Need help with YS 63 & Dayton, OH Contest...

[David Harmon]

Hi Larry....good work!
That problem with the mold flash is pretty well known and while not a
problem on every unit, it does happen a lot. Another thing that will
cause the same problem is metal debris inside the hole in the regulator
housing that the plunger shaft goes through...the debris jams the
plunger shaft and holds open the valve causing pressurized fuel to pour
out of the carb and/or fill up the engine too.
 
Sorry I can't make it to Dayton this weekend as I'll be flying in
California.....but I'll be wearing a hardhat too!!
 
Have Fun!
 
Dave NSRCA 586

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of jed241 at msn.com
Sent: Thursday, May 29, 2003 10:12 PM
To: NSRCA
Subject: Re: Need help with YS 63 & Dayton, OH Contest...


Never got a reply on the e-mail below, but I think I found an
interesting problem. This may also apply to some of the other YS
problems with leaking fuel through the carb. I believe the part is
either the same or similar.
 
I pulled the regulator body apart and didn't find any debris. It was
very clean. After taking each piece apart and carefully inspecting for
any defects, I noted that the silicon seal that the plunger fits into,
and the spring fits on, may have caused the leak. Not due to damage or
wear, but poor quality control of the molding operation.
 
Around the outer edge, you can see thick flashing. When I set this in
the regulator body and looked very close when applying force to the
spring, there is an interference that would prevent proper sealing of
the seat. The interference is the flashing hitting the regulator body
and preventing the proper seal in the hole to the plunger.
 
I trimmed the flashing off and put it back together. Engine is better
than ever and no more leaking.
 
This makes sense as a brand new part could seal when new. After a few
flights and getting broke in, then the flashing prevents a good seal.
The only way to recover this would to increase the spring tension by
screwing in the adjustment screw to apply more force on the spring for
the seal.
 
Has anybody else seen this problem?
 
Engine is working fine now, so I guess I have to make my first contest
in Dayton, OH this weekend. After practicing in a cross wind, I think
I'm going to get my own hard hat just in case.<VBG> Should be at the
field around 5pm. I will need much help in trimming the plane. Didn't
get allot of flying time with the weather in southern Indiana. If anyone
is going to stay at a Holiday Inn let me know. I think I can get a
military discount for any rooms I pay for (you would have to give me the
money though ;^) Military rates are often the best rates Holiday Inn
offers.
 
See ya,
 
Larry


----- Original Message ----- 
From: jed241 at msn.com 
To: NSRCA <mailto:discussion at nsrca.org>  
Sent: Monday, May 26, 2003 5:12 PM
Subject: Need help with YS 63

The engine started leaking fuel through the carb just dripping out and
floods. It just started doing this. Tank pressure is good. I only have
about 10 flights on this engine and today is the first time it refused
to start.
 
I checked the diaphram in the regulator and it is in good shape.
 
Thanks for your help..
 
Larry


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