[NSRCA-dist4] YS-120NC vs. me

[Bob Kane]

>From what you describe the regulator is no longer regulating. The regulator has 8 parts, the gasket, regulator body, regulator screw, o-ring seal for the regulator screw, the spring, the regulator plunger (looks like a small poppet valve, made of brass) and two other key parts, the diaphragm and the plunger "tip", both made of silicone. The spring is probably OK, but I'll bet the diaphragm and the regulator "tip" need replacing. I think you have to buy plunger and tip together, the diaphragm you can buy by itself. They are not difficult to rebuild, just pay attention to which side of the gasket the diaphragm goes on.

 Bob Kane
getterflash at yahoo.com




________________________________
From: bruce & sandy <bruceher at bright.net>
To: nsrca d4 list <nsrca-dist4 at lists.nsrca.org>
Sent: Monday, May 25, 2009 7:08:00 AM
Subject: [NSRCA-dist4] YS-120NC vs. me

 
Hi Guys,
 
Need a little help/advice here.  Trying to get 
this YS-120NC running that I bought several years ago.  I think it was 
supposed to be new, but you know how that goes.  I think it's a regulator 
problem, but I have almost no experience with regulators.  I'm sure you 
realize how rare someone with YS engine experience is in and around Quincy, 
Ohio!!
 
First attempts--High speed needle about 2 turns 
out.  Regulator adjusting screw even with top of regulator housing.  
Finally got a real rough idle (think I turned regulator adjusting screw in 
slightly).  Advancing throttle killed it right away, indicating a real rich 
idle.  I was tired and put plane in barn.  While I was away all of the 
unused fuel syphoned out of the tank on to the floor (no biggie, 
remember it is a barn!).  Hard to tell where it leaked out (inverted 
engine)  imagine it came out the carb intake, but it certainly came through 
the regulator.
 
In desperatiion, yesterday I screwed the regulator 
adjusting screw all the way in until it seated.  Don't think I backed it 
off at all.  Engine started with a kind of rough idle.  Transition to 
full throttle (needle 2 turns out) was good.  I didn't play anymore.  
Imagine if I back off the adjusting screw to get a smooth idle, the unused fuel 
will again syphon out of the tank.
 
So,  you YS wizards, what do I do?  If I 
should replace the diaphram in the regulator, do I replace the spring 
too?  Guess replacing the gasket is a given.
 
Sorry about this, but I don't have anybody to talk 
to.
 
Thanks,
 
Bruce


      
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