the interconnect lines near those rubber hoses.

Barry

Here would be a far fetched thing....

You indicated that this same tank had been replaced before you purchased the plane. Was there any reason specified for this replacement? Had the tank been rubbing up against a protruding screw or rivet for some reason and it may have made a tiny hole in tank.

Also is the plane sitting level and fuel from left tank is not draining to right tank and maybe going out thru filler cap.

Noted was that you mentiond the cover is stained would indicate that fuel might be going out cap and cover is drawing it to the lower point. Try leaving your cover off and see if it does same. Also try filling left tank and leave right tank maybe a gallon or two lower than normal and see if it doesn't fill from left tank while sitting.

Bill

Barry

Since the cover is on top of the wing and fuselage it seems to me that the fuel is on top of wing which cover also may cover fuel caps. If it was just inside the wing, cover may not get stained from fuel. This is why it may be possible that fuel cap is leaking from overflowing.

Bill

Rich,
The fuel sending unit has sealed dome nuts, so no fuel will leak past the screws whether they have a wire terminal or washer under the head. The main access also has these sealed dome nuts. However you did cause me to remember another possibility for a leak. If someone installs a screw that is to long it can pierce the dome. Your comment about using the correct screws at all locations is important. More than once I've seen these aftermarket stainless screw kits come with the incorrect length.

Barry,
How goes the fuel leak?

Del