Gaskets

[William C. Harden]

Georgie,

If the engine won't come down to idle and the carburetor is closed, then
you have an air leak.  

The air leak could be caused by any of the gaskets including the air box
and valve cover, as well as any of the O' rings. The valve cover gasket
is notorious for this problem.  Also consider the O' rings on the pipe
at the air box and the engine head; also the O' rings at each end of the
pushrod external tubes (at the head and engine case).

Good luck.

Bill Harden



-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of george kennie
Sent: Thursday, September 18, 2003 7:50 PM
To: discussion at nsrca.org
Subject: Re: Gaskets

Guys,
Thanks for trying.
The engine is a 91 AC and has been sitting idle for about 2 years. 2
years ago
it was running O.K., but when I tried to run it in a  new airplane it
did not
run very well. It starts O.K. and the top end seems good, but when I try
to come
back to idle it only comes down to about 6k rpm and this is with the
barrel
CLOSED and after running for about at least 30 seconds it may slow to
2200 with
sporadic intervals where it almosts quits and then sometimes will speed
back up
to 6k again and once again, all with the barrel closed.
The regulator gasket is the diaphragm and I replaced that. I blew out
all
passages in the regulator body and they are free and clear. I checked
the
silicone plunger and it checks O.K.  The plunger shaft was checked for
freedom
of movement, again O.K. The shut-off action of the plunger was checked
and
operated as designed. The regulator screw is adjusted flush. The
air-bleed screw
is adjusted 1&1/2 turns out(I've tried it from closed to 5 turns out).
The needle valve body has been blown clear and a small wire run thru the
passages to insure that no foreign material is clogging anything.New
O-rings
installed on the needle valve body.New O-ring at the base of the airbox.
The
backplate, carburetor body, and airbox gaskets replaced and all screws
adequately retightened. The valves adjusted and the cover base dressed
flat and
reassembled with a new gasket. After all this the engine runs like it
has an air
leak somewhere.
When I adjust the throttle from the 6k rpm point to return to full
throttle it
sounds like it's starving for 2 or 3 seconds before it starts to recover
to full
speed.
Tank pressure is strong and fuel flow to the carb is good.
I'm at my wits end and I'm not that keen on sending it to the repair
facility as
I sent my 63 to them a couple of months ago and it came back the same
way it
went in.Now I'm stuck with two engines that are unusable.
Any further ideas will be gratefully received.
Georgie


Tony Stillman wrote:

> George:
> The only real problem was the regulator gasket.  High nitro, over
time, will
> cause the tiny fuel passage hole to close up.  The new regulator
gasket
> material is black, and does not have this problem.  The "Leak Free"
brand
> was also a different material, and will not clog.
>
> If you have to old brown "paper" regulator gasket, just replace it
with the
> regulator gasket that is available seperately for about $1.50.
>
> Tony Stillman
> Radio South
> 3702 N. Pace Blvd.
> Pensacola, FL 32505
> 1-800-962-7802
> www.radiosouthrc.com
> ----- Original Message -----
> From: "george kennie" <geobet at gis.net>
> To: <discussion at nsrca.org>
> Sent: Thursday, September 18, 2003 12:39 PM
> Subject: Gaskets
>
> > Hey Guys,
> > Need a little help here!
> > Some of you YS gurus please respond.
> > I remember seeing Leak Free Gaskets advertised some time back. What
I
> > would like to know is, why was there a market for this product? Does
the
> > motor start to malfunction in some way that indicates to you that
you
> > need new gaskets or that there may be a gasket leak somewhere and
what
> > are the symptoms. Does the motor cease to run or does it become
errattic
> > in some way? Please be specific as I feel that I may be experiencing
> > gasket woes.
> > Thanks for any help you can send my way.
> > Georgie
> >
> > =====================================
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> > #
> >
> >
> >
>
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