Citabria/Decathlon Fuel Valve

[Skymac]

Has anyone rebuilt one of these valve before? I can’t figure out what brand it is and they now use a different style valve. This one is a little weapy so I disassembled, but new orings in it, but haven’t tried yet.

It looked like it was supposed to have an O-ring at the bottom of the cone as well so I put one in because the old one appeared to have trash at the bottom that could’ve been a remnant of a worn out o-ring. Either way, it was worth $3 to try and save a valve.

 

[champ driver]

Here's a start,

http://www.burlac.com/fuel_valves.html

http://johnpropst.yolasite.com/resources/fuel shutoff valves overhaul rev7.pdf

 

[Dan Thomas]

There should be no O-ring under the valve rotor. Just around the shaft.

What did you lubricate it with? EZ-Turn (formerly Fuel Lube) is the right stuff. Anything else gets washed out right away. If the valve get stiff and hard to turn, the outer end of the shaft breaks off and the control shaft can't operate it anymore. Then you have to buy the new style and have a different mounting tab welded onto the vertical tube at the firewall.

 

[Mtns2Skies]

You can try to contact American Champion. Even if it's an older style, they're usually very open and helpful.

 

[Dan Thomas]

You can try to contact American Champion. Even if it's an older style, they're usually very open and helpful.

They're the folks I dealt with when our valve broke. They sold us the new-style valve because the old one wasn't built anymore, as well as the new mounting tab that I had to have welded on.

This was around 12 years ago. It's just another instance of commercial parts adapted to type-certified airplanes, parts that become obsolete because the vehicles or equipment they're normally used on have been redesigned or gone out of production. It's much cheaper for an OEM to incorporate such parts in a type-certified design, but now they're a tiny buyer of parts that can be obsoleted in an instant.

Cessna has the same problem with the fuel shutoff valve in the 150. Obsolete, no longer available. There are some outfits that rebuild them, but that can only last so long. Here in Canada a 150 can be re-registered in the Owner-Maintenance category, and a Weatherhead or Fairview fuel valve from a Kenworth truck or some other common piece of equipment could be adapted, as long as the valve's components are resistant to avgas. Some cheaper valves had plastic rotors in them that would dissolve and plug the fuel line.

 

[Skymac]

Here's a start,

http://www.burlac.com/fuel_valves.html

http://johnpropst.yolasite.com/resources/fuel shutoff valves overhaul rev7.pdf

Thanks for the document, printed and in the logs.

So when I went to the local rubber shop, we found an o-ring that fit perfectly in that bottom groove under the cone. I did use fuel lube, brushed up all the parts, reassembled, and it turns better now than it ever did, before it was extremely stiff. Also leak free for the least 24 hours. If something acts weird, I’ll know it’s from that bottom o-ring. Valve rarely gets moved anyhow.

 

[Dan Thomas]

Thanks for the document, printed and in the logs.

So when I went to the local rubber shop, we found an o-ring that fit perfectly in that bottom groove under the cone. I did use fuel lube, brushed up all the parts, reassembled, and it turns better now than it ever did, before it was extremely stiff. Also leak free for the least 24 hours. If something acts weird, I’ll know it’s from that bottom o-ring. Valve rarely gets moved anyhow.

The o-ring in the bottom might lift the valve rotor against the spring just enough to keep it from shutting completely off.

 

[Skymac]

I will report back at annual next month just for reference if anyone else stumbles upon this. Besides the weepy stem it never would shut off completely before, it was a small drip. Currently everything is 10-4 to my surprise, but we will let it get a little time on it. While looking down the barrel with everything tight, it lined up quite well.