[Stratus337]

I just bought my first skymaster, a 1973 P model. Bought it on the West coast and flew it back to the East coast the end of last week. I drained the sump drains to include rocking the wings after each of the 3 times I filled the tanks and had no evidence of water. I did have a steady drip fuel leak coming from the right sump drain after one of the times I drained it so when I got back I had my mechanic look at it and he recommended replacing the drain. Doing this required that he drain the fuel out of the wing. There was probably 20 gallons in the tank. To both of our surprise, probably 1/3 (yes, a third) of what came out of the tank was water!

The engine ran great, for the entire 3 leg/ 8 hour trip East. I am baffled as to (1) why water did not come out when I drained the tanks, and even more so (2) how the engine ran so well. The drain valve was corroded (probably because it was sitting in water) which is what caused the fuel leak. The plane has not been hangared the past 6 months or so, but water has not touched the airplane since I picked it up.

So while I'm curious why I did not see water and why the engine ran great, I really want to make sure I stop the water from getting in the tank in the future. I ran water through the overflow vent at the fuel fill cap this morning and it went straight through. That may not guarantee there is not a leak there, but it seemed to work well.

What about the access panels on top of the wing? Any chance that could be the source of water intrusion?

Any help would be greatly appreciated!

Thanks,
Paul