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  #1  
Unread 02-27-20, 09:41 PM
wslade2 wslade2 is offline
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rebuild fuel selector valve

looks like I am going to need a fuel selector valve rebuilt. who does these for 337? (I haven't had chance to call McFarlane yet; I see they rebuild others.)
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  #2  
Unread 02-28-20, 05:54 PM
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Skymaster337B Skymaster337B is offline
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If it’s only leaking then it’s easy to replace the cork seal. But good luck getting that part. However, getting a sheet of cork and making the gasket is cheap and easy.
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  #3  
Unread 02-28-20, 11:51 PM
wslade2 wslade2 is offline
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It's not providing a positive cut off of fuel flow. Wish it was easy as just needing cork gasket. Internals will need to be serviced. Are there any flexible rubber/plastic life limited internal parts? Is there a service kit?
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  #4  
Unread 03-01-20, 04:02 PM
DrDave DrDave is offline
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I just went through this. The issue of leaking past the valve is from the little balls not sealing on the seats. The selector valve has a small well in it that can collect water. I think this contributes to the problem. The ball is held against the seat with a spring that is likely rusted. There will also be some rust on the seat that is causing your leak-past. You can remove the valve and see the ball/seat assembly. Don't remove the little clips that hold in the spring. They seem to be impossible to find. If a replacement clip/retainer was available this project would be pretty easy. I was only able to find one guy that was willing to look at them. He wanted a fortune and was a bit on the grumpy side.

I had one guy that thought removing the spring and ball and re-cutting the seat was the answer. I sent him one of my valves. It just sat on his desk for two months. On close inspection the seat was not pitted it appears to have surface rust that would likely clean up.

I think an ultrasonic cleaner would be a good start.

I found a pair of used valves that were not leaking.

Dave
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  #5  
Unread 03-01-20, 08:47 PM
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hharney hharney is offline
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Has anyone used B & S in Wichita lately?
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Herb R Harney
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  #6  
Unread 03-02-20, 09:19 AM
wslade2 wslade2 is offline
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I have been studying the valve drawings and come to the same conclusion myself about either corrosion (most likely) or some grit stuck in the ball/seat area. Also, been doing some research and B&S in Wichita is on my call list.
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  #7  
Unread 03-05-20, 08:34 PM
DrDave DrDave is offline
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I have one of the old valves on the shelf. I'll take some pictures so you can plan your attack.

Dave
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  #8  
Unread 03-05-20, 09:56 PM
wslade2 wslade2 is offline
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sounds great. surely there must be a matching internal c clip somewhere (I've been shopping internal c clip assortments-a kit with various assorted sizes very affordable) or if part is serviceable, clean things up and reuse.

Last edited by wslade2 : 03-05-20 at 09:58 PM.
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  #9  
Unread 03-06-20, 12:18 AM
DrDave DrDave is offline
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There is! It's this little self-destructing thing that springs itself out of position once removed.

Dave
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  #10  
Unread 03-07-20, 12:03 AM
DrDave DrDave is offline
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I dug out the old fuel selector valve. I have no recollection of how to attach a picture so I'm attaching several pictures. My computer has a .020" diameter thumbnail of the picture which is useless. Unfortunately I don't know how to add any descriptions to the pictures.
Attached Images
File Type: jpg IMG_0603.JPG (56.5 KB, 1048 views)
File Type: jpg IMG_0604.JPG (64.6 KB, 971 views)
File Type: jpg IMG_0605.JPG (48.2 KB, 953 views)
File Type: jpg IMG_0606.JPG (56.3 KB, 997 views)
File Type: jpg IMG_0607.JPG (111.8 KB, 1093 views)
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  #11  
Unread 03-07-20, 12:07 AM
DrDave DrDave is offline
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Here is a picture of the o-ring that sits on the shaft of the selector lever. This could be a source of leakage.
Attached Images
File Type: jpg IMG_0609.JPG (88.0 KB, 1016 views)
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  #12  
Unread 03-07-20, 02:33 AM
wslade2 wslade2 is offline
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oh my goodness. that internal clip that holds the spring does look like it will be a problem. I wonder if an internal c-clip would work in it's place.
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  #13  
Unread 03-07-20, 08:28 PM
DrDave DrDave is offline
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I will measure the thickness of it tomorrow. I don't have the right caliper to measure the inside groove diameter where it seats. One thing I would encourage is to take pictures and mark where the tubes go before you remove it.

Dave
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  #14  
Unread 04-10-20, 10:33 PM
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additional info?

I was wondering if there was any follow up to this posting. I got to fly my skymaster for the very first time today.....and what a machine these things are!!!! What I found out was that when we were flying on the main tanks, the front engine would also pull fuel from the aux tank. 2.5 hours of flying time used 8 gallons out of the left aux tank. I moved the selector valve around a bunch of times to see if there was something stuck in it that could get worked out, but used about the same out of the aux tank on the next 2.5 hour flight. I am thinking the balls and seats have corrosion on them as was shown in the pictures in the post. I didn't want to have my mechanic rip it apart until he was certain he could replace those clips if one were to be broken or lost in the process.

Also, in the post below there is mention of B and S in Wichita. Did you ever reach out to them regarding rebuilding the valve? Just trying to wrap my head around all the options.

Thanks much guys!!!
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  #15  
Unread 04-12-20, 11:17 AM
JAG JAG is offline
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Rigging

Tom,
I am not saying that it could not be some internal corrosion or problem in the valve, but if you have not verified, just double check the rigging of the valve. One small panel on at the wing root and a mirror, and you can verify that the valve is in the detents and rigged properly.
Jeff
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