Fuel selector valve...

Fuel selector valve malfunction  

Active Member

I was flying a couple days ago and went to switch tanks when the handle and rod for the fuel selector pulled right out. It had been pretty tough to turn so I had been applying back pressure and turning at the same time as I had seen suggested, and that did lessen the resistance. I was planning on rebuilding the valve and the day before had been reading through posts to educate myself on the procedure, so of course this had to happen the next day! I have a 108-1 with the f150 and I think the 3/8” valve. It looks as though the square end of the valve stem where the rod fits over blew out (see pic). Any suggestions on repairing that, is it even possible? If not, does anyone happen to have a spare valve stem they’re willing to sell?  Thanks for the help!

BF15C264 D147 41A9 B463 F1BA436FB6EB


Posted : 04/12/2019 2:30 pm
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Sorry to hear about this, the valve is brass, and the end is square, the rod is held by a cotterpin, so wear causes the square to deteriorate.

there was a long discussion on this at the YAhoo group, I will attempt to pull that into our knowledge base and link to it this week.

Posted : 04/12/2019 3:37 pm
sqyare end
IMG 6319
Posted : 04/12/2019 8:54 pm

I don't have a spare valve for you, sorry. With luck you can fix your existing valve but in case you need the info................ Univair sells an approved replacement valve, not the original brass valve but it is an exact fit replacement and mounts directly, no modifications required. It is actually a better valve than the original, has nice detent action and nice smooth motion. It is not cheap but by certified aircraft new parts standards is not bad. The Univair kit includes adapters to make the replacement valve fit the compression fitting connections on the stock fuel lines.

Since your plane is a 150 there are no limitations on the installation. If one has a larger engine retrofitted to the airplane there are horsepower limits to the replacement valves - Univair got them certified to the needs of the existing stock engines but did not get them approved for flow needs for higher horsepower engines. Most likely they would work just fine with a bigger engine but they are not officially approved for it.

One final thought would be to try Earl Allen out in California. He parts out Stinson 108's and might have a serviceable original or Univair valve in stock from some plane he parted out. He might have the long rod that connects the valve to the valve handle if yours is worn badly, also.

Bob and Pat and the two Stinsons

Posted : 08/12/2019 4:02 pm