YS 91 ac - Check valves

[Henderson,Eric]

Anthony.
         Here's a dilemma for you. I had a problem with my OS 1.60 FI and immediately thought it was the injector. WRONG! There was no pressure in the tank. No pressure for the injector to use so injector-like problems... The weird thing was that the flapper in the check valve stuck in the closed position. It would work all day and then be closed the next day. I tried a few fixes with a file!!! but it still stuck the next day. Washed it, polished it even kissed it!, but still it did it again. Eventually put a motley-old-YS-check-valve in it and it runs like a watch. (BTW - the YS and OS check valves look identical)

Could not diagnose why the silicone would stick to the "outgoing" section. It would stick even when disassembled! My best guess was that the seat was too sharp...

Putting two check valves in gives you double the chance of a check valve staying closed.... :-)

Eric.

-----Original Message-----
From: discussion-request at nsrca.org
[mailto:discussion-request at nsrca.org]On Behalf Of Anthony Romano
Sent: Thursday, April 10, 2003 9:03 AM
To: discussion at nsrca.org
Subject: Re: YS 91 ac


Started putting two check valves in my planes just in case. The weight 
penalty is worth it.







>From: "jim ivey" <jivey61 at msn.com>
>Reply-To: discussion at nsrca.org
>To: discussion at nsrca.org
>Subject: Re: YS 91 ac
>Date: Wed, 09 Apr 2003 16:50:28 -0400
>
>William
>Eric hit the nail on the head. I had a problem,with a friends plane just 
>like this at The Peach Pattern Classic 2 weeks ago and it was the check 
>valve.I caught the problem when the tank didn't phutt(spew) much when 
>relieved of pressure.We changed the check valve and then had to reneedle 
>the engine.This solved the problem.
>I have had these pressure problems enough times, that I have made a 
>pressure tester.I used a hobby tire pump, a check valve (to keep the 
>pressure from leaking back through the pump) and a pressure gauge from 
>automotive supply.Plumb it with fuel tubing and you are in business. remove 
>the fuel supply tube from the engine and apply pressure here.This checks 
>the whole tank system,including the check valve. I usually pump to 10 psi 
>since the YS runs at 6-8 PSI. A tight system will hold pressure 'till next 
>week.
>
>Now all you-uns check my english too,'" etc.Not my best class in school 
>either.
>
>Jim Ivey
>
>Jim Ivey
>
>
>
>jivey61 at msn.com
>
>
>
>
>
>>From: "William Clemons" <W.Clemons at m.cc.utah.edu>
>>Reply-To: discussion at nsrca.org
>>To: <discussion at nsrca.org>
>>Subject: YS 91 ac
>>Date: Wed, 9 Apr 2003 12:42:00 -0600
>>
>>This is for the guys with YS 91 ac experience.  Have you ever had just a 
>>loss of pressure from the engine?  It will run fine for a minute and then 
>>dies.  I checked the fuel system for air leaks but cannot find any.  I 
>>even swapped needle valve assemblies thinking I might have a worn out one. 
>>  Any help is appreciated the engine has run fine up to this point.
>>Thanks in advance
>>William
>
>
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