YS .91 idle setting

Tue Apr 8 08:03:17 AKDT 2003

Troy,

    Thanks for the info.  I'll print out your e-mail and try to get it set
up this afternoon.

Keith L. Hoard
Cordova, TN
klhoard at midsouth.rr.com
----- Original Message -----
From: "Troy Newman" <troy_newman at msn.com>
To: <discussion at nsrca.org>
Sent: Tuesday, April 08, 2003 10:43 AM
Subject: Re: YS .91 idle setting

> on YS motors all except the DZ the magic number on idle RPM's is
2000....not
> 2200 not 1900....2000 even....The reason for this is at 2000 rpm the
motors
> are no longer being force fed fuel...rather they are sucking it.....like a
> normal motor....To set the idle you need a tach...trim the rpms to 2000
even
> then watch the tach...if it surges slightly up then down and dies off its
> lean...if it sets at 2000 and the just dies off 19-18-17 dead...its
rich....
>
> On the FZ style motors (140 FZ, 63FZ and so on....) The 91AC and the 120SC
> the throttle barrel has a Idle adjustment air bleed screw...On the screw
on
> the throttle barrel in is rich and out is lean....In some case you can
take
> the screw almost out and its not lean enough. This is the case on early
> motors with this function.....There are 2 fixes...Take the throttle barrel
> out and remove the adjustment screw completely...then drill the hole in
the
> butterfly larger...Re-install the screw and you now have more adjustment
> available as the bigger the hole the more lean you can make it...This is a
> rare need...But I have had it happen....The regulator adjustment is made
at
> about 3000-4000 rpms.....Set like 3500 even...The watch the tach if it
> climbs then falls off the regulator is lean...dial it out...If the motor
> just slows down then its rich....
>
> Now at the idle setting if its too rich..before you re-drill the air bleed
> hole chances are the regulator is building too much pressure...meaning its
> rich anyway....So try to setup the midrange first.
>
>
> OK these are the adjustments.....order of operation is......High end
needle
> first...then idle...every change to the low end idle means you need to
clear
> the motor out and then reset tot he 2000 rpm and see what happens
> again....Then once the idle is set re-do the high speed needle....Then
> re-check the low end...Once they are good then go to the regulator and set
> the mid range....The go through the process again...Highend-low end-mid
> range.....they will all interact a little....
>
> another thing with the mid range...If the motor is running fine at first
but
> richens up after just a couple minutes of flying then the regulator is
> probably a little rich...Dial it out...What is happening is as pressure
> builds too much pressure gets built up and the motor is being force fed
> fuel....Leaner on the regulator means less pressure...hence less
> fuel....This is not a fuel pump...It pumps air! and meters the pressure in
> the tank.
>
> #2 goal is to not get the motors too hot on the ground...If you are
running
> more than about 2-3mins on the ground jacking with the setting its too
long
> and the motor is hot...Shut it down let it cool off then start
again...Once
> they are hot you will never get them set right....so they need to be
watched
> when running on the ground...If its good enough to fly..fly it and make a
> minor adjustment next flight. The worst thing you can do to a motor is
> ground run it..jacking with it...It gets hot...In the air the air flowing
> past cools thing down....On the ground the prop doesn't move enough air
over
> the and around the motor...
>
> As the motors break in from new the settings with stabilize....when they
are
> new...a richer setting is achieved because the motors parts are tighter
and
> make more heat...as the motor breaks in the setting will be too rich to
run
> and needs leaning...Usually this is high end and sometimes the low speed
> idle...but rarely the regulator screw....
>
> Starting points......High speed- 2 turns open, Low speed 1.5 turns
> open...Regulator screw flush with the case...maybe a little inside the
> case...You will always want the idle a little rich...So transition takes
> just a few moments....and instant screamin' eagle will make for a hot
> running motor as the instant throttle up will cause the motor to go
slightly
> lean then richen up...You can usually see this in the smoke trail the
motor
> has...As the motor will smoke slightly then go away and then smoke
> more....This is a little lean in the middle...Smoke at the very bottom-mid
> range and top end is great...Of course the volume will vary but the color
of
> the trail should be pretty constant....The High viscosity oils like the
Cool
> Power Heli Pro 20% or 30% work great in the DZ and also in the std
pressure
> systems of the YS....these fuels will smoke a little more.....and I have
> just started setting my motors based on my tach for idle and my ear and
the
> smoke trail...I can tell by flight times and by looking at the trail if
the
> motor is too rich or lean.....
>
> Ok hope this helps you out....
> good Luck
>
> Troy Newman
> ----- Original Message -----
> From: "Craig Miller" <cmiller51 at hotmail.com>
> To: <discussion at nsrca.org>
> Sent: Tuesday, April 08, 2003 5:48 AM
> Subject: Re: YS .91 idle setting
>
>
> > I have an AC that I've been flying with for the last two summers, and I
> > don't think I have the idle down to 2000 RPM, maybe at about 2400. It
> might
> > be that you have the idle too low (especially for a new engine). All you
> > need is an idle slow enough to land, and of course so the ship doesn't
> start
> > rolling before announcing your take off!
> >
> >
> >
> > Craig Miller
> > Remsen, Iowa
> > AMA 66900
> > NSRCA 2255
> > http://user.midlands.net/cmiller
> >
> >
> >
> >
> >
> > >From: "Keith Hoard" <khoard at midsouth.rr.com>
> > >Reply-To: discussion at nsrca.org
> > >To: <discussion at nsrca.org>
> > >Subject: Re: YS .91 idle setting
> > >Date: Mon, 7 Apr 2003 17:12:43 -0500
> > >
> > >Yup, got that. . . left is lean, right is rich. . . Just came in from
> > >messing with the low speed needle and it is set good for the
transition,
> > >but it still won't idle for more than 20-30 seconds.  I run it full
> > >throttle for about 10 seconds to pressurize the tank then drop it to
> idle -
> > >2000 to 2400 RPM.  The engine idles at this speed for about 20-30
seconds
> > >then the RPM slowly decays until it quits, then fuel drips out of the
> carb
> > >(engine inverted).  I relight the glow plug, spin the engine and it
> starts
> > >right up again and repeats.
> > >
> > >
> > >
> > >Keith L. Hoard
> > >Cordova, TN
> > >klhoard at midsouth.rr.com
> > >   ----- Original Message -----
> > >   From: Terry Brox
> > >   To: discussion at nsrca.org
> > >   Sent: Monday, April 07, 2003 5:03 PM
> > >   Subject: Re: YS .91 idle setting
> > >
> > >
> > >   Low speed is an airbleed. Out is leaner, in is richer. Opposite from
> the
> > >high speed.
> > >     ----- Original Message -----
> > >     From: Keith Hoard
> > >     To: NSRCA Mailing List
> > >     Sent: Monday, April 07, 2003 4:51 PM
> > >     Subject: Fw: YS .91 idle setting
> > >
> > >
> > >
> > >     From: Keith Hoard
> > >     To: NSRCA Mailing List
> > >     Sent: Monday, April 07, 2003 3:06 PM
> > >     Subject: YS .91 idle setting
> > >
> > >
> > >     Gentlemen,
> > >
> > >        I'm breaking in my YS .91FZ and seem to have gotten the top end
> > >working fine, but the engine idles at 2000 RPM for about 10 seconds
then
> > >slowly dies.  I don't remember which way to turn the low speed needle,
> and
> > >the YS Performance page seems to have been hijacked.  Thanks!!
> > >
> > >
> > >
> > >
> > >     Keith L. Hoard
> > >     Cordova, TN
> > >     klhoard at midsouth.rr.com
> >
> >
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