Curtis drain valves

For the last month or so, when I check for water in the tanks during preflight the drain valves drain very slow. Tonight I took them out to see whats up. I found, I'm not sure what inside them. It looked like maybe part of a worm, or maybe algae. I cleaned them out and put them back, but if I screw them in where I think they should be, so as not leak or loosen up I can't push on them to get fuel out. If I back them out a turn they work fine. They are brass so maybe they crush a little if they are to tight, I just don't know. Also I looked in the tanks with a flashlite and they are clean(spotless) Anybody have any thoughts. Thanks

Tim
2+2

There have been reports of Curtis valves falling apart, resulting in a complete loss of fuel. Sounds like something is wrong with yours. Valves are cheap, having it fall apart might not be, replace it.

delete

Curtis valves use a special washer. I replaced mine with valves from Safe-Air. They use standard o'rings. You can't buy the special Curtis seal anymore.

Steve Pierce

delete

Try Trimcraft in Genoa City, WI for Curtis replacement seals 800-558-9405, they may still sell them. I like to use the F391 (Cessna style) flush drain on the right tank. It cannot be bumped open by the window like a Saf-air. It's seal is not replaceable, but it is not that expensive to replace the whole unit when it starts to leak.

Safe-Air sells a flush model too. I had the same problem. I'll look up the part number. Thanks for the number, I'll call today and see if the seals are available.

Installing a new Saf-Air flush valve. Looks like the old F391, but built more rugged, and can be disassembled, cleaned, and standard o-ring replaced. P/N is SA14 for the 1/4 inch pipe tread in S-Cub tanks, will see how it holds up over time.

Well, that test didn't take long. The Saf-Air flush valve is a piece of crap. After about half a dozen (I lost count, must be the gas fumes), attempts to get it to seal, I have given up. The problem appears to be overcut, to few, and just plain old bad machining on the 1/4 inch pipe threads. Having goobed the threads with various sealants, overtorqueing the thing in to the point I was very afraid I would crack the tank boss, streaching the tank boss open so far that the base of the valve bottomed against the tank, the F#^!*'ing piece of sh#*t STILL LEAKED! I cleaned the original valve, which reinstalled just finger tight with no sealant doesn't leak. I will spend more in shipping on this damn thing to send it back than it costs, but I'm sending it back, just out of principle. I wouldn't use this thing on my tractor, much less a aircraft. I was going to buy a bunch of these to use on customers aircraft, glad I only waisted money on one of them "to test" first. Now maybe I just got a bad one, sh#*t happens, they have a web site on the package the valve came in, I tried to contact them about it, but their web site appears to work just as well as their valves. Back to the old F391, the seal is not replaceable, but at least it fits the tank.