Comanche Fuel Selector Stuck

SixPapaCharlie

SixPapaCharlie

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Not sure it matters but I have the model with 4 tanks.
The fuel selector over the last few months has been getting harder and harder to switch away from the right main tank.

I can switch to the other 3 with no issue but once I get on the right main, it takes everything I have to switch it to any other tank.
Today it was so bad that I decided I can't put it on the right tank again or it will be perm. froze there.

I have left a message with my mechanic but wondered if any other Manche pilots here have had this happen, know the cause and resolution.
 
Not a Comanche, but I’ve read about a stuck fuel selector valve on a Cirrus that was due to a loose screw. Hope you find the problem in yours without much trouble.
 
Different Piper, but take a look at: https://www.ntsb.gov/Advocacy/safety-alerts/Documents/SA-076.pdf

Specific text is "The fuel selector handle likely had been difficult to move for some time, and excessive force would have been required to move the handle from one position to another, thus causing the wear." And there's a picture.

No idea if PA-28 and PA-38 valves are similar, and not trying to over-inflate risk. I don't know. I'm only aware of it because I fly PA-28's and did a bunch of research.

Good luck and stay safe!
 
Albany Tom said:
Different Piper, but take a look at: https://www.ntsb.gov/Advocacy/safety-alerts/Documents/SA-076.pdf

Specific text is "The fuel selector handle likely had been difficult to move for some time, and excessive force would have been required to move the handle from one position to another, thus causing the wear." And there's a picture.

No idea if PA-28 and PA-38 valves are similar, and not trying to over-inflate risk. I don't know. I'm only aware of it because I fly PA-28's and did a bunch of research.

Good luck and stay safe!
Click to expand...
****
 
I have Comanche 250 but only two tanks. The selector is super hard to move, especially compared to the Cherokee I had before. The previous owner said it's normal, my mechanic has moved it and said nothing out of the ordinary so I don't worry about it. However, it never got to a point where it froze in place like yours did.
 
You have what's known as a Hoof type valve. Bone simple. Essentially, it's a rotating disk sandwiched between two housing plates, sealed with o-rings. When the hole in the disk lines up with one of the four holes in the housing, fuel passes. One of the o-rings is probably damaged or getting stuck or wasn't properly lubricated when assembled. or just sat in one place too long. Mine gets hard to turn in cold weather. Sometimes just working it a bit frees it up.

As long as the disk isn't badly corroded, it's a piece of cake to overhaul. You don't even need to drain the tanks if you're nimble with the fingers to screw in fuel plugs.

Be sure to tell your guy to use fuel lube to lubricate the o-ring seals. And not to lose the little steel ball at the end of the spring.

 
Chris: NOT normal. Your “250” is different than preceding post.

A bud had someone step on his Selector Valve . This broke the

Detent Washer and he was unable to switch tanks!

Once refueled; yours is easy to disassemble & lube.

Suggest you have a new o-ring and detent washer when you do

it. Newer Washers have a somewhat smaller slot that provides the detent

so the click is less obvious and the turning force is less.

The washers do wear so turning it over might be an option.

However; it is then prone to breaking.
 
s-l500.jpg
 
A lot of those old valves were simple tapered-plug type valves. They need to come out once every bunch of years to be relubricated with EZ-Turn lube (formerly Fuel Lube). If they're stiff and the pilot keeps forcing them, the shaft will break, maybe in a bad spot so that the engine doesn't get enough fuel.
 
Dan Thomas said:
A lot of those old valves were simple tapered-plug type valves. They need to come out once every bunch of years to be relubricated with EZ-Turn lube (formerly Fuel Lube). If they're stiff and the pilot keeps forcing them, the shaft will break, maybe in a bad spot so that the engine doesn't get enough fuel.
Click to expand...
Those are found on the two tank, 60 gallon 250 airframes or the airframes equipped with tip tanks and 4 valves. The 90 gallon airframes with 4 tanks have Hoof valves.
 
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