Quest and YS 1.10.

[Buff Miller]

Hey Eric,

Funny you should bring up this subject of integral gasket/diaphragms in the
YS regulators.  Lately, I've been "banking and yanking" with a little Aresti
with a YS 53 pulling it around. It too has the integral diaphragm. And, it
too is not flat.  The spring is smaller but quite a bit stronger than the
larger YS's.  Over time the spring has put a pretty good sized bulge in the
diaphragm.

The 53 hasn't spit any props, but it sure is insensitive on the needle valve
setting, while very sensitive on the brass regulator setting.

In fact, the other day the fuel was dripping quite heavily with the brass
regulator adjustment flush, as we're taught to set them.  This was while
there was pressure in the tank.  Releasing the pressure and the dripping
would stop.  To solve the problem, I cranked the brass screw in two turns.

While driving home, I was toying with the idea of putting a 120 - 140 type
round diaphragm in just to see if that would help.  Now I know I will do it.

Thanks for the very timely lead.

Buff

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Henderson,Eric
Sent: Sunday, November 23, 2003 7:37 PM
To: discussion at nsrca.org
Subject: Quest and YS 1.10.

With beautiful weather granted us in NJ this weekend we got to do a lot of
pre-winter flying. Joe Lachowski was defying all vertical gravity limits
with his Temptation. My newest Quest was given an airing and to my dismay
managed to spit the prop off in flight. This was the second time this engine
has done this. 

The first time it did the "prop-spit" I serviced the regulator and founds
some debris. The 1.10 (and the .91) uses a one piece gasket and combined
diaphragm. This time it was given closer inspection. It left me with the
impression that there could be an issue with the diaphragm. It was
definitely not flat and may have been the problem. 

So this time I decided to go a bit more radical and fitted a complete
replacement regulator from a YS 1.40. The regulator bolt and fuel hole
pattern is the same but the design is different. With the 1.40 version I
used a leak-free gasket and a "round" diaphragm.

The result was that the engine ran perfectly thereafter. It sounded a lot
better as it was opened-up and it idled very steadily.

I have heard of quite a few problems with 91's spitting props and could not
help wondering if there was perhaps a more 
generic problem with these one piece gasket/diaphragms. Either way I was
pleased that parts could be interchanged and that there is a fix.

 
Regards,

Eric.
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